Electrical processing system for a microelectronic substrate and process

Abstract

System (20) for electroplating a substrate, comprising the following: several chuck assemblies (76), each comprising a chuck (72) and a contact ring (70) positioned between the contact ring (70) and the chuck (72) for clamping a substrate; several electroplating processors (42), each having a rotor (80) adapted to accommodate a chuck assembly; a ring module (40) with a contact ring electroplating device; and a chuck assembly robot (60) which is movable between the ring module (40) and the electroplating processors (42) and has an end effector to engage a chuck assembly.

Description

BACKGROUND OF THE INVENTION

[0001] Microelectronic components are generally fabricated on a semiconductor wafer or other type of substrate or workpiece. In a typical manufacturing process, one or more thin metal layers are deposited on a wafer to produce microelectronic components and / or to provide conductive traces between components.

[0002] The metal layers are generally applied to the wafers via electrochemical plating in an electroplating processor. A typical electroplating processor comprises a container or tray to hold an electroplating solution, one or more anodes in the tray in contact with the electroplating solution, and a head that has a contact ring with multiple electrical contacts that touch the wafer. The front surface of the wafer is immersed in the electroplating solution, and an electric field causes metal ions present in the electroplating solution to dissolve and transfer to the wafer, thus forming a metal layer.

[0003] In so-called "wet contact" processors, the electrical contacts are exposed to the electroplating solution during a plating cycle. Consequently, the metal ions leached from the electroplating solution also transfer to the contacts. However, the contacts may be electroplated at different rates, resulting in some contacts having a relatively larger or smaller surface area in contact with the wafer because the electroplated metal builds up on the contacts over time. This reduces the uniformity of the metal layer electroplated onto the wafer. It can also contaminate the wafer with poorly adhering metal particles that detach from the contacts and deposit on the wafer.To avoid this result, the contacts must be periodically “degalvanized” as part of ongoing maintenance of the reaction apparatus to remove the metal that accumulates on the contacts during a plating cycle.

[0004] Typically, the electroplated coating is removed from the contacts by immersing the contact assembly in the electroplating solution while passing a counter-current electric current through it. The counter-current causes the electroplating cycle to reverse, moving metal away from the contacts and back into the solution. However, the counter-current must be limited to prevent depletion of the electroplating solution. The electroplating process is also limited by the amount of movement that can be allowed the electroplating solution around the contacts. Consequently, the contact electroplating process takes a considerable amount of time. For prior art, reference is made to documents US 2012 / 0037495 A1 and WO 2003 / 087436 A1. Document US 2012 / 0037495A1 describes an electroplating device and document WO 2003 / 087436A1 describes an electropolishing / galvanizing device according to the prior art.

[0005] So-called "dry contact" electroplating processors use a seal to keep the plating solution away from sections of the contacts. The seal must be cleaned periodically to remain effective and prevent contamination of the wafer. The need to maintain the contacts and the seal reduces the throughput or operating efficiency of the electroplating system. Therefore, improved designs are required. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In the drawings, the same reference symbol indicates the same element in each of the views. Fig. Figure 1 is a top view of a machining system. Fig. 2, Fig. 3, Fig. 4 to Fig. 5 are a perspective view, a side view, a front view and a top view of a like in Fig. 1 processor shown. Fig. Figure 6 is a perspective view of the robot arm of Fig. 1, who holds a chuck assembly. Fig. Figure 7 is a side view of the robot moving a chuck assembly to a processor. Fig. Figure 8 is a side view showing the chuck assembly now aligned under the processor head. Fig. Figure 9 is a side view showing the chuck assembly being transferred and attached to the rotor. Fig. 10A and Fig. Figure 10B shows side views of the head with the chuck assembly attached to the rotor, with the head in Fig. 10A driven in and into Fig. 10B is extended. Fig. Figure 11 is an enlarged view of the head, with the rotating components shown in dark grey or black. Fig. Figure 12 is an enlarged sectional view of the chuck attached to the rotor. Fig. Figure 13 is an enlarged alternative sectional view of the chuck assembly attached to the rotor. Fig. 14A is a perspective view of a contact ring. Fig. Figure 14B is an enlarged detail section view of the electrical connection between the contact fingers at the ring contact with the chuck and the rotor. Fig. 14C is a perspective view of a scene like the one in Fig. 14A and Fig. 14B shown electrical contact. Fig. Figure 15 is a perspective view of the front, top, and left side of the head. Fig. Figure 16 is a side view of the head, showing additional elements. Fig. Figure 17 is a side view of the head in a tilted orientation. Fig. Figure 18 is a perspective view of the front, top, and left side of an alternate head. Fig. 19 is a side view of the head of Fig. 18. Fig. Figure 20 is a perspective view of an alternative chuck. Fig. 21 is a sectional view of an alternative rotor designed for use with the one in Fig. The chuck shown in the 20 shown is adapted. Fig. 22A - 22D are sectional views showing a sequence of steps for disassembling the chuck assembly from Fig. 10 from the rotor of Fig. Show 21. Fig. Figure 23 is a top view of an alternative machining system. DETAILED DESCRIPTION OF THE DRAWINGS

[0007] As in Fig. As shown in Figure 1, a processing system 20 comprises modules or subsystems within a housing 22. Wafer or substrate containers 24, such as FOUP (front opening unified pod) containers, can be docked at a loading / unloading station 26 on the front of the housing 22. The subsystems used can vary depending on the specific manufacturing processes performed by the system 20. In the example shown, the system 20 includes a front interface 28, which can provide temporary storage for wafers being moved into or out of the system 20 and optionally provides other functions. If required, a tempering module 30, a rinsing / drying module 32, a ring module 40, and electroplating chambers 42 can be arranged sequentially within the housing 22 behind the front interface 28. Robots move wafers between the subsystems. For example, a wafer robot 48 is positioned to move wafers between the tempering module 30 and the rinsing / drying module 32.A chuck robot 60 is positioned to move chuck assemblies holding a wafer between the ring module 40 and the electroplating chambers 42. In a basic configuration, the system 20 can comprise only one or more electroplating chambers and one ring module 40.

[0008] As in the Fig. 2, Fig. 3, Fig. 4 to Fig. As shown in Figure 5, an electroplating chamber 42 can contain a container or tray 50 containing anodes, electrolyte, and other components, as described, for example, in International Patent Publication WO2012 / 158966. The electroplating chamber or processor 42 also includes a head 52. The tray 50 and the head 52 can be mounted on a frame 54, with a power supply 56 and other auxiliary components also mounted on the frame.

[0009] In a conventional electroplating processor, a contact ring is typically permanently attached to a rotor. As a result, while the contact ring is being degalvanized and / or the contact ring seal (if used) is being cleaned, the processor is essentially idle, as it is not processing any wafers. System 20 overcomes this disadvantage by designing the contact ring to be removable from the processor rotor. This allows the contact ring to be quickly removed and replaced with a previously degalvanized one. The processor idle time is thus significantly reduced.

[0010] With reference back to Fig. 1. Wafers 120 are inserted into and removed from the ring module 40 by means of the wafer robot 48. Inside the ring module 40, contact rings are degalvanized. A wafer is clamped in place by a contact ring on a chuck. The assembly or unit consisting of the wafer, the contact ring, and the chuck is referred to here as the chuck assembly 76. The chuck assembly 76 is moved to a processor 42.

[0011] The Fig. 6, Fig. 7, Fig. 8 to Fig. Figure 9 shows this movement of a chuck assembly 76 by the chuck robot 60. As described below, in the ring module 40, a contact ring 70, which is used in the processor 42, is attached to a chuck 72, with a wafer 120 clamped between them to form a chuck assembly 76. The chuck robot 60 then moves the chuck assembly 76 to a processor 42. As shown in Fig. As shown in Figure 6, the chuck robot 60 can have a semicircular end effector or arm 62 to engage the chuck 72. The rotor 80 of the processor 42 is lifted upwards away from the tray 50. With reference to Fig. 8 The robot 60 advances the chuck assembly 76 into alignment with the rotor 80. As in Fig. As shown in Figure 9, the chuck assembly 76 is then transferred to the rotor 80, with the chuck 72 being securely attached to the rotor, and the robot 60 is withdrawn.

[0012] With the chuck assembly 76 in place on the rotor 80, the processor 42 is ready to process a wafer. The head 52 moves the rotor 80 from the loading / unloading position, which is located in Fig. 10A is shown, downwards to the electroplating position, which is in Fig. Figure 10B shows the wafer 120 (clamped between the chuck and the contact ring) in contact with the electrolyte in the tray 50. Generally, the rotor rotates the wafer during the electroplating process to provide a more uniform electroplated layer. Fig. 11 shows the processor of Fig. 10B, where the rotating elements are shown in black or dark grey for illustrative purposes.

[0013] With regard to Fig. 12. The contact ring 70 can be attached to the chuck 72 via contact ring magnets 102, which exert a magnetic attraction on chuck magnets 104. The chuck 72 can be attached to the rotor magnets 106 in the rotor 80 during the transfer via the force of the chuck magnets 104. As in Fig. As shown in Figure 13, alignment pins 122, which protrude into openings at the top of the chuck, can be used to align the chuck 72 with the rotor 80. The magnets can optionally be omitted, in which case the contact ring and chuck fastenings are made using mechanical elements such as automatic fastening devices or clamps.

[0014] As in the Fig. As shown in Figures 14A to 14C, the contact ring 70 has a large number of individual contact fingers 74 that establish the actual physical and electrical contact with the wafer 120. Electric current flows from the fingers 74 through ring conductors 90 to several radially spaced chuck contacts 132 on the chuck. The chuck contacts 132 contact a metal ring 130 in the rotor when the chuck is attached to the rotor. The metal ring 130 is connected via conductive elements in the head 52 to a power source, typically a cathode.

[0015] The Fig. 15, Fig. 16 to Fig. Figure 17 shows a head design which, in addition to raising and lowering the rotor 80, as in the Fig. As shown in Figures 10A to 10B, the rotor can also be tilted to allow the 120-inch wafer to enter the electrolyte at an angle. In the Fig. 15, Fig. 16 to Fig. In the design shown in Figure 17, the rotor frame 85 is pivoted about head pivot joints 64 by a pivoting actuator 66. As in Fig. As shown in Figure 17, a tilting of the rotor frame 85 corresponding to the wafer 120 causes the rotor 80 to move the wafer 120 at an angle into the electrolyte to improve wetting characteristics and reduce bubble inclusions. Fig. 18 to Fig. Figure 19 shows an alternative head 140 in which the rotor frame is fixed (i.e., movable only vertically) and the rotor 144 is tilted about head pivot joints 142.

[0016] Fig. Figure 20 shows an alternative chuck 150 for use with an alternative rotor 160, which is in Fig. Figure 21 shows the chuck 150 having a slotted plate 152 and an insertion recess 154. The rotor 160 has a clamping bar 166 which is pressed upwards by a spring 164. An actuator 162 in the head is positioned to move the clamping bar 166 downwards against the force of the spring.

[0017] The Fig. Figures 22A to 22D show the chuck removal sequence. Fig. 22A, with the actuator inactive, the spring holds the clamping rod in the upper position. The head 168 of the clamping rod 166 is attached under the slotted plate 152, so that the chuck is securely clamped to the rotor by the force of the spring. In Fig. In step 22B, the actuator is energized, causing the clamping rod to be pushed downwards and the chuck to be separated from the rotor. Fig. In step 22C, the chuck robot 60 moves the chuck laterally, causing the head of the clamping bar to move out from under the slotted plate and into the recess 154. Fig. In step 22D, robot 60 lowers the chuck assembly 76, removes it from the rotor, and moves it to the ring module 40. At the ring module 40, robot 60 places the chuck assembly 76 and picks up a new chuck assembly 76 with an unprocessed wafer. Robot 60 then moves the new chuck assembly 76 to a processor, where it is loaded using the reverse sequence of the steps described in the Fig. The steps shown in sections 22A to 22D are used for loading. The rotors, chucks, and contact rings can be identical (same size and shape) so that the chuck assemblies can be used interchangeably.

[0018] In the ring module, contact rings are degalvanized and contact seals, if present, can be cleaned. Degalvanizing and / or seal cleaning can be performed with the contact ring attached to the chuck. In this type of system, the chuck and the contact ring can be essentially permanently fixed together. Alternatively, a modified contact ring, suitable for treatment and attachment to the head in the same way as the chuck, can be used essentially as a contact ring / chuck combination. In this design, the functional elements of the chuck are contained within the contact ring, eliminating the need for a separate chuck. For example, the contact ring can be provided with an integrated support plate, with contact fingers of the contact ring movable towards and away from the support plate to load and unload a wafer.

[0019] The contact ring can be detached and separated from the chuck during degalvanizing and / or cleaning. In this type of system, each degalvanized contact ring is attached to a chuck, with an unprocessed wafer clamped between them. The resulting chuck assembly 76 is then positioned for pickup by the robot 60. Additionally, returning chuck assemblies 76 are opened in the ring module 40 by a processor 42, i.e., the processed wafer is unclamped and removed for pickup by the wafer robot 48.

[0020] The in Fig. System 20 shown can be used for Damascus copper plating. Fig. Figure 23 is a top view of another system 180 that can be used for wafer level packaging (WLF). System 180 can omit the annealing chamber 30. The spin rinser dryer chambers 32 can be combined with the contact ring station 40 to form a carrier module 182. The carrier module 182 can also include one or more vacuum pre-wetting chamber(s). Compared to the one in Fig. System 20 shown in 1 takes place in the in Fig. In system 180 shown in 23, the wafer clamping / wafer unclamping steps in the carrier module 182 are located more towards the front end of the system than at a more central position as in Fig. 1. The carrier module can be equipped with three spin rinser dryer chambers, two vacuum pre-wetting chambers and two contact ring stations.

[0021] Continuing with reference to Fig.System 182 can have up to 20 grouped metal electroplating chambers 42 for electroplating three different metals, such as copper, nickel, and tin / silver. These metal electroplating chambers can be arranged in a stacked configuration on two levels. The robot and chuck operating sequences described above for use in System 20 can also be used in System 180.

[0022] Thus, novel systems and methods have been demonstrated and described. Various modifications and substitutions can, of course, be made without deviating from the core and scope of the invention. Therefore, the invention should not be limited, except by the following claims and their equivalents. Wafer means a silicon or other semiconductor material wafer, or another type of substrate or workpiece used for manufacturing microelectronic, microelectromechanical, or micro-optical components. The described systems are suitable for use with wafers with diameters of 150, 200, 300, or 450 mm.

Claims

[1] System (20) for electroplating a substrate, comprising: several chuck assemblies (76), each comprising a chuck (72) and a contact ring (70) positioned between the contact ring (70) and the chuck (72) for clamping a substrate; several electroplating processors (42), each having a rotor (80) adapted to accommodate a chuck assembly; a ring module (40) with a contact ring electroplating device; and a chuck assembly robot (60) which is movable between the ring module (40) and the electroplating processors (42) and has an end effector to engage a chuck assembly. [2] System (20) according to claim 1, further comprising a wafer robot (48) to move wafers into and out of the ring module (40). [3] System (20) according to claim 1, wherein the chuck (72) of each chuck assembly (76) has a substantially round plate with multiple electrical contacts extending from a top surface of the chuck (72) of each chuck assembly (76) to the contact ring (70). [4] System (20) according to claim 1, wherein the chuck (72) of each chuck assembly (76) has a substantially round plate with one or more gas passages in a top surface of the chuck (72) of each chuck assembly (76). [5] System (20) according to claim 1, wherein each electroplating processor has a head (52) mounted on a frame (54), and wherein the respective rotor (80) of the electroplating processors (42) is attached to a vertical slide track actuator (162) on the head (52). [6] System (20) according to claim 5, further comprising a tilting actuator for tilting the head (52). [7] System (20) according to claim 1, wherein the contact ring (72) is attached to the chuck (72) of each chuck assembly (76) via magnets (102, 104). [8] System (20) according to claim 1, wherein the chuck (72) of each chuck assembly (76) can be attached to the respective rotor (80) of the electroplating processors (42) via magnets (104, 106). [9] System (20) according to claim 1, wherein the chuck (72) of each chuck assembly (76) has a slotted plate (152), and wherein the chuck (72) of each chuck assembly (76) is attached to the rotor (80) of the electroplating processors (42) via a clamping rod (166) engaging with the slotted plate (152). [10] System (20) according to claim 2, wherein the ring module (40) further comprises a wafer loading device for receiving a wafer (120) from the wafer robot (48) and clamping the wafer (120) between a chuck (72) and a contact ring (70) to form a chuck assembly (72), and a wafer unloading device for removing a machined wafer (120) from a chuck assembly (72) and moving the contact ring (70) of the chuck assembly (72) to the contact ring electroplating device. [11] Methods for processing a wafer, comprising the following: Clamping a first wafer between a first chuck and a first contact ring; Attaching the first chuck to a rotor of an electroplating processor; Processing the wafer by bringing the first wafer into contact with an electrolyte and passing an electric current through the electrolyte; Removing the first chuck from the rotor; Unclamping and removing the first wafer from the first chuck; and Degalvanizing the first contact ring away from the electroplating processor; Clamping a second wafer between a second chuck and a second contact ring; Attaching the second chuck to the rotor of the electroplating processor; and Processing the second wafer by bringing the second wafer into contact with an electrolyte and passing an electric current through the electrolyte while the first contact ring is degalvanized. [12] Method according to claim 11, further comprising bringing the first wafer into contact with an electrolyte by positioning the rotor at an angle to the surface of the electrolyte and lowering the wafer into contact with the electrolyte. [13] Method according to claim 11, further comprising aligning the rotor with the first chuck by rotating the rotor in order to position alignment pins on the rotor via alignment openings in the first chuck. [14] Method according to claim 11, further comprising sealing an upper surface of the first chuck against the rotor. [15] Method according to claim 11, further comprising attaching the first chuck to the rotor via a clamping rod which engages with the first chuck, and drawing the first chuck into engagement with the first rotor. [16] Method according to claim 15, further comprising bringing the clamping rod into a first direction by spring force. [17] Method according to claim 16, further comprising temporarily pressing the clamping rod in a second direction opposite to the first direction in order to compress the spring and release the chuck from the rotor.

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