CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 113102503, filed on Jan. 23, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
BACKGROUND
Technical Field
This disclosure relates to an electroplating technology, and in particular to an electroplating apparatus.
Description of Related Art
A conductive through hole is a part of the circuit structure in a circuit board or wafer, and is used to electrically connect two or more circuit layers. In detail, the manufacturing process of the conductive through hole uses etching, laser or mechanical drilling to form through holes in the insulating substrate or semiconductor substrate, and then performs electroplating hole filling to fill the through holes with copper to form conductive through holes. If the electroplating quality is poor, the probability of uneven or incomplete hole filling are relatively high, such as the formation of voids in the conductive through hole, which affects the resistance and current loading capability of the conductive through holes.
SUMMARY
An electroplating apparatus according to an embodiment of the disclosure is adapted to electroplate an object to be plated having multiple through holes. The electroplating apparatus includes a plating tank, a first anode plate disposed in parallel with a second anode plate in the plating tank, a cathode plate connected to the object to be plated, a first sensing module, and a second sensing module. The cathode plate and the object to be plated are disposed in the plating tank and located between the first anode plate and the second anode plate. The first sensing module and the second sensing module are disposed in the plating tank and are located between the first anode plate and the second anode plate. The first sensing module includes a light source disposed between the object to be plated and the first anode plate, and a light sensor disposed between the object to be plated and the second anode plate. The second sensing module includes a first electrical sensor disposed between the object to be plated and the first anode plate, and a second electrical sensor disposed between the object to be plated and the second anode plate.
To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a schematic cross-sectional view of an electroplating apparatus according to an embodiment of the disclosure.
FIG. 2A is a partially enlarged schematic view of a region R1 in FIG. 1.
FIG. 2B is a partially enlarged schematic view of a region R2 in FIG. 1.
FIG. 3A is a partially enlarged schematic view of a region R3 in FIG. 1.
FIG. 3B is a partially enlarged schematic view of a region R4 in FIG. 1.
FIG. 4A to FIG. 4H are schematic front views of a first nozzle and a nozzle plate thereof in FIG. 3A in different examples.
FIG. 5 is a top view of an object to be plated.
FIG. 6A to FIG. 6D are partial cross-sectional schematic views of a process of electroplating hole filling in multiple regions of the object to be plated in FIG. 5.
DESCRIPTION OF THE EMBODIMENTS
FIG. 1 is a schematic cross-sectional view of an electroplating apparatus according to an embodiment of the disclosure. FIG. 2A is a partially enlarged schematic view of a region R1 in FIG. 1. FIG. 2B is a partially enlarged schematic view of a region R2 in FIG. 1. Referring to FIG. 1, FIG. 2A, and FIG. 2B, in this embodiment, an electroplating apparatus 100 is adapted to be used in circuit board processes or semiconductor processes, and is adapted to electroplate an object to be plated 10. Furthermore, the object to be plated 10 may be an insulating substrate or a semiconductor substrate having multiple through holes 11, and each of the through holes 11 may be a hole with a high aspect ratio that penetrates the insulating substrate or the semiconductor substrate.
As shown in FIG. 1, the electroplating apparatus 100 includes a plating tank 110, a first anode plate 120a, a second anode plate 120b, a cathode plate 130, a first sensing module 140, and a second sensing module 150. Specifically, the first anode plate 120a is disposed in parallel with the second anode plate 120b in the plating tank 110, and at least a portion of the first anode plate 120a and at least a portion of the second anode plate 120b are immersed in an electroplating solution. In addition, the cathode plate 130 and the object to be plated 10 are disposed in the plating tank 110, and in the X direction, the cathode plate 130 and the object to be plated 10 are located between the first anode plate 120a and the second anode plate 120b. At least a portion of the cathode plate 130 is immersed in the electroplating solution. The object to be plated 10 is completely immersed in the electroplating solution and connected to an end of the cathode plate 130.
During an electroplating process, the object to be plated 10 connected to the cathode plate 130 serves as a cathode, and metal ions in the electroplating solution may be reduced to metal on the cathode to be deposited in the each of the through holes 11 of the object to be plated 10 (refer to FIG. 2A and FIG. 2B). Additionally, the first anode plate 120a and the second anode plate 120b may be soluble anodes, insoluble anodes, or a combination thereof. For example, the soluble anodes may oxidize and generate metal ions during the electroplating process to complement the reduced metal ion concentration in the electroplating solution due to the cathodic reduction reaction. On the other hand, the insoluble anodes may generate hydroxide ions for oxidation during the electroplating process to stabilize the metal ion concentration in the electroplating solution.
As shown in FIG. 1 and FIG. 2A, in this embodiment, the first sensing module 140 is disposed in the plating tank 110 and is completely immersed in the electroplating solution. In detail, the first sensing module 140 includes a light source 141 and a light sensor 142. In the X direction, the light source 141 is disposed between the object to be plated 10 and the first anode plate 120a, and the light sensor 142 is arranged between the object to be plated 10 and the second anode plate 120b. The light source 141 may be a light emitting diode or a gas discharge tube, and is adapted to project light with a wavelength ranging from 400 nanometers to 700 nanometers to the object to be plated 10. In other examples, the light source may be an infrared light source, an ultraviolet light source, a laser light source, a halogen light source, or other light sources adapted to be used for image inspection.
During an electroplating hole filling process of the each of the through holes 11, a bridge is first formed in the each of the through holes 11, and then two openings opposite to each other are deposited from the bridge to fill the through hole 11 completely. In order to monitor the filling condition in real time, the light source 141 may project light to the each of the through holes 11, and detect the light passing through the each of the through holes 11 through the light sensor 142 to determine the formation state of the bridge in the each of the through holes 11, so as to ensure that each of the through holes 11 may be completely filled to form a conductive through hole without voids.
As shown in FIG. 1 and FIG. 2B, in this embodiment, the second sensing module 150 is disposed in the plating tank 110 and is completely immersed in the electroplating solution. In detail, the second sensing module 150 includes a first electrical sensor 151 and a second electrical sensor 152. In the X direction, the first electrical sensor 151 is disposed between the object to be plated 10 and the first anode plate 120a, and the second electrical sensor 152 is disposed between the object to be plated 10 and the second anode plate 120b. The first electrical sensor 151 and the second electrical sensor 152 may be reference electrodes and include silver/silver chloride electrodes, calomel electrodes, or saturated mercury/mercurous sulfate electrodes.
During the electroplating hole filling process of the each of the through holes 11, in order to monitor the filling condition in real time, the first electrical sensor 151 and the second electrical sensor 152 may measure changes in potential or current to determine at least one of a bridge formation rate, a bridge formation state, a hole filling rate, and a hole filling state in the each of the through holes 11, so as to ensure that each of the through holes 11 may be completely filled to form a conductive through hole without voids.
As shown in FIG. 1, in this embodiment, the first anode plate 120a and the cathode plate 130 are separated by a first distance D1 in the X direction, and the second anode plate 120b and the cathode plate 130 are separated by a second distance D2 in the X direction. The first distance D1 and the second distance D2 are equal and remain unchanged, for example, between 3 cm and 10 cm.
In detail, the electroplating apparatus 100 further includes a first positioning bracket 160a disposed in parallel with a second positioning bracket 160b in the plating tank 110, and at least a portion of the first positioning bracket 160a and at least a portion of the second positioning bracket 160b are immersed in the electroplating solution. On the other hand, the cathode plate 130 is clamped and positioned between the first positioning bracket 160a and the second positioning bracket 160b. In the X direction, the first positioning bracket 160a is located between the first anode plate 120a and the cathode plate 130, and the second positioning bracket 160b is located between the second anode plate 120b and the cathode plate 130.
As shown in FIG. 1, FIG. 2A, and FIG. 2B, in the X direction, the first sensing module 140 is disposed between the first positioning bracket 160a and the second positioning bracket 160b, the light source 141 is connected to a side of the first positioning bracket 160a facing the cathode plate 130 or the object to be plated 10, and the light sensor 142 is connected to a side of the second positioning bracket 160b facing the cathode plate 130 or the object to be plated 10. On the other hand, in the X direction, the second sensing module 150 is disposed between the first positioning bracket 160a and the second positioning bracket 160b, the first electrical sensor 151 is connected to the side of the first positioning bracket 160a facing the cathode plate 130 or the object to be plated 10, and the second electrical sensor 152 is connected to the side of the second positioning bracket 160b facing the cathode plate 130 or the object to be plated 10.
As shown in FIG. 1, in this embodiment, the electroplating apparatus 100 further includes an eccentric swing module 170. The eccentric swing module 170 is disposed above the plating tank 110 and connected to the cathode plate 130. In detail, the eccentric swing module 170 includes a motor 171, a driving rod 172, and a connecting rod 173. The driving rod 172 is connected to the motor 171 and is adapted to be driven by the motor 171 to rotate around an axis AX. For example, the driving rod 172 extends in the X direction and is parallel to the axis AX. In the Y direction, the driving rod 172 is separated from the axis AX by an eccentric distance D3.
On the other hand, the connecting rod 173 extends in the Y direction and is perpendicular to the driving rod 172. Furthermore, the driving rod 172 is connected to the cathode plate 130 through the connecting rod 173. When the driving rod 172 is driven by the motor 171 to rotate around the axis AX, the connecting rod 173, the cathode plate 130, the object to be plated 10, the first bracket 160a, and the second bracket 160b are adapted to rotate around the axis AX synchronously with the driving rod 172. In addition, a rotation speed of the motor 171 may range from 5 rpm to 400 rpm.
Since the object to be plated 10 can be swung along a specific path in the electroplating solution by the eccentric swing module 170, and has a moving stroke in the Y direction and Z direction, the uneven or incomplete filling of the each of the through holes 11 may be improved, so as to ensure that each of the through holes 11 may be completely filled to form a conductive through hole without voids.
For example, the eccentric distance D3 may be 1/10 to ½ times a distance D4 from an edge of the object to be plated 10 to a center of the object to be plated 10. For example, if the object to be plated 10 is a circular object, the center of the object to be plated 10 may be the center of the circle, and the distance D4 may be the radius of the object to be plated 10. For example, if the object to be plated 10 is a geometrically shaped object to be plated, the center of the object to be plated 10 may be the geometric center. For example, if the object to be plated 10 is a parallelogram, the center of the object to be plated 10 may be the geometric center, i.e., the intersection of the two diagonals of the parallelogram.
FIG. 3A is a partially enlarged schematic view of a region R3 in FIG. 1. FIG. 3B is a partially enlarged schematic view of a region R4 in FIG. 1. Referring to FIG. 1, FIG. 3A, and FIG. 3B, in this embodiment, the electroplating apparatus 100 further includes multiple first nozzles 180a and multiple second nozzles 180b. Each of the first nozzles 180a and each of the second nozzles 180b are disposed in the plating tank 110 corresponding to the object to be plated 10, and are completely immersed in the electroplating solution. Furthermore, the each of the first nozzles 180a is connected to a side of the first anode plate 120a facing the cathode plate 130 or the object to be plated 10, and the each of the second nozzles 180b is connected to a side of the second anode plate 120b facing the cathode plate 130 or the object to be plated 10.
For example, the each of the first nozzles 180a is integrated with the first anode plate 120a and penetrates the first anode plate 120a to protrude from the side of the first anode plate 120a facing the cathode plate 130 or the object to be plated 10. In addition, the each of the second nozzles 180b is integrated with the second anode plate 120b and penetrates the second anode plate 120b to protrude from the side of the second anode plate 120b facing the cathode plate 130 or the object to be plated 10. In the X direction, the cathode plate 130, the object to be plated 10, the first sensing module 140, and the second sensing module 150 are located between the each of the first nozzles 180a and the each of the second nozzles 180b.
In other examples, the each of the first nozzles 180a is integrated with the first anode plate 120a, and is embedded in the first anode plate 120a to be flush with the side of the first anode plate 120a facing the cathode plate 130 or the object to be plated 10. In addition, the each of the second nozzles 180b is integrated with the second anode plate 120b, and is embedded in the second anode plate 120b to be flush with the side of the second anode plate 120b facing the cathode plate 130 or the object to be plated 10.
As shown in FIG. 1, FIG. 3A, and FIG. 3B, in this embodiment, the each of the first nozzles 180a has a jet opening 181a facing the object to be plated 10, and the each of the second nozzles 180b has a jet opening 181b facing the object to be plated 10. As a result, the each of the first nozzles 180a and the each of the second nozzles 180b may spray the electroplating solution on the object to be plated 10 in the X direction to improve hole filling efficiency and hole filling quality of the each of the through holes 11.
As shown in FIG. 1, in the Y direction, the each of the first nozzles 180a has a different depth from a liquid level 111 of the plating tank 110 to be arranged in multiple rows on the first anode plate 120a. Furthermore, the first nozzles 180a in the same row are arranged in the Z direction. On the other hand, in the Y direction, the each of the second nozzles 180b has a different depth from the liquid level 111 of the plating tank 110 to be arranged in multiple rows on the second anode plate 120b. Furthermore, the second nozzles 180b in the same row are arranged in the Z direction.
In this embodiment, the electroplating apparatus 100 further includes multiple first flow meters 190a disposed corresponding to the first nozzles 180a in different rows, and multiple second flow meters 190b disposed corresponding to the second nozzles 180b in different rows. In detail, the first nozzles 180a in the same row are connected to the same first flow meter 190a to control or regulate the first nozzles 180a at the same depth of the liquid level to spray the same flow of electroplating solution by the same first flow meter 190a. In addition, the second nozzles 180b in the same row are connected to the same second flow meter 190b to control or regulate the second nozzles 180b at the same depth of the liquid level to spray the same flow of electroplating solution by the same second flow meter 190b.
For example, the first flow meter 190a may control or regulate a spray flow rate of the first nozzle 180a between 0.2 liters per minute and 15 liters per minute, and the second flow meter 190b may control or regulate a spray flow rate of the second nozzle 180b between 0.2 liters per minute and 15 liters per minute. As the depth of the liquid level gets deeper, the first flow meter 190a may increase the spray flow rate of the first nozzle 180a, and the second flow meter 190b may increase the spray flow rate of the second nozzle 180b to increase the flow rate of the electroplating solution near the bottom of the plating tank 110 or the efficiency of exchange.
As shown in FIG. 1, in this embodiment, the electroplating apparatus 100 further includes at least one row of bottom nozzles disposed at the bottom of the plating tank 110. First bottom nozzles 180c and second bottom nozzles 180d, which are arranged in two rows in the Z direction, are illustrated here, but are not limited thereto. In the X direction, the first bottom nozzle 180c is located between the cathode plate 130 and the first anode plate 120a, and the second bottom nozzle 180d is located between the cathode plate 130 and the second anode plate 120b.
For example, a distance D5 between the first bottom nozzle 180c and the cathode plate 130 is less than or equal to ⅓ times the first distance D1, and a distance D6 between the second bottom nozzle 180d and the cathode plate 130 is less than or equal to ⅓ times the second distance D2.
In this embodiment, the electroplating apparatus 100 further includes at least one bottom flow meter. First bottom flow meters 190c and second bottom flow meters 190d, which correspond to the first bottom nozzles 180c and the second bottom nozzles 180d, are illustrated here, but are not limited thereto. In detail, the first bottom flow meter 190c is connected to the first bottom nozzle 180c in the same row to control or regulate the first bottom nozzle 180c in the same row to spray the same flow rate of electroplating solution. In addition, the second bottom flow meter 190d is connected to the second bottom nozzle 180d of the same row to control or regulate the second bottom nozzle 180d of the same row to spray the same flow rate of electroplating solution.
Referring to FIG. 1, in this embodiment, an inert gas injection port 112 is disposed at the bottom of the plating tank 110. In the X direction, the inert gas injection port 112 is located between the first anode plate 120a and the second anode plate 120b, and is located between the bottom nozzle 180c and the second bottom nozzle 180d. In detail, the inert gas injection port 112 extends in the Z direction. In the Y direction, the object to be plated 10 is located between the cathode plate 130 and the inert gas injection port 112, and at least a portion of the inert gas injection port 112 falls within a projection range of the cathode plate 130 on the bottom of the plating tank 110.
For example, the inert gas injection port 112 may inject nitrogen or other inert gas into the electroplating solution to reduce the oxygen concentration and prevent oxidation.
FIG. 4A to FIG. 4H are schematic front views of a first nozzle and a nozzle plate thereof in FIG. 3A in different examples. Referring to FIG. 1, FIG. 3A, and FIG. 3B, in this embodiment, the structural designs of the first nozzle 180a, the second nozzle 180b, the first bottom nozzle 180c, and the second bottom nozzle 180d are the same or similar, as explained below through the structural design of the first nozzle 180a, and the structural designs of the second nozzle 180b, the first bottom nozzle 180c, and the second bottom nozzle 180d will not be repeated in the following.
As shown in FIG. 1 and FIG. 4A, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 101, and the nozzle sheet 101 has jet holes distributed in a tile shape. As shown in FIG. 1 and FIG. 4B, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 102, and the nozzle sheet 102 has jet holes distributed in a rhombus shape. As shown in FIG. 1 and FIG. 4C, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 103, and the nozzle sheet 103 has jet holes distributed in a tile shape or fish-scale shape. As shown in FIG. 1 and FIG. 4D, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 104, and the nozzle sheet 104 has jet holes distributed in a knitted shape.
As shown in FIG. 1 and FIG. 4E, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 105, and the nozzle sheet 105 has jet holes distributed in a honeycomb shape. As shown in FIG. 1 and FIG. 4F, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 106, and the nozzle sheet 106 has multiple jet holes 1061. In detail, the jet holes 1061 are multiple circular holes and are arranged in multiple circles from a center of the jet opening 181a outward, and in the radial direction of the jet opening 181a, a hole diameter of the jet hole 1061 decreases from inward to outward. As shown in FIG. 1 and FIG. 4G, in one example, the jet opening 181a of the first nozzle 180a is equipped with a nozzle sheet 107, and the nozzle sheet 107 has jet holes distributed in a stripe shape. As shown in FIG. 1 and FIG. 4H, in one example, the jet opening 181a of the first nozzle 180a is not equipped with a nozzle sheet, and the jet opening 181a is a single circular opening.
For example, the hole diameter of the jet holes in the above examples ranges from 1.9 mm to 5.2 mm.
FIG. 5 is a top view of an object to be plated. FIG. 6A to FIG. 6D are partial cross-sectional schematic views of a process of electroplating hole filling in multiple regions of the object to be plated in FIG. 5. Referring to FIG. 1 and FIG. 5, the object to be plated 10 may be swung along a specific path in the electroplating solution by the eccentric swing module 170, and has a moving stroke in the Y direction and Z direction. Therefore, by this swing design, an electroplating rate and electroplating uniformity in each region RC, RT, RB, RR, and RL of the object to be plated 10 may be made uniform to minimize the difference between a thickness of a surface electroplating layer in the region RC and thicknesses of surface electroplating layers in the other regions RT, RB, RR, and RL. For example, the region RC is a central region of the object to be plated 10, and the regions RT, RB, RR, and RL are peripheral regions outside the central region.
Referring to FIG. 5, FIG. 6A, and FIG. 6B, a wet metallization technique is first used to form an adhesion layer 20 on a surface of the object to be plated 10 and on an inner wall surface of the each of the through holes 11 in the each region RC, RT, RB, RR and RL. Next, referring to FIG. 5 and FIG. 6C, the object to be plated 10 is plated, e.g., the each of the through holes 11 in the each region RC, RT, RB, RR, and RL is plated and filled. During the process of electroplating hole filling in the each of the through holes 11, a bridge 501 is first formed in the each of the through holes 11, and then two openings opposite to each other are deposited from the bridge 501 to fill the through hole 11 completely, so as to form a conductive through hole 50 as shown in FIG. 6D.
As shown in FIG. 2A and FIG. 6C, in order to monitor the formation state of the bridge 501 in real time, the light source 141 may project light to the each of the through holes 11, and detect the light passing through the each of the through holes 11 through the light sensor 142 to determine whether the bridge 501 in the each of the through holes 11 is completely formed. For example, when the bridge 501 in the each of the through holes 11 is completely formed, the light emitted by the light source 141 is blocked by the bridge 501 in the each of the through holes 11, and therefore cannot be detected by the light sensor 142 to determine that the bridges 501 are completely formed.
As shown in FIG. 2B, FIG. 6C, and FIG. 6D, during the process of electroplating hole filling in the each of the through holes 11, the first electrical sensor 151 and the second electrical sensor 152 may measure changes in potential or current to determine at least one of a bridge formation rate, a bridge formation state, a hole filling rate, and a hole filling state in the each of the through holes 11, so as to ensure that each of the through holes 11 may be completely filled to form a conductive through hole without voids.
As shown in FIG. 1 and FIG. 6D, since the object to be plated 10 is swung along a specific path in the electroplating solution by the eccentric swing module 170, a thickness of a surface electroplating layer 40 on the object to be plated 10 may be uniform in the each region RC, RT, RB, RR, and RL, e.g., the maximum difference in thickness may be less than or equal to 6 micrometers, and the electroplating uniformity may be greater than 95%.
In summary, the electroplating apparatus of the disclosure may monitor the electroplating hole filling in real time through the first sensing module and the second sensing module, so as to ensure that each of the through holes may be completely filled to form a conductive through hole without voids. Specifically, the first sensing module adopts a light sensing mechanism to assist in determining the bridge formation state in the each of the through holes through light sensing results. In addition, the second sensing module adopts an electrical measurement mechanism to assist in determining at least one of the bridge formation rate, the bridge formation state, the hole filling rate, and the hole filling state in the each of the through holes through electrical measurement results.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.
Patent Application
20250236985
