Clean workpiece loader and edge protection holder for wet chemical semiconductor processing

Abstract

To provide a workpiece holder that improves plating uniformity while overcoming the limitations of conventional workpiece frame holders for wet chemical processing including electric plating, protects fragile rectangular workpieces on all four edges, and enables a shield to be arranged within several mm on both faces of the workpiece.SOLUTION: An apparatus for loading and transport of fragile flexible workpieces for use in wet chemical semiconductor processing is described. A loader aligns a workpiece in a frame while maintaining minimal physical contact. A holder precisely positions at least two edges of the workpiece, while providing workpiece edge protection and straightening on the remaining two edges. The holder allows fluid processing of both faces of the workpiece while allowing a shield or agitation plate to be positioned close to the faces of the workpiece.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to methods and systems for wet chemical semiconductor processing, such as cleaning, etching, and electroplating of semiconductor substrates for advanced packaging or high density interconnect applications. More particularly, the present invention relates to systems and methods for cleaning, handling, transporting, and protecting thin and fragile substrates for use in wet chemical processes, including electrochemical deposition. [Background technology]

[0002] Electrochemical deposition is used as a manufacturing technique for the application of thin films to semiconductor substrates, including semiconductor wafers and rectangular panels. The films can include copper, tin, nickel, cobalt-iron, indium, and other metals. During electrochemical deposition, an electric current flows from an anode through a plating bath to a cathode. When a substrate is used as the cathode, a metal can be deposited onto it.

[0003] Advanced packaging involves the interconnection of components before applying traditional integrated circuit packaging processes. Advanced packaging allows multiple devices to be integrated and packaged as a single electronic device. Rectangular substrate panels are one type of advanced packaging substrate, which allows large, complex systems to be built on the panel substrate, realizing manufacturing and cost advantages. Rectangular substrate panels are typically fabricated as organic laminates consisting of glass fiber reinforcement in an epoxy composite matrix, a composition similar to that of printed circuit boards.

[0004] High-purity glass has important advantages over organic laminates as the base material for rectangular panel substrates. Advantages include dimensional stability and a thermal expansion coefficient similar to silicon, both of which are important in heterogeneous integration applications. Direct die-to-glass bonding improves thermal properties compared to organic laminates. Pure glass as a panel substrate also allows for the filling of through-glass vias using electroplating.

[0005] While glass offers processing advantages when used as a substrate, it is also a brittle ceramic that can break if not handled properly. Cracks in glass-containing ceramics typically propagate from edge defects caused by surface contact or localized stress. Cracking and breakage can also occur if the edge is bent beyond a threshold angle that depends on the thickness. Glass substrates for panels can be very thin, with a typical starting thickness of 200–400 μm before buildup. When held horizontally by their edges, thin glass substrates exhibit significant sagging due to gravity. When held vertically, thin glass substrates can sag due to unbalanced intrinsic stresses in the deposited layers.

[0006] Workpiece holders are used to transport substrates through wet processing tools. When used in electroplating tools, the workpiece holder also provides electrical contact during electroplating. Electrical contact with the workpiece or substrate typically occurs on the surface in the edge region where the holder's metal contacts physically contact the metal seed layer on the workpiece surface. This contact area must be kept dry to avoid metal buildup on the contacts and seed deplating due to localized galvanic cells. Therefore, an important function of the holder is to seal the contact area to prevent the electroplating solution from wetting the electrical contacts and seed layer.

[0007] Workpiece holders for wet processing steps such as chemical etching, photoresist stripping, and cleaning must provide reliable support of the substrate, typically in a vertical orientation, in a wet chemical process module with minimal physical contact with the workpiece so that the chemical removal process is not blocked by the workpiece holder surface that secures the substrate.

[0008] After processing, the workpiece holder is removed from the processing bath and transferred to the next processing step. Some processing fluid is transferred along with the frame and workpiece; this fluid is known as "dragout." Minimizing dragout is an important design goal for workpiece holders.

[0009] Thin, flexible glass workpieces require careful handling when loading and unloading them into holders to maintain cleanliness during insertion into the holder. To prevent the introduction of particle contamination, physical contact with the workpiece is limited to narrow zones outside the device area on the workpiece. These allowable contact areas are called "keep-out zones" (KOZ). During all processing steps, from the removal of the workpiece from its factory transport carrier, commonly called a FOUP (Front Opening Unified Pod), processing equipment should only contact the workpiece in the KOZ.

[0010] Holders for wet semiconductor processing of rectangular workpieces can contact and / or restrain two, three, or four edges of the workpiece, and for vertical processing typically contact both the front and back of the workpiece. Prior art holders have various limitations that are addressed by the present invention.

[0011] A known electroplating system, in which a workpiece holder is used that contacts and restrains only two ends, namely opposing ends, will be described with reference to Figures 1 to 4.

[0012] 1 schematically illustrates a known electroplating tool 50, as described in U.S. Patent No. 11,887,874, incorporated herein by reference. The electroplating tool 50 includes an input / output module 51, a loader / unloader module 52, a workpiece holder storage module 53, process modules 54-58, a proximity patterning shield storage module 59, a transfer support area 65, a maintenance support area 66, an electrochemical system area 67, and a workpiece holder cleaning module 68. The tool 50 is a single-ended tool, in which unprocessed workpieces are introduced into the tool and processed workpieces are removed from the tool in the same input / output front-end module 51. The input / output front-end module 51 includes one or more front-opening unified pods (FOUPs) 69 and an equipment front-end module (EFEM) robot 70 that transfers workpieces between the input / output module 51 and the loader / unloader module 52.

[0013] Although FIG. 1 shows five process modules, tool 50 can have any number of process modules depending on the exact processes being performed, such as the number of different metals being electroplated, the number of pre- and post-plating processes, and the number of overlapping modules used in parallel to increase the throughput of the tool.

[0014] The workpiece holder storage module 53 is used to store the workpiece holders 100 when they are not in use. A local transport (not shown) transfers the workpiece holders 100 from the storage area 53 to the loader / unloader 52 to place them in service. The transport support area 65 provides mechanical, electrical, and fluid support for the loader / unloader 52, the process modules 54-58, and two or more transports that protrude into the CPS storage area 59. The electrochemical systems area 67 houses the power distribution and fluid handling systems for all other modules. The maintenance support area 66 allows support personnel access to the equipment in the electrochemical systems area 67 and all electrical and fluid connections in the process modules 54-58. The workpiece holder cleaning module 68 includes equipment for cleaning the workpiece holders 100 when they are not being used to process workpieces.

[0015] The process flow for an unprocessed workpiece within tool 50 begins with the transfer of the workpiece by EFEM robot 70 from input / output module 51 to loader / unloader module 52, where workpiece 60 (not shown) is loaded into a workpiece holder. The loaded workpiece holder is then transported using a transfer mechanism to a series of pre-processing modules 54-55 for wet processing steps such as pre-cleaning, pre-rinsing, and chemical activation. The loaded workpiece holder 100 is then transported to either process module 56 or 57 for electroplating. After electroplating, the loaded workpiece holder 100 is transported to process module 58 for further processing steps such as a final rinse and drying. Following the final rinse and drying, the loaded workpiece holder 100 is transported to loader / unloader module 52, where the workpiece W is ejected from workpiece holder 100. The processed workpieces W are then transferred to the input / output module 51 for storage until all workpieces in the current batch have been processed.

[0016] FIG. 2 illustrates a double-sided workpiece holder 100 used during electroplating, for example, to transport workpieces between process modules in an electroplating tool 50. The workpiece holder 100 is described in detail in U.S. Pat. No. 10,283,396, incorporated herein by reference. The workpiece holder 100 is formed as a frame including a header member 107 configured to be gripped and transported to and from a process cell. Lateral supports 111 and 112 extend from the ends of the header member 107. Contact sealing strips 121 and 122 are attached along the lengths of the lateral supports 111 and 112. During use, inner ends of the flexible contact sealing strips 121 and 122 contact opposite sides of the workpiece to provide a fluid seal and electrical contact at the KOZ region of the workpiece (see below).

[0017] FIG. 3 shows a bottom view of a portion of the workpiece holder 100 and the contact sealing strip 122 with the elongated actuating member 144 inserted. The contact sealing strip 122 includes electrical contacts 125 and 126 disposed at the ends of the respective bending grips 123, 124. The bending grips 123, 124 are in the form of a thin, flexible sheet having a resiliently deformable conductive center and integrally formed electrical contacts 125, 126, each surrounded and sealed by a corresponding insulator 131, 132. The bending grips 123, 124 are biased into a closed configuration (as shown in FIG. 4 below), in which they are relatively close together. The actuating member 144 includes a bladder 146 that can be inflated using atmospheric pressure control (not shown) to extend and separate a pair of arms 147, one on each side of the bladder 146. The arms 147 are biased into a closed configuration (as shown in FIG. 4 below) in which they are relatively close together. Each arm 147 engages an inner surface of a respective one of the bending grips 123, 124. FIG. 3 shows the bladder 146 in an inflated configuration, and the arms 147, and therefore the bending grips 123, 124, are accordingly forced apart to allow the workpiece 60 to be inserted.

[0018] FIG. 4 shows a view of the workpiece holder 100 and contact sealing strip 122 in a configuration similar to that of FIG. 3 with the bladder 146 uninflated. When the bladder 146 is uninflated, the flexure grips 123, 124 provide a gripping force on the workpiece 60 such that the faces of the workpiece 60 are in electrical contact with the electrical contacts 125 and 126, respectively. In this configuration, the corresponding insulators 131 and 132 provide a fluid seal, preventing fluid from wetting the contacts 125 and 126. A proximity patterning shield 70 having an aperture opening 71 is also shown in FIG. 4. When positioned at the correct focal distance relative to the workpiece 60, the proximity patterning shield 70 improves the uniformity of features electroplated and patterned on the workpiece 60.

[0019] Details of the workpiece holder 100 and contact sealing strips 122 and 122 are described in U.S. Patent No. 10,283,396, assigned to the present applicant and incorporated in its entirety. Details of the proximity patterning shield 70 and its use are described in U.S. Patent No. 11,608,563, assigned to the present applicant, and U.S. Patent Application No. US20220148891A1, both of which are incorporated in their entirety.

[0020] In other wet processing applications, the contact sealing strip may be replaced by a similar flexible structure that contacts only the substrate surface in the KOZ area without conducting current; for example, the flexure grip may be made entirely from a plastic such as PEEK.

[0021] It has been argued that holders that clamp only two edges of a rectangular substrate, such as the workpiece holder 100 described above, as well as alternatives (not shown) that clamp three edges, pose a risk of substrate damage if the unprotected workpiece edge comes into contact with a processing module surface, as such contact is more likely with thin, curved workpieces. Accordingly, four-sided frame holders have been developed that protect the workpiece edge against such contact, but such holders have been found to have deficiencies that negate any observed improvements, as discussed below.

[0022] Known four-sided frame holders are typically constructed with a front frame that presses the workpiece edge against a backing plate or rear frame. A mechanical or magnetic lock, or a vacuum mechanism, can be activated to clamp the front and rear of the frame. Such a configuration can allow plating on only one side of the workpiece. Furthermore, the activated mechanical, magnetic, or vacuum locking mechanisms of known four-sided frames sometimes utilize O-rings as fluid seals. Over time, such seals typically leak, resulting in chemical fluid infiltration that contaminates electrical contacts and locking mechanisms with plating bath chemicals and damages components with acidic chemicals, requiring extensive cleanup.

[0023] Additionally, the front frame of such four-sided frame holders is too thick to allow for placement of either an electric field uniformity shield or a fluid stir plate close enough to the workpiece. Proximity positioning shields containing a pattern of apertures corresponding to target locations on the workpiece, as described in U.S. Pat. No. 11,608,563, are used in electroplating to improve the uniformity of features plated on the workpiece. Stir plates are used to increase the rate of plating, stripping, or etching by uniformly increasing the delivery of process chemical constituents to the workpiece surface. Both the proximity positioning shield and the stir plate must be positioned within a few millimeters of the workpiece, which was not possible using known four-sided frame holders. [Prior art documents] [Patent documents]

[0024] [Patent Document 1] U.S. Patent No. 11,887,874 [Patent Document 2] U.S. Patent No. 10,283,396 [Patent Document 3] U.S. Patent No. 11,608,563 [Patent Document 4] U.S. Patent Application No. US20220148891A1 Summary of the Invention [Problem to be solved by the invention]

[0025] It is an object of the present invention to provide a workpiece holder that overcomes the limitations of workpiece frame holders for wet chemical processing, including electroplating, as described above, while improving plating uniformity, protecting fragile rectangular workpieces on all four edges, and allowing shields to be placed within a few millimeters on both sides of the workpiece. The design does not use either locking clamps or O-rings, eliminating the risk of internal frame holder contamination due to fluid leakage. Semiconductor processing equipment for use with such a workpiece holder includes a loader that supports and restrains the workpiece during insertion into the holder and faces the KOZ contact, consistent with high cleanliness requirements. [Means for solving the problem]

[0026] According to a first aspect of the present invention, there is provided a workpiece holder for holding a substantially flat, rectangular workpiece in a processing chamber of a wet semiconductor processing system, the workpiece holder being adapted for insertion into and removal from the processing chamber while holding the workpiece; Here, the workpiece holder is first and second lateral supports; first and second bending grips disposed on the first and second lateral supports, respectively, the bending grips being movable between a closed configuration in which the bending grips contact and restrain respective first and second opposite ends of a workpiece during use, and an open configuration in which the bending grips are sufficiently open to allow a workpiece to be inserted into the bending grips in a direction generally parallel to the first and second lateral supports during a loading operation; an end protector extending in use between the first lateral support and the second lateral support; Equipped with.

[0027] According to a second aspect of the present invention there is provided a semiconductor processing system for processing a substantially flat rectangular workpiece whilst loaded into a workpiece holder of the first aspect, the system comprising: a processing chamber for wet chemical etching, cleaning or electrodeposition; a loader for loading a workpiece into the workpiece holder during a loading operation; Equipped with.

[0028] Other specific aspects and features of the present invention are set out in the accompanying claims.

[0029] The present invention will now be described with reference to the accompanying drawings (not to scale): [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic diagram of a known electrochemical deposition system; [Figure 2] 1 is a schematic perspective view of a known double-sided workpiece holder; FIG. [Figure 3] 3 is a schematic cross-sectional view of the workpiece holder of FIG. 2 having an elongated actuating member. [Figure 4] 3 is a schematic cross-sectional view of the workpiece holder and proximity positioning shield of FIG. 2. [Figure 5] FIG. 1 is a schematic side view showing a workpiece holder having an upper end protective guide. [Figure 6] 10 is a schematic side view illustrating a workpiece frame having upper and lower end protection guides in accordance with an alternative embodiment of the present invention. [Figure 7A] FIG. 10 is a schematic side view showing details of the end protection guide. [Figure 7B] FIG. 10 is a schematic top view showing details of the end protection guide. [Figure 7C] FIG. 4 is a schematic cross-sectional view showing details of an end protection guide. [Figure 8] FIG. 2 is a schematic rear view showing the workpiece plating and processing areas of an exemplary workpiece. [Figure 9] FIG. 2 is a schematic top view showing a workpiece transfer arm. [Figure 10] FIG. 2 is a schematic isometric view of the workpiece alignment and loader module in a configuration with a workpiece inserted into a workpiece holder. [Figure 11] 11 is a schematic isometric view showing the workpiece alignment and loader module of FIG. 10 in a configuration for transporting a workpiece holder. [Figure 12] FIG. 2 is a schematic isometric view of a workpiece holder. [Figure 13] FIG. 10 is a side view showing the edge protection guide holder and interlock assist. [Figure 14] 1 is a schematic isometric view of a portion of a workpiece holder having an edge protection guide holder, an interlocking aid, and an edge protection guide prior to inserting a workpiece into the workpiece holder. FIG. [Figure 15] 1 is a schematic isometric view of a portion of a workpiece holder having an edge protection guide holder, an interlocking aid, and an edge protection guide after a workpiece has been inserted into the workpiece holder. FIG. [Figure 16A] FIG. 1 illustrates a deposition profile for a known four-sided workpiece holder. [Figure 16B] FIG. 10 illustrates a deposition profile for a workpiece holder with an edge protection guide of the present application. [Figure 16C] FIG. 10 illustrates a deposition profile for a workpiece holder with an edge protection guide of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0031] For consistency and clarity, like reference numerals will be retained for like components throughout the following description. Figures 2-8 are illustrated with reference orthogonal axes A, B, and C fixed relative to the workpiece (or the workpiece holder when the workpiece is held in a workpiece holder), and these are used consistently throughout these figures to aid in understanding the figures.

[0032] FIG. 5 shares some similarity with the one shown in FIG. 2 and shows a workpiece holder 200 including a header member 107 carrying lateral supports 111 and 112 at opposite ends thereof, and respective contact sealing strips 121 and 122 carried by each lateral support 111 and 112. However, workpiece holder 200 includes an upper edge protection guide (EPG) 175 attached to lateral supports 111 and 112 via supports 186 by clamps 185. A workpiece 60 is shown held by workpiece holder 200, but the workpiece 60 is deflected as shown. The upper edge of the workpiece 60 is held straight and restrained by guide projections 190 and 190′ (see FIG. 7A ) on the upper EPG 175. This structure is described in more detail below. The lower edge of the deflected workpiece 60 is unrestrained. The flexing grips 131 and 132 are attached to the lateral supports 111 and 112 via fasteners 130 and are flexed open by inflated bladders 146 (not shown). For wet processes requiring electrical contact with the workpiece 60, such as electroplating, contact sealing strips 121 and 122 can be used for the flexing grips 131 and 132. For wet processes not requiring electrical contact, such as etching or cleaning, the flexing grips 131 and 132 can be equipped with spring members overmolded with a corresponding insulating material or fabricated from a rigid plastic material such as PEEK. The flexing grips 131 and 132 can be fabricated from a stainless steel alloy overmolded with an elastomer, such as a fluoroelastomer or perfluoroelastomer, selected for its high bending strength and resistance to deflection. An elastomer thickness of approximately 0.5 to 3 mm may be required to achieve sufficient durability.

[0033] In a preferred embodiment, the lateral supports 111, 112, bending grips 131, 132 and actuation mechanisms therefor may be substantially identical to those previously described with reference to Figures 4 and 5 and have the same cross-sections as shown in those figures, and the present invention will hereinafter assume this is the case and, for consistency, will be described using like reference numerals where appropriate. In this case, the opening and closing of clamp 185 is affected by the expansion and contraction of bladder 146 in a manner similar to the opening and closing of bending grips 131, 132, respectively.

[0034] The sides of workpiece 60 are again unconstrained here because contact sealing strips 121 and 122 are bent open by inflated bladder 146, similar to the arrangement shown in FIG.

[0035] The upper EPG 175 can be conveniently assembled with the workpiece holder 200 so that the upper EPG 175 is permanently or semi-permanently secured thereto.

[0036] 6 shows an alternative four-sided workpiece holder 200′ generally similar to the workpiece holder 200 shown in FIG. 5 , having an upper EPG 175 attached to the lateral supports 111 and 112 via supports 186 by clamps 185, and contact sealing strips 121, 122 carried by the respective lateral supports 111, 112, but modified in that it also includes a lower EPG 176 attached to the lateral supports 111 and 112 by clamps 181. Opening and closing of the clamp 181 is affected by the expansion and contraction of the bladder 146 in a manner similar to the opening and closing of the flexure grips 131, 132, respectively. Both the upper and lower ends of the workpiece 60 are held straight and restrained by guide features 190, 190′ of the upper and lower EPGs 175, 176. 6, after bladder 146 (not shown) has shrunk, contact sealing strips 121 and 122 and flexure grips 131 and 132 act to clamp the ends of workpiece 60. Upper and lower EPGs 175 and 176 may be fabricated, for example, from a polymer such as polyetheretherketone or high density polyethylene, or from stainless steel coated with a polymer such as ECTFE (trademark Halar), PTFE, or an elastomer such as Viton.

[0037] FIG. 7A shows a portion of an EPG, in this case the lower EPG 176, as viewed from the side. It should be understood that the upper EPG 175 has a similar structure. The EPG 176 includes a base 195 supporting repeating pairs of guide projections 190 and 190' projecting upward therefrom. The guide projections 190 and 190' have a width W and a cross-sectional spacing S between each pair of guide features in a horizontal direction parallel to the plane of the workpiece 60. The incorporation of spacing S can help minimize fluid dragout after wet chemical processing, including etching, cleaning, or electrodeposition. Adjacent pairs of guide projections 190 and 190' are spaced apart in the same direction by a gap G1. For a typical workpiece 60 having linear dimensions of 300-1000 mm, the width W may be approximately 5-15 mm, the cross-sectional spacing S may be approximately 1-5 mm, and the spacing G1 may be approximately 30-100 mm.

[0038] 7B shows a portion of the lower EPG 176 as viewed from above. The guide projections 190 and 190' are spaced apart a distance G2 in a direction perpendicular to the plane of the workpiece 60, selected to be sufficient to restrain the workpiece 60 for insertion into the processing cell while providing sufficient spacing to allow access for high-velocity air directed at the panel edge during the final drying operation. Depending on the thickness of the workpiece 60, the spacing G2 may be approximately 0.5 to 2.5 mm. The illustrated guide projections 190, 190' are chamfered at their upper ends and are beveled at the inner recessed end 197 and outer end 196.

[0039] 7C shows a detail of guide projections 190 and 190' in cross section in the plane of workpiece 60 perpendicular to the plane of the paper, where it can be seen that lead-in end 197 is sufficiently angled to guide and capture the workpiece end (not shown) during loading.

[0040] As noted above, while the upper EPG 175 can be attached to the workpiece holder 200, 200′ during assembly, it will be appreciated that the lower EPG 176 cannot be so attached (i.e., to convert the workpiece holder 200 to the workpiece holder 200′) because the lower EPG 176 would interfere with loading a workpiece into the workpiece holder 200′. Instead, attachment of the lower EPG 176 must occur after the workpiece has been loaded, and the mechanism for accomplishing this is described later below.

[0041] FIG. 8 shows a workpiece 60 having device areas 204 arranged in quadrants 201, separated by cross areas 203 where no devices are present. Additional device-free areas 202 surround quadrant 201 at the edge of workpiece 60. Area 204 may contain patterned photoresist with openings through glass vias or other features prior to electroplating. The positioning of active areas on the workpiece is constrained by design rules, which divide the panel area into areas where plating is permitted and so-called keep-out zones (KOZs) where plating is not permitted, including areas 202 and 203, as shown. Keep-out zones may include exclusion areas near the edges of the workpiece. Workpiece 60 is allowed to physically contact only within narrow KOZ areas 203 and 202 to prevent particle contamination associated with physical contact.

[0042] FIG. 9 shows a workpiece transfer arm 230, also known as an end effector, for supporting a workpiece 60 thereon during insertion of the workpiece 60 into the workpiece holder 200 or 200′ using a loader, as described in more detail below. The workpiece transfer arm 230 includes a vertical-horizontal plate support 231, three end effector structural beams 232, each carrying a raised contact support 233, an actuator 235 with a bladder 237, and a clamp finger contact 236. Gripping or releasing the workpiece 60 can be achieved by inflating or deflating the bladder 237. Alternatively, a vacuum suction cup may be used to grip or release the workpiece 60. The end effector structural beam 232 may be fabricated, for example, from carbon fiber or other lightweight, rigid material. The clamp finger contact 236 is configured to clamp and unclamp the end of the workpiece 60 to flatten the raised end when actuated by the actuator 235. The width and spacing of the clamp finger contacts 236 are selected to interleave with the EPG guide protrusions 190 during use. Raised contact supports 233 projecting outward from each structural beam 232 contact the workpiece 60 only at the KOZ regions 202 and 203. Figures 9-11 are illustrated with orthogonal axes X, Y, and Z, where X and Y extend in a horizontal plane and Z extends vertically.

[0043] 10 shows the workpiece registration and loader module 250 in a horizontal configuration, used to insert or remove workpieces 60 from the workpiece holders 200, 200′. The registration and loader module 250 includes a registration assembly 260 and a tilt loader assembly 270.

[0044] The alignment assembly 260 includes a YZ stage 252 (movable along the Y and Z axes shown), a transfer arm 230, and support rails 253 and 254, with rail 253 extending parallel to the Y axis to allow movement of the YZ stage 252 along the Y axis, and rail 254 extending parallel to the Z axis to allow movement of the YZ stage 252 along the Z axis. The tilt loader assembly 270 includes a tilt arm 251 and a workpiece loader 300. The YZ stage 252 can position the transfer arm 230 in two dimensions, i.e., parallel to the Y and / or Z axes, using rails 253 and 254. The range of movement parallel to the Y axis is sufficient to move the transfer arm 230 and any workpiece 60 supported thereon into the tilt loader assembly 270. The rails 253 and 254 can be formed, for example, from extruded aluminum or other lightweight metal alloys. The tilt arm 251 is pivotable by a motor (not shown) about an axis parallel to the X-axis through a rotation range of approximately 90 degrees from a horizontal configuration shown in Figure 10 to a vertical configuration shown in Figure 11. Also shown in Figure 10 is the horizontal plate support 231 that mounts the transfer arm 230 to the YZ stage 252, and the clamp finger contact 236 that, when affected by the expansion of the bladder 237, flattens the end of the workpiece closest to the tilt arm 251 during insertion into the workpiece holder 200, 200'. The alignment assembly 260 is capable of aligning the workpiece 60 on the transfer arm 230 using a stepper motor (not shown) that contacts the end of the workpiece 60.

[0045] 11 shows workpiece alignment and loader module 250, in which tilt arm 251 is oriented in a vertical configuration that allows workpiece holder 200 to be inserted and removed from workpiece loader 300 by an overhead transport (not shown). Workpiece holder 200 is inserted into one of two parallel slots (302, see FIG. 12) in the top surface shown of workpiece loader 300. Tilt arm 251 and workpiece loader 300 may be fabricated, for example, from aluminum or other lightweight metal alloy.

[0046] FIG. 12 shows workpiece loader 300 separated from the rest of alignment assembly 260 prior to inserting workpiece holder 200 into one of receiving slots 302. In this view, workpiece loader 300 is shown rotated 180 degrees from the orientation shown in FIG. 10. Workpiece loader 300 includes support frame 301, workpiece holder guides 303, edge protection guide holders 310, and interlock assist 320. These items are described in more detail with reference to FIGS. 13-15 below.

[0047] FIG. 13 shows an edge protection guide holder 310 and an interlock assist 320. These items are used in attaching the lower EPG 176 to the workpiece holder 200′ following workpiece loading. The edge protection guide holder 310 includes an upper support 311, a lower support 312, an upper clamp 315, and a lower clamp 316. The interlock assist 321 includes an upper support 321, a lower support 322, an upper finger 325, and a lower finger 326. Also shown in FIG. 13 is the lower EPG 176, as previously described, with its guide projection 190, and the workpiece 60. The edge protection guide holder 310 can be actuated to grip or release the lower EPG 176 using pneumatic or mechanical action (not shown).

[0048] Figure 14 shows the edge protector guide holder 310, interlock assist 320, lower EPG 176, and workpiece 60 in a position prior to inserting the workpiece 60 into the lower EPG 176. Also shown in Figure 14 are the contact sealing strip 122, electrical contacts 125, lateral supports 112, clamp 181, and inflatable bladder 146. The contact sealing strip 122 and clamp 181 are shown in an open position consistent with the inflation of bladder 146. The edge protector holder upper support 311 and lower support 312 are shown in a closed position, gripping the lower EPG 176.

[0049] 15 shows the edge protection guide holder 310, interlock assist 320, lower EPG 176, and workpiece 60 after inserting the workpiece 60 into the lower EPG 176 by moving the workpiece transfer arm 230 parallel to the Y-axis using rails 253. The contact sealing strip 122 and clamp 181 are shown in the closed position, aligned with the uninflated bladder 146. The lower EPG 176 is shown clamped onto the lateral support 112, with the electrical contacts 125 in contact with the workpiece 60. The edge protection upper clamp 311 and lower clamp 312 are shown in the open position after the lower EPG 176 has been released. The interlock assist upper and lower fingers 325 and 326 are in the closed position, straightening the holding edge of the workpiece 60.

[0050] An exemplary method for loading and processing a workpiece 60 using the workpiece holder 200' in an electrochemical deposition system includes the following steps. 1. Provide the lower EPG 176 to the EPG guide holder 310 either manually or by removing it from the workpiece holder 200' that does not contain the workpiece 60. 2. Use the tilt arm 251 to rotate the loader assembly 270 to a vertical orientation (as shown in FIG. 11). 3. Using the overhead transport, load the empty workpiece holder 200' containing the upper and lower EPGs 175, 176 attached into one of the slots 302 of the workpiece loader 300. 4. Use the tilt arm 251 to rotate the loader assembly 270 to its horizontal orientation (as shown in Figure 10). 5. Remove the unprocessed workpiece 60 from the FOUP 69 using the EFEM robot 70. 6. Move the YZ stage 231 to the transfer position height. 7. Place the workpiece 60 on the end effector 230 using the EFEM robot 70. 8. Clamp the workpiece 60 on the end effector 230 using the clamp finger contacts 236. 9. Open the edge protection guide holder 310 and interlock aid 320. 10. Clamp the lower EPG 176 with the EPG holder 310. 11. Inflate bag 146. 12. Remove the lower EPG 176 from the workpiece holder 200. 13. Insert workpiece 60 into interlock assist 320 using transfer arm 230. 14. Clamp and straighten the end of the workpiece 60 with the interlocking aid 320. 15. Insert the clamped and straightened workpiece 60 into the lower EPG 176 by moving the transfer arm 230. 16. Deflate the bladder 146, thereby securing the workpiece 60 within the workpiece holder 200'. 17 Unclamp the EPG holder 310. 18. Separate the transfer arm 230 from the workpiece 60. 19. Move transfer arm 230 from loader assembly 270. 20. Use tilt arm 251 to rotate loader assembly 270 to its vertical orientation. 21. Transport the loaded workpiece holder 200 to the pre-process module 54 using the overhead transport.

[0051] 16A-16C show deposition profiles for a workpiece holder with four-sided electrical contacts (FIG. 16A), a workpiece holder 200′ with upper and lower EPGs 175 and 176 (FIG. 16B), and a workpiece holder 200 with upper and lower EPGs 175 and 176 and a shield (FIG. 16C). The profiles show copper deposition thickness in microns for a plating cell geometry of a P500 ECD Panel Tool available from ASMPT NEXX, Billerica, Massachusetts, calculated using the Electrodeposition module in COMSOL Multiphysics, available from COMSOL Inc., Burlington, Massachusetts. Simulation parameters include an initial copper seed thickness of approximately 100 nm for a workpiece measuring approximately 510 x 515 mm, a plating rate of approximately 3.6 amperes per square decimeter, and a target deposition thickness of 12 microns. Each graph shows the deposition thickness along a diagonal cross section, with the position in millimeters being the distance from the center of the workpiece to the corner. The curves on each graph show the thickness after 300 seconds and 900 seconds.

[0052] One source of non-uniformity in Figures 16A-16C is thermal effects, which result in increased plating near the edges due to a drop in electrical potential in the seed layer and plating film across the workpiece. A second source of non-uniformity is seen at the corners of rectangular workpieces. This non-uniformity exists whether electrical contact is made near a corner along one or both edges of the workpiece. This is an unexpected finding related to the electric field distribution on the face of the workpiece when current flows near a corner. This result is different from round workpieces, where optimal uniformity is achieved by surrounding the workpiece with electrical contacts.

[0053] Table 1 lists the standard deviations of the deposition profiles in Figures 16A-16C. The basic uniformity of the four-sided workpiece holder and the workpiece holder 200 with EPG 176 is similar. To further improve plating uniformity, an additional shield, such as proximity shield 71, can be used. The thin profile of EPG 175 allows for the shield 71 to be placed as close as about 2-10 mm from the workpiece, a configuration not possible using prior art four-sided workpiece holders.

[0054] [Table 1]

[0055] Table 1 shows the standard deviation of deposition uniformity along the diagonal from the center to the corner of the workpiece as a function of time for each curve shown in Figures 16A-16C.

[0056] The results shown in Figures 16A-16C and Table 1 suggest that plating systems incorporating workpiece holders that protect the four edges of the workpiece while providing electrical contact along two edges have advantages over holders that provide contact along all four edges. [Explanation of symbols]

[0057] 50 Electroplating Tools 51 Input / output module, input / output front-end module 52 Loader / Unloader Module 53 Workpiece holder storage module, storage area 54 Process module, preprocessing 55 Process module, preprocessing 56 Process Module, ECD 57 Process Module, ECD 58 Process Module, Post-Process 59 Proximity Patterning Shield Containment Module, CPS Containment Area 60 workpieces 65 Conveyor Support Area 66 Maintenance Support Area 67 Electrochemical Systems Section 68 Workpiece Holder Cleaning Module 69 Front-opening Unified Pod, FOUP 70 Equipment front-end module robot, EFEM robot, proximity patterning shield 71 Aperture opening, proximity shield 100 Workpiece Holder 107 Header member 111 Lateral Support 112 Lateral Support 121 Contact sealing strip 122 Contact sealing strip 123 Flexed Grip 124 Flexed Grip 125 Electrical Contacts 126 Electrical Contacts 130 Fasteners 131 Insulator, bending grip 132 Insulator, bending grip 144 Actuating member 146 bags 147 Arms 175 Upper end protection guide, upper EPG 176 Lower EPG 181 Clamp 185 Clamp 186 Support 190 Guide protrusions, guide features 190' guide protrusion, guide feature 195 Base 196 Outer edge 197 Retracted end 200 Workpiece Holder 200' 4-sided workpiece holder 201 quadrant 202 area 203 Cross area, KOZ area 204 Device Area 230 Workpiece transfer arm, end effector 231 Vertical horizontal plate support 232 End Effector Structure Beam 233 Raised contact support 235 Actuator 236 Clamp finger contact 237 bags 250 Workpiece Alignment and Loader Module 251 Inclined Arm 252 YZ Stage 253 Support Rail 254 Support Rail 260 Alignment Assembly 270 Tilting loader assembly 300 Workpiece Loader 301 Support Frame 302 Slots 303 Workpiece holder guide 310 Edge protection guide holder, EPG guide holder 311 Upper support 312 Lower support 315 Upper clamp 316 Lower Clamp 320 Interlock Aid 321 Interlocking aid, upper support 322 Lower support 325 Upper Finger 326 Lower Finger

Claims

1. 1. A workpiece holder for holding a substantially flat, rectangular workpiece in a process chamber of a wet semiconductor processing system, the workpiece holder being adapted for insertion into and removal from the process chamber while holding the workpiece; a first lateral support and a second lateral support; first and second bending grips disposed on the first and second lateral supports, respectively, the bending grips being movable between a closed configuration in which the bending grips contact and restrain first and second opposing ends of the workpiece, respectively, during use, and an open configuration in which the bending grips are sufficiently open to allow the workpiece to be inserted into the bending grips in a direction generally parallel to the first and second lateral supports during a loading operation; an end protector extending in use between the first lateral support and the second lateral support; A workpiece holder comprising:

2. 10. The workpiece holder of claim 1, wherein the first bending grip and the second bending grip comprise electrical contacts for applying electrical current to respective first opposing ends and second opposing ends of the workpiece during use.

3. The workpiece holder of claim 1 , wherein the edge protection guide comprises an elongated U-shaped channel for receiving the workpiece during use.

4. 4. The workpiece holder of claim 3, comprising a plurality of guide protrusions positioned along the length of the U-shaped channel on opposite sides of the U-shaped channel for guiding the workpiece into the U-shaped channel during the loading operation.

5. 5. The workpiece holder of claim 4, wherein the guide protrusions positioned on a first side of the U-shaped channel are interleaved with the guide protrusions positioned on an opposing second side of the U-shaped channel along the length of the U-shaped channel.

6. 10. The workpiece holder of claim 1, wherein the end protectors are insulating so that current is not supplied to the workpiece through the end protectors during use.

7. 7. The workpiece holder of claim 6, wherein the end protectors are fabricated from a thermoplastic material selected from the group consisting of high density polyethylene and polyetheretherketone.

8. 7. The workpiece holder of claim 6, wherein the end protectors are fabricated from stainless steel coated with a fluorinated polymer selected from the group consisting of Viton, polytetrafluoroethylene, and ethylene chlorotrifluoroethylene.

9. 2. The workpiece holder of claim 1, further comprising a header member connecting the first lateral support and the second lateral support, the arrangement being such that, in use, the header member and the first lateral support and the second lateral support surround three edges around the workpiece.

10. 10. The workpiece holder of claim 9, wherein the end protector is disposed parallel to and adjacent to the header member.

11. 10. The workpiece holder of claim 9, wherein the end protectors are disposed parallel to and spaced apart from the header member, the arrangement being such that, in use, the header member, the first lateral support and the second lateral support, and the end protectors surround all four ends of the workpiece.

12. 11. The workpiece holder of claim 10, further comprising a second end protector, the second end protector being arranged parallel to and spaced apart from the header member, the arrangement being such that, in use, the first end protector, the first lateral support and the second lateral support, and the second end protector surround all four ends of the workpiece.

13. 10. A semiconductor processing system for processing a substantially flat rectangular workpiece while loaded into the workpiece holder of claim 1, comprising: a processing chamber for wet chemical etching, cleaning or electrodeposition; a workpiece loader for loading the workpiece into the workpiece holder during the loading operation; A system comprising:

14. 14. The semiconductor processing system of claim 13, wherein the loader comprises a contact portion configured to contact the workpiece around a periphery of the workpiece.

15. 14. The semiconductor processing system of claim 13, wherein said loader comprises end clamps for straightening said workpiece during loading into said workpiece holder.

16. 16. The semiconductor processing system of claim 15, wherein when loaded with the workpiece holder of claim 4, said end clamps interleave with said guide projections.

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