Substrate Holder, Plating Apparatus, and Substrate Positioning Method

The present invention relates to a substrate holder, a plating apparatus, and a substrate positioning method.

To form a thin metal film on a surface of a substrate, a plating apparatus is used. In the plating apparatus, a substrate holder that releasably holds a substrate such as a semiconductor wafer may be used. Then, in the plating apparatus, the substrate held by the substrate holder is immersed in a plating solution, and a voltage is applied to the substrate, so that the surface of the substrate is plated.

An example of the substrate holder is described in PTL 1. PTL 1 discloses, as shown inthereof, a substrate holder including a first holding member, and a second holding memberthat sandwiches and holds a substrate Wf with the first holding member. The second holding memberincludes a positioning memberfor positioning the substrate Wf at a predetermined position. The first holding memberincludes a protrusion. Then, when the first holding memberand second holding membersandwich and hold the substrate Wf, the protrusioncontacts the positioning memberto move the positioning memberto a first position. As a result, the positioning membercontacts the substrate Wf to position the substrate Wf.

Furthermore, as shown in, the second holding memberincludes a plurality of power supply contactsfor supplying power to the substrate Wf in contact with an outer peripheral portion of the substrate Wf. Thus, the substrate holder of PTL 1 can supply power to the substrate Wf via the power supply contacts.

As described above, in a substrate holderof PTL 1, a first holding memberand a second holding membersandwich a substrate Wf to hold the substrate Wf. That is, the first holding memberand the second holding memberengage with each other to hold the substrate Wf. In general, for two members to be engaged, clearance is provided so that the two members do not interfere. Consequently, the first holding membermay deviate by an amount of clearance from a designed position relative to the second holding member.

Furthermore, as described above, in the substrate holderof PTL 1, a protrusionincluded in the first holding membercontacts a positioning memberincluded in the second holding memberto move the positioning member. Consequently, if the first holding memberdeviates from the designed position relative to the second holding memberdue to the clearance between the first holding memberand the second holding memberduring positioning of the substrate Wf, the protrusionpushes the positioning memberexcessively, and the positioning membermay be moved closer to the center of the substrate Wf than the designed position. As a result, there is concern that the positioning memberpushes the substrate Wf farther toward the center than the designed position, and the position of the positioned substrate Wf relative to the second holding membermay change. That is, with respect to the second holding member, there is concern that the substrate Wf deviates from a position at which the substrate should be disposed.

Furthermore, in this case, there is concern that power supply contactsincluded in the second holding membercannot contact a predetermined location of the substrate Wf due to the deviation of the substrate Wf. As a result, there is concern that a problem may occur in supplying power to the substrate Wf.

For these reasons, a substrate holder is required in which the positioning memberdoes not push the substrate Wf any farther toward the center than the designed position, even if the first holding memberdeviates from the designed position relative to the second holding member, when positioning the substrate Wf.

Therefore, in view of the above-described problems, one object of the present disclosure is to provide a substrate holder, a plating apparatus and a substrate positioning method in which a centering pin (positioning member) does not push a substrate (substrate Wf) any farther toward the center than a designed position, even if a first holding member (first holding member) deviates from the designed position relative to a second holding member (second holding member), when positioning the substrate.

A substrate holder according to one embodiment includes a first holding member and a second holding member that sandwiches and holds a substrate with the first holding member, the second holding member including a positioning member for positioning the substrate at a predetermined position, and a stopper, the positioning member includes a centering pin movable between a first position and a second position, and is configured so that, when the centering pin moves from the second position to the first position, the centering pin contacts a peripheral edge of the substrate to position the substrate at the predetermined position, the first holding member includes a driving member configured to bias the centering pin toward the first position, when the first holding member and the second holding member hold the substrate, and the stopper is configured to contact the centering pin to stop the centering pin at the first position.

A plating apparatus according to one embodiment is a plating apparatus including a plating tank configured to store a plating solution, the above substrate holder, and a lifting mechanism configured to raise and lower the substrate holder. The substrate holder is configured to hold the substrate having a surface to be plated being directed downward, the second holding member is a support mechanism configured to support an outer peripheral portion of the surface to be plated of the substrate, and the first holding member is a back plate assembly disposed on a back side of the surface to be plated of the substrate, and configured to sandwich and hold the substrate with the support mechanism.

A substrate positioning method according to an embodiment is a method of positioning a substrate with the above substrate holder, the method including a step in which the first holding member and the second holding member sandwich and hold the substrate, a step in which the driving member moves the centering pin from the second position to the first position, a step in which the centering pin positions the substrate at the predetermined position, and a step in which the stopper contacts the centering pin to stop the centering pin at the first position.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are denoted with the same reference signs and duplicate descriptions are omitted.

is a perspective view showing the overall configuration of a plating apparatus of the present embodiment.is a plan view showing the overall configuration of the plating apparatus of the present embodiment. As shown in, a plating apparatusincludes a load port, a transfer robot, an aligner, a pre-wet module, a pre-soak module, a plating module, a cleaning module, a spin rinse dryer, a transfer device, and a control module.

The load portis a module for transferring a substrate stored in a cassette such as a FOUP (not shown) into the plating apparatusand transferring the substrate from the plating apparatusout to the cassette. In the present embodiment, four load portsare arranged side by side in a horizontal direction, and the number and arrangement of the load portsare arbitrary. The transfer robotis a robot for transferring the substrate and is configured to receive and deliver the substrate among the load ports, the aligner, the pre-wet module, and the spin rinse dryer. When the transfer robotand the transfer devicereceive and deliver the substrate between the transfer robotand the transfer device, the substrate can be received and delivered via a temporary stand (not shown).

The aligneris a module for aligning an orientation flat, a notch, or the like of the substrate in a predetermined direction. In the present embodiment, the two alignersare arranged side by side in the horizontal direction, and the number and arrangement of the alignersare arbitrary. The pre-wet modulereplaces air inside a pattern formed on the surface of the substrate with a treatment solution, by wetting the surface to be plated of the substrate prior to a plating process, with the treatment solution, such as pure water or degassed water. The pre-wet moduleis configured to perform a pre-wet process that facilitates supplying of a plating solution into the pattern, by replacing the treatment solution inside the pattern with the plating solution during plating. In the present embodiment, two pre-wet modulesare arranged side by side in a vertical direction, and the number and arrangement of the pre-wet modulesare arbitrary.

The pre-soak moduleis, for example, configured to perform a pre-soak process of etching and removing, with a treatment solution such as sulfuric acid or hydrochloric acid, an oxide film having a large electrical resistance and present on the surface of a seed layer or the like formed on the surface to be plated of the substrate prior to the plating process to clean or activate a plating base surface. In the present embodiment, two pre-soak modulesare arranged side by side in the vertical direction, and the number and arrangement of the pre-soak modulesare arbitrary. The plating moduleplates the substrate. The present embodiment includes two sets of 12 plating modulesincluding three plating modules arranged side by side in the vertical direction and four plating modules arranged side by side in the horizontal direction, so that 24 plating modulesin total are provided, and the number and arrangement of the plating modulesare arbitrary.

The cleaning moduleis configured to perform a cleaning process on the substrate to remove the plating solution or the like remaining on the substrate after the plating process. In the present embodiment, two cleaning modulesare arranged side by side in the vertical direction, and the number and arrangement of the cleaning modulesare arbitrary. The spin rinse dryeris a module for drying the substrate after the cleaning process by rotating the substrate at a high speed. In the present embodiment, two spin rinse dryers are arranged side by side in the vertical direction, and the number and arrangement of the spin rinse dryers are arbitrary. The transfer deviceis a device for transferring the substrate among a plurality of modules in the plating apparatus. The control moduleis configured to control a plurality of modules of the plating apparatusand can include a general computer or a dedicated computer including an input/output interface to and from an operator, for example.

An example of a series of plating processes by the plating apparatuswill be described. First, the substrate stored in the cassette is transferred into the load port. Subsequently, the transfer robottakes the substrate out of the cassette of the load portand transfers the substrate to the aligner. The aligneraligns the orientation flat, notch, or the like of the substrate in the predetermined direction. The transfer robotreceives and delivers the substrate oriented by the alignerto the pre-wet module.

The pre-wet moduleperforms a pre-wet process on the substrate. The transfer devicetransfers the substrate subjected to the pre-wet process to the pre-soak module. The pre-soak moduleperforms a pre-soak process on the substrate. The transfer devicetransfers the substrate subjected to the pre-soak process to the plating module. The plating moduleplates the substrate.

The transfer devicetransfers the substrate subjected to the plating process to the cleaning module. The cleaning moduleperforms the cleaning process on the substrate. The transfer devicetransfers the substrate subjected to the cleaning process to the spin rinse dryer. The spin rinse dryerperforms a drying process on the substrate. The transfer robotreceives the substrate from the spin rinse dryerand transfers the substrate subjected to the drying process to the cassette of the load port. Finally, the cassette containing the substrate is transferred out of the load port.

Next, a configuration of the plating modulewill be described. The 24 plating modulesin the present embodiment include the same configuration, and hence only one plating modulewill be described.is a vertical sectional view schematically showing the configuration of the plating module. As shown in, the plating moduleincludes a plating tankfor storing the plating solution. The plating moduleincludes a membranethat separates an interior of the plating tankin the vertical direction. The interior of the plating tankis divided into a cathode regionand an anode regionby the membrane. The cathode regionand the anode regionare each filled with the plating solution. An anodeis provided on a bottom surface of the plating tankin the anode region. A resistoris disposed opposed to the membranein the cathode region. The resistoris a member for uniformizing the plating process on a surface to be plated (surface to be treated) Wf-a of the substrate Wf and is composed of a plate-shaped member in which multiple holes are formed.

Furthermore, the plating moduleincludes a substrate holderfor holding the substrate Wf having the surface to be plated Wf-a directed downward. The plating moduleincludes a lifting mechanismfor raising and lowering the substrate holder. The lifting mechanismcan be implemented, for example, by a known mechanism such as a motor. The plating moduleis configured to perform the plating process on the surface to be plated Wf-a of the substrate Wf, by immersing the substrate Wf in the plating solution of the cathode regionwith the lifting mechanismand applying a voltage between the anodeand the substrate Wf.

Furthermore, the plating moduleincludes a rotating mechanismfor rotating the substrate holderso that the substrate Wf rotates about a virtual axis of rotation extending perpendicularly in the center of the surface to be plated Wf-a. The rotating mechanismcan be implemented, for example, by a known mechanism such as a motor.

Next, details of the substrate holderof the present embodiment will be described.is a perspective view schematically showing the configuration of the substrate holder of the present embodiment.is a perspective view schematically showing a part of the substrate holder of the present embodiment in an enlarged manner.

As shown in, the substrate holderincludes a support mechanism (second or first holding member)for supporting an outer peripheral portion of the surface to be plated Wf-a of the substrate Wf, a back plate assembly (first or second holding member)for holding the substrate Wf, and a rotary shaftextending vertically upward from the back plate assembly.

The back plate assemblyincludes a disc-shaped floating platefor sandwiching and holding the substrate Wf with the support mechanism. The floating plateis disposed on a back side of the surface to be plated Wf-a of the substrate Wf. Furthermore, the back plate assemblyincludes a floating mechanismfor biasing the floating platein a direction away from the back surface of the substrate Wf, and a pressing mechanismfor pressing the floating plateonto the back surface of the substrate Wf against a biasing force applied by the floating mechanism.

The pressing mechanismincludes a disc-shaped back platedisposed above the floating plateand a flow pathformed inside the back plate. The flow pathincludes a first flow path-extending radially from the center of the back plateto an outer peripheral portion thereof, and a second flow path-extending in the vertical direction to open from the first flow path-to a lower surface of the back plate. The pressing mechanismincludes a diaphragmdisposed in the second flow path-. The diaphragmis a thin film member. The diaphragmhas an outer peripheral portion fixed to the lower surface of the back plateby a fixing member. The pressing mechanismincludes a rodas a form of the pressing member disposed between the diaphragmand the floating plate. The rodhas a lower surface fixed to the floating plateby a bolt, and the rodhas an upper surface in contact with a lower surface of the diaphragm. The rodhas an upper part covered with a capvia the diaphragm. The diaphragmhas a center sandwiched between the capand the rod. A plurality of diaphragms, rodsand capsare provided along a circumferential direction of the back plate assembly. In the present embodiment, an example in which the rodas a separate member from the floating plateis fixed to an upper surface of the floating platehas been described and is not limited thereto and, for example, a protrusion may be formed along the circumferential direction on the upper surface of the floating plate. In this case, the protrusion will have a function as a pressing member similarly to the rod.

The pressing mechanismincludes a fluid sourcefor supplying fluid to the diaphragm. The fluid may be a gas such as air or a liquid such as water. In the rotary shaft, a flow pathextending along the vertical direction is formed, and the fluid sourceis connected to an upper end of the flow path. A lower end of the flow pathis connected to the first flow path-formed in the back plate. The first flow path-extends radially from the center of the back plateand communicates with an upper surface of the capvia the second flow path-. The fluid sourcesupplies fluid to the diaphragmvia the flow pathsand. Then, the capand the rodare pressed downward, thereby pressing the floating platedownward.

The support mechanismincludes an annular support memberfor supporting the outer peripheral portion of the surface to be plated Wf-a of the substrate Wf. The support memberincludes a flangethat protrudes to an outer peripheral portion of a lower surface of the back plate assembly. An annular sealing memberis disposed on the flange. The sealing memberis a member having elasticity. The support membersupports the outer peripheral portion of the surface to be plated Wf-a of the substrate Wf via the sealing member. By sandwiching and holding the substrate Wf between the sealing memberand the floating plate, a gap between the support memberand the substrate Wf is sealed. The sealing memberhaving elasticity is collapsed and has change in thickness a under a pressing force of the pressing mechanismonto the substrate Wf.

The support mechanismincludes an annular clamperheld on the support member. The clampercan raise and lower the back plate assemblyrelative to the support mechanismwhen installing and removing the substrate Wf in and from the substrate holder. The clampercan regulate the back platemoving upward (away from the back surface of the substrate Wf) when fluid is supplied from the fluid sourceto the diaphragm. This respect will be described below.

The back plate assemblyincludes a slide ringprovided in an annular shape on an outer peripheral portion of an upper surface of the back plate. The slide ringis movable in a circumferential direction independently of the back plate. The back plate assemblyincludes a slide plateprotruding from the slide ringtoward the clamper.

For the clamper, a hook-shaped cutoutis formed on a surface facing the slide ring. The hook-shaped cutoutincludes a first grooveextending in the vertical direction so that the slide platecan rise and lower, and a second groovethat communicates with the first grooveand that extends along the circumferential direction of the clamper. On an upper surface of the second groove, an abutment surfaceis formed to abut on an upper surface of the slide platethat moves with the upward movement of the back platewhen fluid is supplied from the fluid sourceto the diaphragm. A plurality of slide platesand cutoutsare provided along the circumferential direction of the substrate holder.

When the substrate Wf is installed relative to the substrate holder, the back plate assemblyis located above the support mechanism. When the substrate Wf is placed relative to the support mechanismin this state, the slide plateis aligned with the first groovein the circumferential direction, and the back plate assemblycan be accordingly lowered relative to the support mechanism. After lowering the back plate assembly, the slide ringis rotated in the circumferential direction to fit the slide platein the second groove. Consequently, the slide plateis opposed to the abutment surface, and the upward movement of the back plate assemblyis accordingly regulated.

The floating mechanismincludes a shaftextending upward from the floating platethrough a through holeof the back plate. The shafthas a lower end fixed to the floating plate. The floating mechanismincludes a flangeattached to an upper portion of the shaftabove the back plate. The flangeis attached to an upper end of the shaftwith a bolt. The floating mechanismincludes a guideprovided in the through hole. The guidehas a hole slightly larger than an outer diameter of the shaftand is attached to an upper end of the through hole. The guideis configured to guide movement of the shaftin a lifting direction. By providing the guide, radial misalignment of the floating plateand the back platecan be inhibited from being caused.

The floating mechanismincludes a compression springattached to an upper surface of the guideand a lower surface of the flange. The compression springmay be provided between the upper surface of the back plateand the lower surface of the flange. The compression springhas a biasing force to lift the flangeupward and therefore biases the floating platein a direction away from the back surface of the substrate Wf via the shaft.

When fluid is supplied from the fluid source, the pressing mechanismpresses the substrate Wf to the sealing memberwith a force stronger than the biasing force applied by the floating mechanism. The pressing mechanismcan change a holding position of the substrate Wf depending on a pressure of the fluid supplied from the fluid source.

As the pressure of the fluid supplied from the fluid sourceincreases, a collapsing amount of the sealing memberincreases, and the sealing membertherefore has a thickness that decreases in proportion to increase in pressure of the fluid supplied from the fluid source. The decrease in thickness of the sealing memberindicates that the holding position of the substrate Wf moves downward and therefore indicates that a distance between the anodeand the substrate Wf shortens. That is, the distance between the anodeand the substrate Wf can be adjusted by adjusting a flow rate of the fluid supplied from the fluid source. Therefore, according to the present embodiment, uniformity of a plating film thickness on the surface to be plated Wf-a can be improved by adjusting the distance between the anodeand the substrate Wf depending on a type of substrate Wf. Furthermore, as shown in, the substrate holderincludes a peeling mechanismconfigured to apply a force to the back surface of the surface to be plated Wf-a of the substrate Wf for peeling the substrate Wf from the back plate assembly.

is a plan view of the support mechanismof the substrate holderof the present embodiment.is a perspective view of the support mechanismof the substrate holderof the present embodiment. As shown in, the support mechanismincludes a plurality of electrical contactsand a positioning member.

Each electrical contactis configured to supply power to the substrate Wf, in contact with the outer peripheral portion of the substrate Wf, when the substrate holderholds the substrate Wf (see). These electrical contactsare attached substantially around an entire circumference of the support mechanism(see). The electrical contactis preferably made of a spring material such as stainless steel. As an example, the electrical contactis configured to elastically contact the outer peripheral portion of the substrate Wf, when the substrate Wf is held with the substrate holder. Specifically, the electrical contactscontact the outer peripheral portion of the substrate Wf while deflecting, when the substrate Wf is held with the substrate holder. Consequently, the electrical contactscan apply a force due to elasticity to the outer peripheral portion of the substrate Wf and securely contact the substrate Wf. Furthermore, as an example, the electrical contactscontact the substrate Wf as much as 95% or more of the substrate Wf in the circumferential direction.

The positioning memberis configured to position the substrate Wf at a predetermined position. In the present embodiment, four positioning membersare arranged at equal intervals on the circumference of the support mechanism(see). However, in another embodiment of the present disclosure, the number and arrangement of the positioning membersare arbitrary. It is particularly preferable that three or more positioning membersare arranged at equal intervals on the circumference of the support mechanism. Hereinafter, the positioning memberwill be described in detail. Note that “positioning” means herein that what is not located at the predetermined position is moved to approach the predetermined position.

is a perspective view of the positioning memberof the present embodiment.is a perspective view schematically showing a part of the substrate holderof the present embodiment in an enlarged manner.is a cross-sectional view schematically showing a part of the substrate holderof the present embodiment in an enlarged manner, when a centering pinis at a second position.is a cross-sectional view schematically showing a part of the substrate holderof the present embodiment in an enlarged manner, when the centering pinis at a first position.

Referring to, the positioning memberincludes the centering pin, a bearing, an elastic member, and two fastening members. As shown in, the positioning memberis fixed to the support memberof the support mechanismwith the two fastening members.

The centering pin, as an example, is a rigid body made of a PEEK material. As shown in, the centering pinincludes a baseextending in a front-rear direction, a clawextending downward from front of the base, and an extensionextending upward from rear of the base. Furthermore, as shown in, the centering pinincludes a rotary shaftextending horizontally from the base. The bearingis then configured to rotatably support the rotary shaft. Consequently, the centering pincan rotate about the rotary shaft. The centering pinis then configured to rotatably move between the first position and the second position. In other words, the positioning memberincludes the centering pinmovable between the first position and the second position.

On the claw, a contact surfacefor contacting a peripheral edge of the substrate Wf is formed (see). As a result, when the centering pinmoves between the first position and the second position, the contact surfacecontacts the substrate Wf to push the substrate Wf. That is, when the centering pincontacts the peripheral edge of the substrate Wf to push the substrate, the positioning memberpositions the substrate Wf at the predetermined position.

Referring to, the back plate assemblyincludes a driving member. Furthermore, the centering pinhas a surface to be pressedlocated on an upper side of the extension. The driving memberis, as an example, a plunger with an elastic body (spring) and is fixed to the back plate. In other words, the driving memberincludes a spring. The driving memberis configured to push the surface to be pressedand to bias the centering pintoward the first position, when holding the substrate Wf with the back plate assemblyand the support mechanism. Consequently, the centering pinmoves from the second position to the first position during holding of the substrate Wf.

Furthermore, as an example, the surface to be pressedis parallel to the surface to be plated Wf-a of the substrate Wf (see). The driving memberis also configured to press the surface to be pressedin a pressing direction perpendicular to the surface to be plated Wf-a of the substrate Wf. That is, the surface to be pressedis orthogonal to the pressing direction of the driving member. Thus, the driving membercan apply, to the surface to be pressed, only a force in an orientation substantially orthogonal to the surface to be pressed. Consequently, when the driving memberapplies the force to the surface to be pressed, the driving memberis unlikely to slip on the surface to be pressed.

If the driving memberslips on the surface to be pressed, the driving memberand the surface to be pressedrub against each other, and the driving memberand the surface to be pressedmay be worn. Then, if the driving memberor the surface to be pressedis worn, the driving membermay not allow the centering pinto move to the first position. Furthermore, particulates may be generated due to friction between the driving memberand the surface to be pressed. However, in the present embodiment, as described above, when the driving memberapplies the force to the surface to be pressed, the driving memberis unlikely to slip on the surface to be pressed. As a result, wear on the driving memberand surface to be pressedis reduced. Furthermore, the generation of particulates due to the friction between the driving memberand the surface to be pressedis also reduced.

Referring to, the elastic memberextends through a stopperand is located inside a holeprovided in the baseand a holeprovided in the support member. The elastic memberis, as an example, a coil spring. The elastic memberis configured to bias a bottom surfaceof the baseupward. That is, the elastic memberbiases the centering pintoward the second position. Consequently, when the driving memberdoes not move the centering pinto the first position, the centering pinis automatically moved to the second position by the elastic member.