Adaptive focusing and delivery system for electroplating

Abstract

A system and method for electroplating a workpiece. In one aspect, an apparatus includes a deposition chamber, a workpiece holder adapted to be inserted and removed from the deposition chamber, a shield having a pattern of apertures corresponding to features on the workpiece, a shield holder also adapted to be inserted and removed from the deposition chamber, and a positioning mechanism to position the workpiece in the workpiece holder so that the pattern of apertures on the shield will align with the corresponding features on the workpiece when the workpiece holder and the shield holder are inserted into the deposition chamber.

Description

TECHNICAL FIELD

[0001] The present invention relates to an electrochemical deposition system for depositing metal features onto a workpiece at respective target locations of the workpiece, and a method for electrochemically depositing metal features onto a workpiece at respective target locations of the workpiece. BACKGROUND

[0002] As interconnect critical dimensions become increasingly tighter, spatial and thickness uniformity of features by electrochemical deposition (ECD) is particularly important for many applications. Uniformity of such features can be improved by using a near-patterning shield (CPS) that concentrates current to areas of the substrate where higher current density is needed.

[0003] Large and thin rectangular panels composed of insulating material are increasingly used as substrates for advanced packaging applications in electronic devices. These substrates can be composed of organic laminates or glass that are made using photolithography processes combined with electroplating. The substrates range in thickness from very thin (100-200 pm) to thick (about 2 mm) and rigid. Other substrates used in advanced packaging include relatively rigid silicon discs and more flexible discs made of molding compound or other insulating material. Hereinafter, the term "workpiece" will be used to include such panels, wafers and substrates suitable for ECD processes.

[0004] Figure 1 A known electrochemical deposition system 100 for depositing metal onto target locations of a workpiece is schematically illustrated and described in detail in US 2017 / 0370017. The electrochemical deposition system 100 includes two or more processing modules including at least one electrochemical deposition module disposed on a common platform and configured for depositing one or more metals onto a workpiece. Each electrochemical deposition (ECD) module includes an anode chamber configured to hold a volume of anode electrolyte, a cathode chamber configured to hold a volume of cathode electrolyte, and a separator separating the anode chamber from the cathode chamber. Alternatively, an ECD module can include a single cathode electrolyte bath for electroplating metals that do not benefit from separate anode and cathode electrolyte chambers. The electrochemical deposition system 100 has a load port receiving a set of workpieces, including a loader module 110 for receiving workpieces into the electrochemical deposition system 100 through a load / input station 112 and loading each received workpiece into a respective workpiece holder 125, e.g., a flexible panel holder (PH).

[0005] The system 100 includes a transport mechanism configured to transport the flexible workpiece from the loader module 110 to a given processing module (e.g., an electrochemical deposition module) through its respective workpiece holder 125 and insert the given workpiece into the given processing module. For example, once a workpiece holder 125 designated for processing is loaded with a workpiece, the workpiece holder can be advanced along the processing path 115 (see PH processing path) for pre-processing in one or more pre-processing modules 120 as needed; processing in one or more processing modules 130, 132, 134, 136, 138; and post-processing in one or more post-processing modules 140 as needed. Pre-processing can include, for example, cleaning and / or wetting the workpiece to be processed. Processing can include, for example, depositing a material such as metal onto the workpiece. Meanwhile, post-processing can include, for example, rinsing and / or drying the workpiece.

[0006] The loader / input station 112 portion of the system 100 is part of the system front end where unprocessed substrates are loaded into the workpiece holders, which can also include front opening unified pods (FOUPs - not shown). In single-ended systems, unloading also occurs at the front end of the system. The ECD system 100 is double-ended, with unloading occurring at its back end.

[0007] The unloader module 150 is configured to remove the flexible workpiece from the workpiece holder and transport the workpiece to an unloading port configured to receive a set of workpieces. Once unloaded, the workpiece holder 125 can return along the return path 155 (see PH return path) to the loader module 110 to receive another workpiece. Multiple workpiece holders can be used, with some workpiece holders held in a storage buffer (not shown).

[0008] The electrochemical deposition system 100 also includes a chemical management system 160 for managing the process fluids within one or more processing units (i.e., modules 120, 130, 132, 134, 136, 138, or 140). Chemical management can include, but is not limited to, supply, replenishment, dosing, heating, cooling, circulation, recirculation, storage, monitoring, discharge, abatement, etc. The electrochemical deposition system 100 also includes an electrical management system 170 that can transmit and receive signals according to computer coded instructions to control the movement of the workpiece through the electrochemical deposition system 100 or to control the chemical properties, such as chemical composition, temperature, flow rate, etc., of the plurality of modules 120, 130, 132, 134, 136, 138, 140. In addition, the electrical management system 170 can be configured to apply an electrical current to one or both opposing planar surfaces of a flexible workpiece while the flexible workpiece is held within a given electrochemical deposition module. In doing so, one or both opposing surfaces can be plated with metal and filled with metal for blind and / or through holes.

[0009] A substrate or other workpiece to be processed in such an ECD system can be loaded into a workpiece holder and transported to an ECD module for processing. Figure 2 A known exemplary workpiece holder 125 is shown, which is comprised of flexible contact seals 121 and 122 that clamp the workpiece W so that the workpiece is held in a first plane. The workpiece holder 125 also includes two flexible legs 111 and 113 that are connected to the crossbar 107. Figure 2 The exemplary workpiece holder 125 shown is described in detail in U.S. Patent 10,283,396, which is assigned to the assignee of the present application and incorporated herein by reference. The workpiece holder 125 is adapted to be inserted and removed from a deposition chamber (e.g., processing module 120) while holding the workpiece.

[0010] As is understood in the art, the use of a dielectric shield in ECD with an open area disposed between the anode and the cathode or workpiece to alter the electric field in the vicinity of the workpiece as a whole, thereby modifying the deposition current to achieve uniformity control, e.g., to compensate for end effects or other one-dimensional plating effects.

[0011] A near-pattern shield (CPS), also known as a "current focusing shield", is a dielectric shield close enough to the workpiece to allow uniformity control over the length of a feature pattern. In this document, the terms "near-pattern shield" and "CPS" can be used interchangeably. A near-pattern shield is similar to a photomask in photolithography, and contains a pattern of openings specifically designed for a particular workpiece pattern. The pattern in the CPS concentrates current where it is needed on the workpiece, for example, in the most densely connected areas of features. Since the connected features are a pattern of wires and pads that are repeated at the die level, the CPS provides the ability to improve die-level uniformity, as opposed to prior art far- uniformity shields (FUS) that compensate for workpiece-level current effects.

[0012] Figure 3 An exemplary CPS 200 in the form of a generally planar plate with an aperture pattern formed therein is shown schematically. As shown, the CPS 200 contains a repeating set of aperture patterns 220 for use with a rectangular workpiece. Each aperture pattern 220 on the CPS 200 corresponds to a single die on the workpiece, such that the arrangement of aperture patterns 220 on the CPS 200 is similar to the array of dies on the workpiece, i.e., the aperture patterns substantially correspond to the target locations of features on the workpiece. During processing by the ECD module, the near-pattern shield is held by a shield holder (not shown in the drawings) in order to be aligned with the substrate. Figure 3

[0013] Figure 4 An exploded view of the ECD module 503 with a pair of shield holders 320 is shown, each of which is used to position a respective CPS 200 in alignment with the workpiece holder 125, such that each shield holder 320 holds its respective CPS 200 in a second plane that is substantially parallel to a first plane (of the workpiece). The ECD module housing 301 and anode assembly 302 are also shown. The anode assembly 302 can consist of a set of individually controllable anodes (not shown) connected to a multi-channel power supply by current taps 303. A second anode assembly 302 can be mounted on the back of the housing 301 for plating the reverse side of the workpiece W when the workpiece holder 125 is inserted into the ECD module 503. The ECD module 503 also has actuators (not shown) to move the workpiece holder 125 and the shield holder 320 in the X and Y directions, and a Z actuator to move the workpiece holder 125 and the shield holder 320 in the Z direction. Figure 4 ​A shield holder 320 is provided for setting the distance between each CPS 200 and the workpiece W so as to properly focus the electric field between the anode assembly 302 and the workpiece W. The shield holder 320 is adapted to be inserted and removed from the deposition chamber while holding the CPS 200. Details of the shield holder 320, the ECD module 503, and the actuation of the shield holder 320 for close positioning to the workpiece holder 125 after insertion of the ECD module 503 are described in U.S. Patent Application 16 / 516,714 filed by the present applicant, which is incorporated herein by reference.

[0014] During processing, the near-patterned shield must be carefully aligned to the substrate. The CPS 200 must be held in place so that its apertures 220 are aligned to the corresponding pattern on the target location on the workpiece. Furthermore, there is an optimal distance between the CPS 200 and the workpiece for properly focusing the electric field.

[0015] Figure 5 An isometric cutaway view of the ECD module 503 is shown schematically, showing the workpiece holder 125 and the shield holder 320 after insertion. An actuator 325 is provided at the inner surface of the housing 301, which is operable to move the chuck frame 321, the translation rails 322, the CPS 200, and the agitator plate 312 relative to the housing 301, thereby changing the distance between the CPS 200 and the workpiece W. The actuator 325 can be, for example, a pneumatic, mechanical, or electric type actuator.

[0016] Figure 6 The uniformity of the plating height of the CPS 200 connection features is shown as a function of the gap distance between the CPS 200 and the workpiece W. Three different CPS curves are given for different ratios of the aperture 220 size to the feature size on the workpiece W. For this example, the optimal distance between the CPS 200 and the workpiece W is approximately 4mm to 6mm, depending on the shrinkage factor (SF) chosen. For an optimal shrinkage factor of 0.7, the optimal distance between the CPS 200 and the workpiece W is approximately 4mm. Figure 6 It is shown that the uniformity decreases if the distance from the CPS 200 to the workpiece W is closer or farther than the optimal distance. Figure 6 An equivalent curve for a far-uniformity shield (FUS) employing a regularly spaced aperture pattern is also shown. Figure 6 The curve in shows that the deposition uniformity of the FUS is less sensitive to the distance between the shield and the workpiece compared to the CPS, but also results in a larger standard deviation of the feature height, i.e., a poorer uniformity at the die level. The FUS is designed to affect the workpiece-level uniformity, not the die-level uniformity.

[0017] In known ECD tools, the near-pattern shields are stored outside the ECD tool and are manually installed. Preferably, various shields are stored within the ECD tool and the required pattern for a specific workpiece W is provided on demand for insertion into the ECD module without human intervention. This tool configuration will minimize tool down time and reduce the likelihood of installation errors.

[0018] The near-pattern shields in the ECD unit must be precisely aligned in all three dimensions to their corresponding workpiece pattern in order to achieve good deposition uniformity. In prior art tools, the alignment of the shields to the substrate is not precise enough to achieve the required level of uniformity, especially when the critical dimensions of the workpiece features become smaller.

[0019] In order to achieve optimal current focusing, the distance between the near-pattern shield and the workpiece is usually set by the distance between the shield holder and the workpiece holder. For this reason, the distance between the workpiece surface and the CPS can depend on the thickness of the workpiece itself. This distance can also depend on the degree of curvature of the workpiece once it is installed in the workpiece holder. Prior art electroplating systems do not take into account these workpiece-related details when setting the distance between the focusing shield and the workpiece.

[0020] The present invention solves these problems by providing an automated system that delivers the required near-pattern shield for a specific workpiece to the electro-deposition module prior to processing and subsequently ensures optimal alignment and spacing between the workpiece and the shield in the electro-deposition process. SUMMARY

[0021] According to a first aspect of the present invention, there is provided an electrochemical deposition system for depositing metal features onto a workpiece at respective target locations of the workpiece, comprising:

[0022] a deposition chamber adapted to receive, in use, an electroplating solution;

[0023] a workpiece holder for holding a workpiece in a first plane, and adapted to be inserted into and removed from the deposition chamber while holding the workpiece;

[0024] a shield comprising a substantially planar plate having an aperture pattern formed therein, the aperture pattern corresponding, in use, substantially to the target locations;

[0025] a shield holder for holding the shield in a second plane substantially parallel to the first plane, the shield holder being adapted to be inserted into and removed from the deposition chamber while holding the shield; and

[0026] a positioning mechanism for adjusting the position of the workpiece within the first plane, wherein the positioning mechanism is operable to position the workpiece so that the target positions are substantially aligned with the aperture pattern when the workpiece holder and the shield holder are inserted into the deposition chamber.

[0027] Advantageously, the electrochemical deposition system comprises a control system, and the positioning mechanism is configured to adjust the position of the workpiece within the first plane under control of the control system. In particular, the positioning mechanism can be configured to adjust the position of the workpiece within the first plane based on data provided by the control system, for example from a computer model generated by the control system, or using measured data stored in a database of the control system or otherwise obtained directly. The data stored in the control system can be based on a model of the physical system or on measured position data. Positioning can be achieved by using one or more actuators operable to move the workpiece to achieve such alignment, or by using a transport technique with or without a combination of actuators when inserting the workpiece into the workpiece holder.

[0028] According to a second aspect of the application, there is provided a method for electrochemically depositing metal features onto a workpiece at respective target positions of the workpiece, comprising:

[0029] i) providing a deposition chamber adapted to receive, in use, an electroplating solution;

[0030] providing a workpiece holder for holding a workpiece in a first plane, and adapted to be inserted into and removed from the deposition chamber; and

[0031] providing a shield comprising a substantially planar plate having an aperture pattern formed therein, the aperture pattern corresponding substantially, in use, to the target positions;

[0032] ii) inserting the shield into the deposition chamber;

[0033] iii) positioning the workpiece relative to the workpiece holder within the first plane;

[0034] iv) loading the positioned workpiece into the workpiece holder;

[0035] v) inserting the loaded workpiece holder into the deposition chamber; and

[0036] vi) depositing metal features onto the workpiece;

[0037] wherein in step iii) the workpiece is positioned in the first plane relative to the workpiece holder such that the target position is substantially aligned with the aperture pattern when the workpiece holder and the shield are inserted into the deposition chamber.

[0038] Other specific aspects and features of the application are listed in the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0039] The application will now be described with reference to the drawings (not to scale) in which:

[0040] Figure 1 A known electrochemical deposition system is schematically illustrated.

[0041] Figure 2 A known workpiece holder is schematically illustrated.

[0042] Figure 3 A known rectangular near-field pattern shield is schematically illustrated from above.

[0043] Figure 4 A known electrochemical plating module is schematically illustrated as well as an exploded isometric view of a known workpiece holder and two shield holders.

[0044] Figure 5 An isometric cut-away view of a known electrochemical plating module is schematically illustrated showing the workpiece holder and shield holders inserted.

[0045] Figure 6 A plot of the uniformity of the rectangular near-field pattern shield and the far uniformity shield of Figure 3 vs. shield-workpiece gap is shown.

[0046] Figure 7 An electrochemical deposition system according to an embodiment of the application is schematically illustrated.

[0047] Figure 8 An input / output module, loader module and workpiece holder storage module according to an embodiment of the application are schematically illustrated from above.

[0048] Figure 9 A perspective view of a workpiece loader according to an embodiment of the application is schematically illustrated in one configuration.

[0049] Figure 10 A perspective view of a workpiece loader according to an embodiment of the application is schematically illustrated in another configuration.

[0050] Figure 11 A workpiece loader according to an embodiment of the application is schematically illustrated from above.

[0051] Figure 12 A workpiece loader according to an embodiment of the application is shown schematically from the side.

[0052] Figure 13 A transfer arm portion of a workpiece loader according to an embodiment of the application is shown schematically from above.

[0053] Figure 14 A transfer arm portion of a workpiece loader according to an embodiment of the application is shown schematically from the front.

[0054] Figure 15 A perspective view of a portion of a workpiece loader according to an embodiment of the application is shown schematically from above.

[0055] Figure 16 A perspective view of a portion of a workpiece loader according to an embodiment of the application is shown schematically from below.

[0056] Figure 17 A conveyor for conveying workpieces and proximate pattern shield holders according to an embodiment of the application is shown schematically from the side.

[0057] Figure 18 A conveyor for conveying workpieces and proximate pattern shield holders according to an embodiment of the application is shown schematically from the front.

[0058] Figure 19 An enclosed conveyor portion of a conveyor for conveying workpieces and proximate pattern shield holders according to an embodiment of the application is shown schematically from the front.

[0059] Figure 20 A plating tool storage module for storing proximate pattern shields according to an embodiment of the application is shown schematically from above. DETAILED DESCRIPTION

[0060] For the sake of holding consistency and clarity, in the following description the same reference numbers will stand for the same components.

[0061] Figure 7 A plating tool 500 is shown schematically having an input / output module 510, a loader / unloader module 530, a workpiece holder storage module 580, processing modules 501-505, a proximate pattern shield storage module 590, a conveyor support area 570, a maintenance support area 506, an electrical and chemical system area 507, and a workpiece holder cleaning module 508. The tool 500 is a single ended tool, in which unprocessed substrates are introduced into the tool and processed substrates are removed from the tool in the same input / output front end module 510. Although the tool 500 is shown as a single ended tool, it is contemplated that the tool 500 can be a double ended tool, in which unprocessed substrates are introduced into the tool and processed substrates are removed from the tool in different input / output front end modules 510. Figure 7Five process modules are shown, but the tool 500 can have any number of process modules depending on the specific processes to be performed, e.g., the number of different metals to be plated, the number of pre-plating and post-plating processes required, and the number of duplicate modules used in parallel to increase tool throughput.

[0062] The workpiece holder storage module 580 is used to store workpiece holders 125 that are not in use. Local conveyors (not shown) transport workpiece holders 125 from the storage area 580 to the loader / unloader 530 for use. The conveyor support area 570 provides mechanical, electrical, and fluid support to two or more conveyors 571 (see Fig. 6) that overhang the loader / unloader 530, the process modules 501-505, and the CPS storage area 590. The electrical and chemical system area 507 houses the electrical distribution system and fluid handling system for all other modules. The maintenance support area 506 allows support personnel to access equipment in the electrical and chemical system area 507 and all electrical and fluid connections in the process modules 501-505. The workpiece holder cleaning module 508 includes equipment to clean workpiece holders 125 when they are not in use to process workpieces. Figure 17 ) provides mechanical, electrical, and fluid support to two or more conveyors 571 (see Fig. 6) that overhang the loader / unloader 530, the process modules 501-505, and the CPS storage area 590. The electrical and chemical system area 507 houses the electrical distribution system and fluid handling system for all other modules. The maintenance support area 506 allows support personnel to access equipment in the electrical and chemical system area 507 and all electrical and fluid connections in the process modules 501-505. The workpiece holder cleaning module 508 includes equipment to clean workpiece holders 125 when they are not in use to process workpieces.

[0063] The process flow for an unprocessed workpiece in the tool 500 begins with its transfer from the input / output module 510 by a robot to the loader / unloader module 530, where the workpiece W is loaded into a workpiece holder 125. The loaded workpiece holder is then transported using a conveyor mechanism to a series of pre-processing modules 501-502 for wet processing steps, e.g., pre-cleaning, pre-rinsing, and chemical activation. The loaded workpiece holder 125 is then transported to a processing module 503 or 504 for plating. After plating, the loaded workpiece holder 125 is transported to a processing module 505 for further processing steps, e.g., final rinsing and drying. After final rinsing and drying, the loaded workpiece holder 125 is transported to the loader / unloader module 530, where the workpiece W is unloaded from the workpiece holder 125. The processed workpiece W is then transported to the input / output module 510 for storage until all workpieces in the current batch have been processed.

[0064] Figure 8 The input / output module 510, the loader module 530, and the workpiece holder storage module 580 are shown schematically. The X, Y, and Z axes of a Cartesian coordinate system are shown, with the Z axis extending vertically upward and the X and Y axes extending orthogonally to each other in the horizontal plane. For ease of illustration, Figures 9 to 14All show these axes. The input / output module 510 includes at least two front opening wafer containers (FOUPs) 511 for storing workpieces, including unprocessed workpieces, such as unprocessed workpieces W and W’, and processed workpieces Wp and Wp’, wherein, Figure 8 Three FOUPs are shown. The input / output module 510 also includes a robot 512 configured to run along a robot track 515, the robot 512 including an end effector 514 that can be rotated about a vertical axis between two rotational directions, wherein, in a first rotational direction, as shown, Figure 8 the end effector 514 is pointed to the right, while in a second rotational direction, the end effector 514 is pointed to the left. The loader module 530 includes a loader 535 that includes a positioning mechanism that includes a positioning table 540 and a pivot-rotating opener or “PRO” 550, which will be described in more detail below. The workpiece holder storage module 580 includes a carousel 583 adapted to temporarily store a plurality of workpiece holders 125 therein in an array, and a local conveyor 586 having a pick arm 582 capable of loading a workpiece holder 125 from a manual ejector area 585. The local conveyor 586 is arranged to convey an empty workpiece holder 125 from the carousel 583 to a location where the conveyor 571 can convey the workpiece holder 125 to the loader / unloader module 530 for insertion into the PRO 550.

[0065] The robot 512 is arranged to transfer a single unprocessed workpiece W from a FOUP 511 to a transfer table 560 (see Figure 9), while the robot 512 is in the second rotational direction and aligned with the expected FOUP 511 by lateral motion along the robot track 515, the end effector 514 is used to grab the unprocessed workpiece W from the FOUP 511, the robot 512 is rotated to the first rotational direction and aligned with the transfer table 560 by lateral motion along the robot track 515, and then the unprocessed workpiece W is placed to the transfer table 560. Likewise, the robot 512 is arranged to perform similar operations in reverse to return the processed workpiece Wp from the transfer table 560 to the FOUP 511 after processing. For example, the end effector 514 can comprise a lightweight, rigid material, such as carbon fiber composite. As shown, the end effector 514 can comprise mechanical features for gripping the edges of the workpiece W. Alternatively, the end effector 514 can comprise other devices, such as vacuum cups or Bernoulli gas jets, to grip the backside of the workpiece W and hold it flat for subsequent loading operations. Alternatively, the robot 512 can comprise two end effectors 514 in order to maximize system throughput when replacing the unprocessed workpiece with the processed workpiece by a so-called “give-and-get” operation, and the robot 512 can be connected to multiple links 513 to have sufficient distance to place the workpiece W onto the transfer table 560.

[0066] Figure 9 A perspective view of the workpiece loader 535 is shown schematically, including the PRO 550, the positioning table 540, and the workpiece transfer table 560, all mounted on a support frame 539. The PRO 550 is provided in a horizontal position, rotated about an axis 551 by a motor drive 553 through a pivot arm 552. The upper end of the PRO 550 has two slots 554 and 554’ formed therein, with edge guides 555, configured to receive respective workpiece holders 125 (not shown in the middle). When the PRO 550 is in this horizontal position, the workpiece holders 125 can be inserted into the slots 554 and 554’ from above by a conveyor 571. The workpiece transfer table 560 includes an upper transfer arm 561 and a lower transfer arm 562. As shown, the upper transfer arm 561 carries an unprocessed workpiece W prior to alignment in the positioning table 540. As shown, the transfer table 560 is in a lower position for transferring workpieces between the input / output module 510 and the loader / unloader module 530 by the upper transfer arm 561. Figure 9 A perspective view of the workpiece loader 535 is shown schematically, including the PRO 550, the positioning table 540, and the workpiece transfer table 560, all mounted on a support frame 539. The PRO 550 is provided in a horizontal position, rotated about an axis 551 by a motor drive 553 through a pivot arm 552. The upper end of the PRO 550 has two slots 554 and 554’ formed therein, with edge guides 555, configured to receive respective workpiece holders 125 (not shown in the middle). When the PRO 550 is in this horizontal position, the workpiece holders 125 can be inserted into the slots 554 and 554’ from above by a conveyor 571. The workpiece transfer table 560 includes an upper transfer arm 561 and a lower transfer arm 562. As shown, the upper transfer arm 561 carries an unprocessed workpiece W prior to alignment in the positioning table 540. As shown, the transfer table 560 is in a lower position for transferring workpieces between the input / output module 510 and the loader / unloader module 530 by the upper transfer arm 561.

[0067] Figure 10 A perspective view of the workpiece loader 535 is shown schematically, including the PRO 550, the positioning table 540, and the workpiece transfer table 560, all mounted on a support frame 539. The PRO 550 is provided in a horizontal position, rotated about an axis 551 by a motor drive 553 through a pivot arm 552. The upper end of the PRO 550 has two slots 554 and 554’ formed therein, with edge guides 555, configured to receive respective workpiece holders 125 (not shown in the middle). When the PRO 550 is in this horizontal position, the workpiece holders 125 can be inserted into the slots 554 and 554’ from above by a conveyor 571. The workpiece transfer table 560 includes an upper transfer arm 561 and a lower transfer arm 562. As shown, the upper transfer arm 561 carries an unprocessed workpiece W prior to alignment in the positioning table 540. As shown, the transfer table 560 is in a lower position for transferring workpieces between the input / output module 510 and the loader / unloader module 530 by the upper transfer arm 561. Figure 9 A perspective view of the workpiece loader 535 is shown schematically, including the PRO 550, the positioning table 540, and the workpiece transfer table 560, all mounted on a support frame 539. The PRO 550 is provided in a horizontal position, rotated about an axis 551 by a motor drive 553 through a pivot arm 552. The upper end of the PRO 550 has two slots 554 and 554’ formed therein, with edge guides 555, configured to receive respective workpiece holders 125 (not shown in the middle). When the PRO 550 is in this horizontal position, the workpiece holders 125 can be inserted into the slots 554 and 554’ from above by a conveyor 571. The workpiece transfer table 560 includes an upper transfer arm 561 and a lower transfer arm 562. As shown, the upper transfer arm 561 carries an unprocessed workpiece W prior to alignment in the positioning table 540. As shown, the transfer table 560 is in a lower position for transferring workpieces between the input / output module 510 and the loader / unloader module 530 by the upper transfer arm 561.Figure 9 In contrast, the illustrated transfer station 560 is slightly elevated in position for transferring workpieces between the input / output module 510 and the loader / unloader module 530 by way of the lower transfer arm 562. When the workpiece holder 125 in the slot 554' is in position below the slot 554 (not visible in the figure), the transfer arms 561 and 562 can be used to replace a processed workpiece with an unprocessed workpiece. During the transfer of the processed workpiece from the slot 554 to the input / output station 510 by way of the link 513, the PRO 550 is rotated 180° into the reverse vertical position (not shown in the figure) so that the other slot 554' is ready for the replacement of the processed workpiece with an unprocessed workpiece. This sequence of steps will be described in more detail below. Figure 10

[0068] Figure 11 The workpiece loader 535 is shown schematically from above with the PRO 550 in its first horizontal configuration. The shown PRO 550 has the workpiece holder 125 inserted into the slot 554, which, as shown, is in a position where the workpiece holder 125 is to the right of the slot 554'. The workpiece holder 125 has a pick-up feature 556 which cooperates with a corresponding pick-up feature (not shown) in the conveyor 571 to allow the workpiece holder 125 (when loaded with a workpiece W) to be lifted out of the slot 554 and conveyed to any of the modules 501-505 as desired. Figure 11 The robot 512 is also shown with the workpiece W held by the end effector 514 placed on the transfer arm 561 below the positioning station 540. After placement into the positioning station 540 by way of the transfer arm 561, the workpiece W can be precisely positioned relative to the positioning frame 541 by appropriate actuation of the positioning actuators 546 attached to the positioning frame 541. Alternatively, during insertion, the actuators 546 can position the workpiece W parallel to the Y-axis while the end effector 514 can position the workpiece W parallel to the X-axis relative to the workpiece holder 125. Alternatively, the end effector 514 can position the workpiece W parallel to both the X-axis and the Y-axis during insertion into the workpiece holder 125.

[0069] Figure 12 The workpiece loader 535 is shown schematically from the side with the PRO 550 in its second configuration, i.e. with the workpiece holder 125 inserted into the slot 554 in the vertical direction. The elongated actuator 567 is attached to the PRO 550 and contains the bladder opener 566 to effectuate the contact seals 121, 122 (see Figure 2 ​activation of the PRO 550. Suitable actuation members 567 and bladder activators 566 are described in detail in U.S. Patent 10,283,396, which is assigned to the assignee of the present application and incorporated herein by reference. The PRO 550 requires one bladder activator per contact seal bar. A workpiece holder 125 adapted to hold one workpiece includes two contact seal bars and requires two activators 566, while a workpiece holder 125 adapted to hold two workpieces includes four contact seal bars and thus requires four activators 566.

[0070] Each bladder activator 566 is inflatable to allow unloading of processed workpieces Wp by the lower transfer arm 562 and loading of unprocessed workpieces W by the upper transfer arm 561. As shown, the transfer station 560 includes the upper transfer arm 561, the lower transfer arm 562, a vertical drive 664, and a horizontal drive 665 on which the workpieces W are supported. The vertical and horizontal drives 664 and 665 are motorized and can be operated to vertically and horizontally position the transfer arms 561 and 562, respectively, relative to the positioning station 540 and the workpiece holder 125. Each of the upper and lower transfer arms 561 and 562 can function as a "chuck" of the workpiece thereon, i.e., to provide stable and flat support of the workpiece. Such chucking is switchable, e.g., if vacuum chucking is used, a vacuum source (not shown) can be switchably connected to each transfer arm 561, 562, while a connection (not shown) to a positive pressure source is made to allow the workpiece to float on an inert gas or compressed dry air, optionally, during positioning.

[0071] Figure 13 The upper transfer arm 561 is shown schematically from above for loading workpieces W into the holder 125 within the PRO 550. The transfer arms 561 and 562 have similar features for grasping the workpiece as the end effector 514, i.e., the upper and lower transfer arms 561 and 562 can include mechanical features for grasping the edges of the workpiece W, or alternatively, they can include vacuum cups or suction cups or Bernoulli gas jets to grasp the backside of the workpiece W and hold it flat for the subsequent loading operation, in particular for loading the workpiece W into the workpiece holder 125.

[0072] In Figure 13In the specific embodiment shown, the upper transfer arm 561 may include a frame 563, a suction cup 564, and a vacuum fitting 565. The frame 563 may be made of, for example, aluminum, carbon composite material, or other rigid lightweight material, and as shown, includes a first outer arm and a second outer arm 569 parallel to each other, and an inner arm 568 arranged parallel thereto, the inner arm being shorter than the first and second outer arms 569. The suction cup 564 may have multiple folds and sufficient compliance to allow vacuum clamping of the workpiece W even with significant bending. The upper transfer arm 561 may also include a separate switchable vacuum connector (not shown) that maintains a vacuum on the outer arm 569 while having no pressure or only a slight positive pressure on the inner arm 568.

[0073] Figure 14 The upper transfer arm 561 is schematically shown in a cross-sectional side view. The upper transfer arm 561 includes a frame 563, a suction cup 564, and a vacuum fitting 565 on which the workpiece W is located. The vacuum fitting 565 can be switchably connected to a vacuum source (not shown) to vacuum-clamp the workpiece W via the suction cup 564. The fitting 565 can also be switchably connected to a positive pressure gas source (not shown) to allow the workpiece W to float on an air cushion during positioning. A cavity 589 is provided within the frame 563, providing fluid communication between the vacuum fitting 565 and the suction cup 564.

[0074] Figure 15 and Figure 16 A perspective view of the positioning stage 540 is schematically shown from both above and below. The positioning stage 540 includes a positioning frame 541 in which the workpiece W is located and supported by an upper transfer arm 561 (not shown). The positioning stage 540 is supported by a bracket 545. A sensor crossbar 544 extends through the positioning frame 541 and carries multiple ultrasonic positioning sensors 543. A charge-coupled device (CCD) positioning camera 542 is also mounted on the positioning frame 541.

[0075] The CCD positioning camera 542 is operable to control the actuation of the positioning actuator 546 based on observation of a reference mark (not shown) provided on the workpiece W, thereby adjusting the positioning of the workpiece W within the positioning frame 541. Preferably, the ultrasonic positioning sensors 543 are capable of resolving the distance between each sensor 543 and the workpiece W with a resolution of at least 0.3 mm. The multiple ultrasonic sensors 543 attached to the positioning frame 541 can be used to ensure that the workpiece W is both flat and well held by the upper transfer arm 561 before being loaded into the PRO 550 (e.g., see...). Figure 12). As shown, two ultrasonic sensors 543 are supported by a sensor crossbar 544, and these sensors can be used to measure any degree of curvature of the workpiece W. This information can be used to determine the proper position of the CPS shield 200 relative to the surface of the (possibly curved) workpiece W in the ECD module 503. The workpiece curvature can be measured when the workpiece gripping function of the transfer arm 561 is closed. The workpiece curvature can be measured in a similar state as in the holder 125, for example, by gripping the workpiece W using only the suction cups 564 on the outer arm 569 (see Figure 13 ) while maintaining zero pressure or slight positive pressure on the suction cups 564 of the central arm 568.

[0076] Various commercially available ultrasonic sensors can be suitable for the sensors 543, including, by way of example only, the "UNDK" series ultrasonic distance sensors available from the Baumer Company, Inc. of Southington, Connecticut. The CCD positioning camera 542 is capable of locating fiducial marks and panel edge locations with 50 μιη or higher resolution. CCD cameras with the requisite resolution include the "FLIR" high performance cameras available from Edmunds Optics, Inc. of Barringto n, New Jersey, by way of example only. Preferably, the positioning actuator 546 is a linear stepper motor with a positioning accuracy of 50 μιη or higher, such as, by way of example only, the high performance "G Series" actuators available from Hayden Kerk / Ametek of Waterbury, Connecticut.

[0077] Figure 17 A conveyor 571 is shown schematically from the side, which is used to convey the workpiece holders 125 from the loader / unloader module 530 to the processing modules 501-505 one at a time, and which is used to convey the shield holders 320 from the shield holder storage module 590 to the processing modules 501-505. The conveyor 571 includes a wheeled cart 575, a conveyor vertical positioner 573, and an enclosed conveyor 572.

[0078] The wheeled cart 575 rides on a conveyor track 574 and is driven along the conveyor track 574 by a motor assembly 579, which extends along the length of the conveyor support area 570. The conveyor track 574 can support multiple conveyors 571 to allow multiple workpiece holders 125 to be conveyed at a time, to increase throughput, or to allow shield holders 320 to be replaced in the ECD module 503 while workpieces are being processed in the processing modules 501, 502, 504, and / or 505.

[0079] The conveyor vertical positioner 573 includes a coiled belt shaft 577 driven by a vertical winding motor 576. The enclosed conveyor 572 includes a drop block 578 connected to the coiled belt shaft 577 by a metal lifting belt 581. The drop block 578 includes a lifting clamp 588 that, when actuated, clamps the pick feature 556 of the workpiece holder 125.

[0080] Figure 18 The conveyor 571 is shown schematically from the front. A connector spool 587 attaches the conveyor vertical positioner 573 to the enclosed conveyor 572 and provides conduit for electrical cables and gas lines, e.g., to purge the enclosed conveyor 572 with nitrogen gas during conveyance. The enclosed conveyor 572 includes a guide feature 585 that guides the drop block 578 during drop and pick operations, and a lower cover 583 that can be activated to close during conveyance and to open during drop and pick. The enclosed conveyor 572 can include an RFID reader 584 to identify workpiece holders 125 (which typically include RFID tags) and / or shield holder 320 containing RFID tags as they are moved out of the processing modules 501-505 and the CPS storage area 590.

[0081] Figure 19 The enclosed conveyor 572 is shown schematically from the front. The lifting clamp 588 of the drop block 578 grips the lifting feature 556 of the shield holder 320 for conveyance from the shield holder storage module 590 to the ECD module 503.

[0082] Figure 20 The shield storage module 590 is shown schematically from above for storing a plurality of shield holders 320, each holding a respective CPS 200 when not in use in the processing modules 501-505. The shield storage module 590 includes a plurality of storage bays 594 having features (not shown) that physically support and position respective shield holders 320. The shield storage module 590 also includes an extractor platform 593 for manually loading and unloading shield holders 320 into the shield storage module 590, and an overhead conveyor 597 supported on a transport rail 596 to convey shield holders 320 from the extractor platform 593 to a target storage bay 594. The shield storage module 590 also includes a conveyor handoff platform 591 connected to the overhead conveyor 597 for transporting shield holders 320 to and from the processing modules 501-505. During pick up of a shield holder 320 by the overhead conveyor 597, the identity of the shield holder 320 holding a CPS 200 can be verified by reading an RFID tag 598 located within the shield holder 320 using an RFID reader.

[0083] The system described above also comprises a control system (not explicitly shown) for enabling control of the above described apparatus. The control system can for example comprise a suitably programmed (whether embodied in hardware, software and / or running a cloud-based application) computer, computing device or similar processor. The control system can be located at or within the main apparatus coverage area, or remotely. As mentioned above, the positioning mechanism is configured to adjust the position of the workpiece under control of the control system. In particular, the positioning mechanism can be configured to adjust the position of the workpiece in accordance with data provided by the control system, for example in accordance with a computer model generated by the control system, or using measurement data stored in a database of the control system or other directly acquired data. This data relates to the physical position of the mask in the processing unit, including the position of the apertures thereon, and the pattern of target positions of the workpiece being positioned, so that the positions of the pattern of target positions and the aperture pattern of the mask can be matched to ensure alignment between the two once the workpiece holder and mask holder have been inserted into the deposition chamber. For example, such a database can hold data obtained from a Gerber file regarding the target positions of the workpiece or equivalent data relating to the workpiece, or equivalent data obtained from direct measurement of the target positions marked on the workpiece. It can also include data regarding the optimal focal distance between the workpiece and the mask, data regarding various mask configurations and the relationship between stirring rate, plating rate, plating uniformity and workpiece bowing.

[0084] Processing steps

[0085] The main processing steps of a method for improving the uniformity of electroplated deposition of features on a workpiece will now be set out, in particular for workpieces for which spatial and thickness uniformity is particularly critical.

[0086] Two sets of processing steps are set out here, one for the CPS 200 and the second for the workpieces W and W’. The two sets of processing steps can be asynchronous, i.e. the transfer of the workpieces W to the FOUP 511 can occur before, during or after the preparation of the CPS 200. Likewise, the transfer of the workpieces W to the transfer stage 560 can occur before, during or after the selection and delivery of the mask 200, provided that there is a CPS 200 in the ECD module 503 during the ECD processing of the workpiece holder 125.

[0087] The following steps describe operations that enable the holding of two workpieces W and W’ in a workpiece holder 125 comprising four contact seals. For workpiece holders 125 configured to hold only a single workpiece W, the workpiece processing step 5 does not apply.

[0088] CPS processing steps:

[0089] 1. Preparing the tool with near pattern shields 200: At least two CPS 200, possibly including various aperture patterns, are loaded into their respective shield holder 320 and manually stored in their respective storage bay 594 using the ejector platform 593 and overhead conveyor 597.

[0090] 2. Selecting a CPS 200 from the list of available CPS in the shield storage module 590: A particular CPS 200 is selected because the repeating set of aperture patterns 220 on that particular shield corresponds to the target locations of the desired plating features on the workpiece W.

[0091] 3. Transporting the CPS 200 from the shield storage module 590 to the ECD processing module 503: The shield holder 320 with the CPS 200 is transported from its storage bay 594 to the conveyor handoff platform 591 using the overhead conveyor 597. The identity of the CPS 200 can be confirmed by reading the RFID tag 598. The shield holder 320 with the CPS 200 is conveyed to the ECD processing module 503 using the conveyor 571. The shield holder 320 is inserted into the processing module 503 using the drop block 578. This step can be repeated for a second CPS to plate both sides of a workpiece, or to plate a single side of two workpieces simultaneously.

[0092] 4. Returning the CPS 200 from the ECD processing module 503 to the shield storage module 590: Once the operator indicates that a different pattern shield is required in the ECD module 503, the CPS 200 is transported to the storage module 590. The CPS processing steps 1-3 are then repeated for a CPS 200 with a different aperture pattern 220.

[0093] Workpiece processing steps:

[0094] 1. Loading an unprocessed workpiece W: The robot 513 uses the end effector 514 to transport an unprocessed workpiece W from the FOUP 511 to the overhead conveyor arm 561 of the conveyor table 560. Vacuum is applied to the suction cup 564, lifting the workpiece W into the positioning stage 540, slightly below the frame 541, in vertical alignment with the positioning actuator 546.

[0095] 2. Position the workpiece W in the workpiece holder 125: the vacuum to the port 565 of the upper transfer arm 561 is turned off, and a slight positive pressure can be applied to allow the workpiece W to float freely on the suction cup 564 of the upper transfer arm 561. Using the image from the CCD positioning camera 542 of the fiducial image on the workpiece W, the positioning actuator 546 positions the workpiece W on the upper transfer arm 561 so that after step 7, the target position of the features on the workpiece W will be aligned with the corresponding holes in the shield 200. The data to determine the proper position can be provided by the control system and based on a computer model of the system, or can be determined experimentally and stored in a database. As the workpiece W is positioned, the suction cup 564 in the outer arm 569 of the upper transfer arm 561 is actuated to clamp the workpiece W to the upper transfer arm 561. Before applying vacuum to the suction cup 564 of the center arm 568, the curvature of the workpiece W can be measured using the ultrasonic sensor 543 and stored in a database.

[0096] 3. The PRO 500 is pivoted to the horizontal position to enable access to the workpiece holder 125. Vacuum is applied to the port 565 of the lower transfer arm 562 to clamp the workpiece. The bladder opener 555 is actuated to open the contact seals 121 and 122. The lower transfer arm 562 removes the workpiece Wp from the workpiece holder 125.

[0097] 4. Load an unprocessed workpiece W into the workpiece holder 125: the bladder opener 566 in the slot 554 is activated to inflate, opening the contact seals 121, 122 in the workpiece holder 125. The workpiece W is then inserted into the open workpiece holder 125 using the upper transfer arm 561. The bladder opener 566 is then deactivated before the vacuum clamp of the workpiece W on the upper transfer arm 561 is removed, thereby ensuring that the workpiece W is properly positioned when inserted into the ECD module 503.

[0098] 5. Repeat the positioning and loading of an unprocessed workpiece W’: the robot 513 uses the end effector 514 to transfer the processed workpiece Wp from the lower transfer arm 562 to the FOUP 511. Steps 1-4 are then repeated for an unprocessed workpiece W’ to load into the second position of the workpiece holder 125.

[0099] 6. Load the second workpiece holder 125’: the PRO 550 is rotated 180° so that the second slot 544’ of the PRO 550 can be unloaded by the upper transfer arm 561 and the lower transfer arm 562. Steps 1-5 are repeated to unload the processed workpieces Wp” and Wp”’ and load the unprocessed workpieces W” and W”’.

[0100] 7. Transport workpiece holders 125 and 125' for pre-treatment: PRO 550 is pivoted to its second horizontal configuration and conveyor 571 is operated to pick up and transport first workpiece holder 125 (including the unprocessed workpieces W and W' thereon) to pre-treatment module 501. Then, conveyor 571 transports second workpiece holder 125' to pre-treatment module 502.

[0101] 8. Transport workpiece holders 125 and 125' for ECD processing: Conveyor 571 transports pre-processed workpieces W and W' to ECD module 503. Then, workpiece holder 125 is inserted into ECD processing module 503 using drop block 578. Then, conveyor 571 transports pre-processed workpieces W" and W"' to ECD processing module 504.

[0102] 9. Adjust the gap between CPS 200 and workpiece W: Using actuator 325, the gap between CPS 200 and workpiece W inside workpiece holder 125 in ECD module 503 can be set to a value that optimizes the uniformity of the features on workpiece W while keeping CPS 200 and workpiece W parallel. The optimal distance can be determined by modeling the focal length of CPS 200 by computer or by experimental methods. The optimal distance can also depend on the thickness of workpiece W and the degree of curvature of workpiece W, as measured in step 4 above. The gaps for workpieces W', W" and W"' can be similarly set.

[0103] 10. Deposit metal on workpieces: Metal is filled on features of workpieces W, W', W" and W"' using electrochemical deposition.

[0104]

[0105] 11. Complete post-treatment: Workpiece holders 125 and 125' are transported to post-treatment module 505 for rinsing and drying operations.

[0106] 12. Unload processed workpieces: PRO 550 is pivoted to the vertical direction. Workpiece holders 125 and 125' are transported to loader / unloader section 530 and inserted into slots 554 and 554'. PRO 550 is pivoted to the horizontal direction so that processed workpieces W, W', W" and W"' are unloaded as described in workpiece step 3.​

Claims

1. An electrochemical deposition system for depositing metallic features onto a workpiece at various target locations, comprising: Deposition chamber, which is suitable for receiving electroplating solution during use; A workpiece holder for holding a workpiece in a first plane, the workpiece holder being adapted to be inserted into and removed from the deposition chamber while holding the workpiece; A shielding element comprising a substantially flat plate in which an aperture pattern is formed, the aperture pattern substantially corresponding to the target location in use; A shield holder for holding the shield in a second plane substantially parallel to the first plane, the shield holder being adapted to insert into and remove from the deposition chamber while holding the shield; as well as A positioning mechanism for adjusting the position of the workpiece in the first plane, wherein the positioning mechanism is operable to position the workpiece so that the target position is substantially aligned with the aperture pattern when the workpiece holder and the shield holder are inserted into the deposition chamber.

2. The system according to claim 1, wherein, The electrochemical deposition system also includes an actuator operable to change the relative distance between the workpiece holder and the shield holder.

3. The system according to claim 2, wherein, When the workpiece holder and the shield holder are located in the deposition chamber, the actuator can be operated to change their relative distance in a direction perpendicular to the first plane and the second plane.

4. The system according to claim 2, wherein, The positioning mechanism includes an optical camera capable of imaging the features of the workpiece.

5. The system according to claim 2, wherein, The positioning mechanism includes at least one actuator operable to change the relative position of the workpiece and the workpiece holder in a plane parallel to the workpiece.

6. The system according to claim 2, wherein, The positioning mechanism includes a distance sensor capable of measuring the curvature of the workpiece.

7. The system according to claim 1, wherein, The positioning mechanism includes a conveyor arm, which is positioned to receive the workpiece and supply the workpiece to the workpiece holder.

8. The system of claim 1, further comprising a control system, wherein the positioning mechanism is configured to adjust the position of the workpiece in the first plane under the control of the control system.

9. The system according to claim 8, wherein, The positioning system includes at least one actuator configured to move the workpiece within the first plane based on a computer model or data stored in a database.

10. A method for electrochemically depositing metallic features onto a workpiece at various target locations, comprising the steps of: i) Provide a deposition chamber adapted to receive electroplating solution in use; A workpiece holder is provided for holding a workpiece in a first plane, the workpiece holder being adapted to be inserted into and removed from the deposition chamber; as well as A shielding element is provided, the shielding element comprising a substantially flat plate in which an aperture pattern is formed, the aperture pattern substantially corresponding to the target location in use; ii) Insert the shielding member into the deposition chamber; iii) Position the workpiece relative to the workpiece holder within the first plane; iv) Load the positioned workpiece into the workpiece holder; v) Insert the loaded workpiece holder into the deposition chamber; as well as vi) Deposit metallic features onto the workpiece; In step iii), the workpiece is positioned relative to the workpiece holder in the first plane such that when the workpiece holder and the shield are inserted into the deposition chamber, the target position is substantially aligned with the aperture pattern.

11. The method according to claim 10, wherein, Step i) includes providing at least one additional shield.

12. The method according to claim 11, wherein, The shielding element and the at least one additional shielding element are disposed in the shielding element storage area.

13. The method according to claim 12, wherein, Step ii) initially involves selecting a shield from the shield storage area for insertion into the deposition chamber.

14. The method according to claim 13, wherein, In step ii), the shielding element is transported from the shielding element storage area to the deposition chamber.

15. The method according to claim 10, wherein, Step ii) includes inserting the shielding member into a shielding member holder, the shielding member holder holding the shielding member in a second plane substantially parallel to the first plane.

16. The method according to claim 15, wherein, Step ii) further includes inserting the shield into the deposition chamber while holding the shield in place by the shield holder.

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