TW201404945A - Methods and apparatus for wetting pretreatment for through resist metal plating - Google Patents

Abstract

Disclosed are pre-wetting apparatus designs and methods. In some embodiments, a pre-wetting apparatus includes a degasser, a process chamber, and a controller. The process chamber includes a wafer holder configured to hold a wafer substrate, a vacuum port configured to allow formation of a subatmospheric pressure in the process chamber, and a fluid inlet coupled to the degasser and configured to deliver a degassed pre-wetting fluid onto the wafer substrate at a velocity of at least about 7 meters per second whereby particles on the wafer substrate are dislodged and at a flow rate whereby dislodged particles are removed from the wafer substrate. The controller includes program instructions for forming a wetting layer on the wafer substrate in the process chamber by contacting the wafer substrate with the degassed pre-wetting fluid admitted through the fluid inlet at a flow rate of at least about 0.4 liters per minute.

Description

Method and apparatus for pre-wetting treatment for through-type photoresist plating

The present invention relates to pre-wet device design and methods. In more detail, embodiments relate to a pre-wet device design and method for pre-wetting a wafer prior to depositing a conductive material on a semiconductor wafer for integrated circuit fabrication.

Wetting is an attribute of the liquid/solid interface, depending on the adhesion between the liquid and the solid and the cohesion in the liquid. The adhesion between the liquid and the solid causes the liquid to spread out on the solid surface. Cohesion in the liquid minimizes liquid contact on the solid surface. Wetting of liquids on solid surfaces is important in many industrial processes where liquid to solid surfaces interact. Electroplating (cathode reaction), such as electroplating in the manufacturing process of integrated circuits, is one of such industrial processes. Wetting is also important in anodic reactions such as electroetching and electropolishing.

For example, many semiconductor and microelectronic processes utilize through-type photoresist electrodeposition. This plating process is sometimes referred to as through-mask or photoresist patterned electrodeposition. These treatments can be related to plating submicron gold interconnects on GaAs wafers, electroplating copper coils or magnetic alloys for thin film recording heads, electroplating copper conductors for redistribution or integrated passive applications, or flip chip bonding plating. PbSn or lead-free solder. These processes all involve depositing a metal on a substrate having a blanket conductive seed layer or a conductive plated substrate and a patterned dielectric template.

Methods and apparatus for pre-wet substrates used prior to photoresist plating or other processing are described herein. Pre-wet and clean the substrate to remove dirt including photoresist particles and residues The particulate material is dyed to provide a wetted surface for subsequent processing.

Describe one aspect of the device. The apparatus includes: a degasser for removing one or more dissolved gases from the pre-wetting fluid to generate a degassed pre-wet fluid; and a processing chamber including a crystal for holding the wafer substrate and for rotating the wafer substrate a circular holding portion, a vacuum port for forming a sub-atmospheric pressure in the processing chamber, and a fluid inlet portion coupled to the deaerator, the fluid inlet portion for conveying the degassed pre-wetting fluid to at least about 7 meters per second to On the wafer substrate, the particle material (including particles and residues) on the wafer substrate is released, and the fluid inlet portion is used to transport the degassed pre-wetting fluid to remove the loose particles from the wafer substrate. . The device further includes a controller, the program instructions for rotating the wafer substrate, and by rotating the wafer substrate, contacting the wafer substrate from the degasser and flowing from the fluid inlet portion at a flow rate of at least about 0.4 liters per minute The degassed pre-wet fluid is introduced, and the degassed pre-wet fluid is in a liquid state, so that a wetting layer is formed on the wafer substrate under sub-atmospheric pressure in the processing chamber. The supplied fluid velocity and fluid flow are sufficiently loose to remove particulate material on the substrate and provide a fluid delivery means including a fan nozzle.

The deaerator, in some embodiments, is a membrane contact degasser for producing a degassed pre-wet fluid having a dissolved atmospheric gas of about 0.5 ppm or less for contacting the wafer substrate. The fluid is preferably deionized water or a chemical solution that assists in the release and removal of particles from the wafer substrate. The vacuum crucible is located below the wafer holding portion in some embodiments. The device is used in certain embodiments to maintain a sub-atmospheric pressure of less than about 50 Torr during formation of the wetting layer on the wafer substrate.

In some embodiments, the fluid inlet portion includes a nozzle for delivering a degassed pre-wetting fluid onto the wafer substrate. In some embodiments, the nozzle is disposed on a sidewall of the processing chamber, and in some embodiments, a fan-shaped nozzle for transporting the degassed pre-wetting fluid onto the wafer substrate to cause impacting of the wafer substrate The gas pre-wet fluid has a linear shape. In some embodiments, the fluid inlet portion includes a manifold, and the manifold includes at least one nozzle for conveying the degassed pre-wetting fluid onto the wafer substrate, wherein the nozzle is located above the wafer substrate and is a fan-shaped nozzle for The degassed pre-wet fluid is transported onto the wafer substrate such that the degassed pre-wetting fluid striking the wafer substrate has a linear shape.

In some embodiments, the processing chamber includes a cover and a body, wherein the cover remains stationary, the body is configured to move substantially vertically, the body contacts the cover to form a vacuum seal, and wherein the nozzle of the manifold is attached to the cover. The nozzle of the manifold, in some embodiments, delivers the degassed pre-wetting fluid from one edge of the wafer substrate to the substantial center of the wafer onto the wafer substrate.

In some embodiments, the wafer holding portion is used to hold the wafer substrate face up Oriented, and the device is used to spray pre-wetting fluid from the high speed nozzle onto the wafer substrate.

A typical substrate that can be pre-wetted in this device includes a metal layer and a covered photoresist, wherein the features of the photoresist expose portions of the metal layer. In some embodiments, the photoresist comprises features having an aspect ratio of about 2 to 1 to 1 to 2, wherein the features in the photoresist have openings having a size of between about 5 microns and 200 microns.

In some embodiments, the program instructions of the controller further include: after forming the wetting layer on the wafer substrate, stopping the delivery of the degassed pre-wetting fluid, and stopping the delivery of the degassed pre-wetting fluid, rotating the wafer substrate at different rotational speeds, The degassed pre-wet fluid is drawn to remove excess surface on the wafer substrate.

In some embodiments, the programmed instructions of the controller further include pressurizing the processing chamber to atmospheric pressure or over atmospheric pressure after stopping the delivery of the degassed pre-wetting fluid and before removing excess surface to draw the pre-wetting fluid.

Typically, the program instructions further include instructions to step down the processing chamber to sub-atmospheric pressure prior to forming the wetting layer on the wafer substrate. For example, the program instructions may specify the step of forming a wetting layer on the wafer substrate when the processing chamber pressure drops below about 50 Torr, and contacting the wafer substrate with the degassed pre-wetting fluid for about 10 seconds to 120 seconds.

In another aspect, a system is provided that includes the aforementioned apparatus and a stepper.

In still another aspect, the method includes: (a) disposing a wafer substrate in the processing chamber, the wafer substrate having an exposed metal layer on at least a portion of the surface thereof; and (b) processing the pressure of the chamber Dropping to sub-atmospheric pressure; (c) degassing the pre-wet fluid; (d) rotating the wafer substrate; and (e) contacting the rotating wafer substrate with the degassed pre-wetting fluid at sub-atmospheric pressure in the processing chamber to form Wetting the layer on the wafer substrate, the degassed pre-wetting fluid contacting the wafer substrate at a velocity of at least about 7 meters per second and at least about 0.4 liters per minute to adequately release the particulate material from the wafer substrate and Remove.

In some embodiments, the method further comprises: applying a photoresist to the wafer substrate; exposing the photoresist to the light; patterning the photoresist, transferring the pattern to the wafer substrate; and selectively removing the photoresist from the workpiece.

In another non-transitory computer-readable medium comprising program instructions for controlling a device, wherein the program instructions include the following instructions: (a) providing a wafer substrate in the processing chamber, the wafer substrate having at least one surface on the surface thereof Having an exposed metal layer; (b) reducing the pressure of the processing chamber to sub-atmospheric pressure; (c) degassing the pre-wet fluid; (d) rotating the wafer substrate; and (e) rotating in the processing chamber Contacting the rotating wafer substrate with a degassed pre-wetting fluid at atmospheric pressure to form a wetting layer on the wafer base On the plate, the degassed pre-wet fluid is at a rate of at least about 7 meters per second (to sufficiently loosen any particulate material on the exposed metal layer) and at least about 0.4 liters per minute (to remove enough pine from the wafer substrate) The removed particulate material) contacts the wafer substrate.

301‧‧ ‧ chamber

303‧‧‧vacuum pump

305‧‧‧ valve connection

306‧‧‧degassing loop

307‧‧‧ fluid tank

309‧‧‧Degassing device

311‧‧‧

313‧‧‧Three-way valve

315‧‧‧ valve

317‧‧‧needle valve

501‧‧‧Pre-wet chamber

503‧‧‧Motor

504‧‧‧Bottom of the chamber

505‧‧‧Motor and bearing support members

509‧‧‧Couplings

511‧‧‧ drive shaft

513‧‧‧The bottom of the chuck

515‧‧‧ Arm

517‧‧‧Alignment equipment

519‧‧‧Exporting Department

521‧‧‧Vacuum inlet and vacuum release line

523‧‧‧ protective cover

525‧‧‧Pre-wet fluid nozzle

527‧‧‧chamber vacuum door

601‧‧ ‧ chamber

603‧‧‧ wafer

605‧‧‧Cooling element

607‧‧‧ Holding Department

609‧‧‧vacuum cover

611‧‧‧ pipeline

613‧‧‧ pipeline

615‧‧‧ Entrance Department

617‧‧‧ Sealing Department

619‧‧‧ Container

701‧‧‧ wafer

702‧‧‧ Wafer Holding Department

703‧‧‧室

705‧‧‧Motor

707‧‧‧vacuum

709‧‧‧埠

711‧‧‧ Entrance Department

713‧‧‧Pre-wetting fluid

801‧‧‧Pre-wet chamber

803‧‧‧ Wafer Holding Department

805‧‧‧Motor

807‧‧‧vacuum

809‧‧‧ wafer

811‧‧‧埠

813‧‧‧ fluid

901‧‧‧ chamber

903‧‧‧ slot wall

905‧‧‧ Wafer Holding Department

907‧‧‧High impedance virtual anode

909‧‧‧Separate anode chamber area

911‧‧‧vacuum

913‧‧‧ plating solution

915‧‧‧ wafer

1001‧‧‧Electroplating system/module

1003‧‧‧Robot

1004‧‧‧Robot

1005‧‧‧Loader

1013‧‧‧Pre-wet chamber

1015‧‧‧Module

1021, 1023, 1025‧‧‧ plating bath

1100, 1150, 1200, 1600‧‧‧

1105, 1115, 1155, 1160, 1165, 1170, 1605, 1610, 1615, 1620, 1625‧ ‧ steps

1350‧‧‧Pre-wet chamber

1352‧‧‧Cell body

1354‧‧‧Case cover

1356‧‧‧ Holding Department

1358‧‧‧ wafer substrate

1360‧‧‧vacuum

1362‧‧‧ Entrance Department

1364‧‧‧Nozzles

1366‧‧‧Pre-wetting fluid

1400‧‧‧Pre-wet chamber

1402‧‧‧ chamber body

1404‧‧‧Case cover

1406‧‧‧ Holding Department

1408‧‧‧ wafer substrate

1410‧‧‧vacuum

1412‧‧‧ Entrance Department

1414‧‧‧Nozzles

1416‧‧‧Management

1418, 1420‧‧‧埠

1422‧‧‧Pre-wetting fluid

1500‧‧‧Pre-wet chamber

1502‧‧‧ chamber body

1504‧‧‧Case cover

1506‧‧‧ Holding Department

1508‧‧‧ wafer substrate

1510‧‧‧vacuum

1512‧‧‧ Entrance Department

1514‧‧‧Nozzles

1516‧‧‧Management

1518, 1520‧‧‧埠

1522‧‧‧Pre-wetting fluid

Figure 1 depicts a simplified diagram of one embodiment of a pre-wet device.

2 is a perspective cross-sectional view of an embodiment of a pre-wet chamber.

Figure 3 illustrates an embodiment of a pre-wet chamber for performing a coagulation pre-wet treatment.

Figure 4 illustrates an embodiment of a pre-wet chamber for performing an immersion pre-wet treatment.

Figure 5 illustrates another embodiment of a pre-wet chamber for performing an immersion pre-wet treatment.

Figure 6 illustrates an embodiment of an apparatus for pre-wetting treatment in a plating bath.

Figure 7 illustrates an embodiment of an electroplating system.

Figures 8a, 8b are flow diagrams of a pre-wet processing embodiment.

Figure 9 is a flow diagram of an embodiment of a plating process for plating a layer of metal on a wafer substrate.

Figures 10a, 10b are embodiments of a pre-wet chamber through a photoresist plating.

Figures 11a, 11b are embodiments of a pre-wet chamber through a photoresist plating.

Figure 12 illustrates an embodiment of a pre-wet chamber through photoresist plating.

Figure 13 is a flow diagram of an embodiment of a pre-wet treatment through photoresist plating.

Specific embodiments are described. Examples of specific embodiments are illustrated in the drawings. The invention has been described in terms of specific embodiments, but is not limited thereto. Instead, any alternatives or means, modifications, and equivalents are intended to be within the scope of the invention. In the following, in order to explain the present invention in more detail, many detailed and specific examples will be utilized. The invention may be practiced without all or a portion of these details. In other instances, well-known processes and the like are not described again in order to unnecessarily obscure the present invention.

Disclosed herein are wafer pre-wet device designs and methods for correcting wafer entry and wafer processing conditions and pre-wetting fluid composition during plating. According to this embodiment, the pre-wetting treatment can be performed in the plating chamber or in a module including a pre-wet processing station and a plating processing station. The separate pre-wet processing stations are executed. In some embodiments, pre-wetting and plating are performed in different equipment.

The substrate is typically a semiconductor substrate having a conductive material thereon (eg, a seed layer containing copper or a copper alloy). During electroplating, the electrical connection is connected to the conductive layer, and a negative bias is applied to the wafer substrate, thereby serving as a cathode. The wafer is contacted with a plating solution containing a metal salt such as copper sulfate, copper sulfonate or a mixture of salts, and the metal salt is reduced at the cathode of the wafer to deposit the metal on the wafer. In many embodiments, the substrate contains one or more recess features (such as through holes or holes) that need to be filled with a plating process. In addition to the metal salt, the plating solution may also contain an acid, and usually contains one or more additives such as halides (such as chlorides, bromides, etc.), accelerators, leveling agents, and inhibitors to adjust various substrates. The plating rate of the surface.

The processing and related device design of the present invention is particularly applicable and it is necessary to electrically fill a wider (e.g., typically greater than 5 μm) deeper (e.g., typically greater than 10 μm) damascene structure (through holes), as is common in emerging copper bore perforated (TSV) electricity. Filler structure or recess feature associated with through-type photoresist plating. For a description of the perforated structure, reference is made to U.S. Patent No. 7,776,741 (issued on August 17, 2001), which is incorporated herein by reference. The gas bubbles trapped or present on the surface or inside of the feature, whether by blocking the surface of the feature with a non-conductive gas or obstructing the free flow of current, will interfere with the plating of the field and features. deal with. The disclosed method and associated equipment design ensures a void-free copper fill.

There are some difficulties in electroplating and electrical filling of TSVs and through-type photoresists, including long plating times due to very large and/or deep structures, or poor plating due to poor wetting of features or poor coverage of seed layers. . Furthermore, it is important to ensure that the interior of all of the recess features are filled with liquid and that no bubbles are trapped inside the features to prevent internal plating. The pre-wet device design and method described herein is typically directed to metal (especially copper) electroplating (cathode reaction). However, the pre-wet device design and method described herein is applicable to all electrolytic reactions, including electroetching and electropolishing, both of which are anodic reactions.

Here, a method for forming a liquid-filled, bubble-free, particle-free recess feature required for the plating process will be described. Furthermore, the composition of the pre-wet fluid which minimizes the erosion of the seed layer while increasing the plating rate is also illustrated.

The apparatus and method described herein by first removing gas (mainly non-condensable gases such as nitrogen or oxygen) from the features prior to pre-wetting the surface and features with the fluid, Avoid forming bubbles in the recess features (such as through holes) on the wafer substrate. To achieve this effect, the wafer with the recess features is placed in a container (such as a vacuum container) suitable for both holding the wafer and allowing gas to be removed from the wafer surface. In addition to the container itself, a mechanism for removing the gas (such as a line connected to a vacuum source such as a pump) and a mechanism for depositing liquid on the surface while maintaining a vacuum state are also required.

The various device designs described herein are wafer pre-wetting performed prior to or immediately after the start of the plating process to avoid trapping of bubbles and gases within the recess features in the surface. Embodiments of the pre-wet device include various components. Typically, the pre-wet device includes a pre-wet fluid reservoir and a recovery tank, including a liquid mixing device and a level controller and sensor. In some embodiments, the apparatus includes a pre-wet fluid removal loop. The degassing circuit includes a circulation pump, a bypass/branching valve, a liquid degassing element, and a liquid degassing element and a system vacuum pump (a liquid degassing element for evacuating and applying a vacuum to the tool and the pre-wetting chamber) ) The link between. The pre-wet device also includes a pre-wet chamber. In some embodiments, the pre-wetting chamber includes a two-position (open/close) vacuum wafer access door or cover for accessing the chamber, and preventing liquid from escaping to the upper wall or door and dropping onto the wafer surface. The combined door or cover is attached to the splash baffle. In some embodiments, within the chamber is a wafer holder that holds the wafer within the chamber and rotates it. In some embodiments, the chamber includes a dome chamber heater to prevent liquid from condensing on the chamber wall and above the wafer and vacuum wafer access gates, possibly dropping onto the wafer. The pre-wetting chamber typically includes an inlet port for allowing pre-wetting fluid to enter the chamber and directing the pre-wetting fluid onto the upper surface of the rotating wafer, and an inlet line and chamber port for introducing and releasing a vacuum to The chamber, the inlet line includes a particle filtration device, and the inlet port includes a flow diffuser for dispersing the inflow gas stream and minimizing turbulent flow in the chamber. In some embodiments, the chamber includes a level sensor for monitoring the condition of the empty/prepared and full/over full tank. The pre-wetting chamber also typically includes a drain to remove liquid from the chamber and direct the drained liquid back to the reservoir.

The embodiments described herein address the deleterious effects of trapping bubbles, particularly those that can form in larger through holes or trenches in the wafer by: (1) by removing the wafer And substantially non-condensing gas at all atmospheric pressures in the through-hole or hole to completely prevent gas from being trapped in the through-hole during pre-wetting, and then pre-wetting the wafer with a pre-wet fluid; and/or (2) by application The relatively large external pressure on the fluid greatly increases the bubble dissolution rate, thereby creating a highly supersaturated state at the bubble interface that drives the bubbles to dissolve in the fluid. In addition to these pre-wetting and pre-plating measures, in some embodiments, electroplating is performed in a plating solution maintained in a degassed state, while in other embodiments In the embodiment, the plating solution is degassed in the pipeline before it contacts the surface of the wafer.

In some embodiments, it is possible to pre-wet in the plating bath, the composition of the pre-wetting fluid being the same as the plating solution. However, due to various factors, including the combination of electroplating and vacuum processing, the hard structure tends to be complicated. Pre-wet (including vacuum feature backfill pre-wet) is usually in a different pool and sub-cell than the electroplating pool. Or in the module. The composition of the pre-wet fluid can be selected when the pre-wetting is carried out under vacuum in a completely different area of the plating bath or in a module that is completely separate from the plating bath, rather than in a plating solution. The pre-wetting fluid can have the same or very similar composition as the fluid used to electroplate the wafer. The pre-wetting fluid may comprise all of the components of the electroplating bath, such as having the same solvent or solvents, the same dissolved metal ions, acids, cations, additives, halides, and being at the same or very similar concentrations to the plating solution. Such pre-wetting fluids can be implemented in certain embodiments. Alternatively, in other embodiments, a pre-wetting fluid that is very different from the plating solution can be used. As in some embodiments, the pre-wetting fluid can be: 1) water; 2) a metal ion concentration that is substantially higher than the substantially higher concentration of the plating solution; 3) a lower concentration of halides, a different combination of halides, a fluid that does not dissolve any of the three states of the halide; 4) a fluid that is substantially lacking one, some or all of the plating additive; or 5) a solvent that is miscible with water. These pre-wetting fluids will be described below.

Several factors should be considered when selecting the pre-wetting fluid composition, including the following possibilities: a) etching the metal layer on the wafer substrate prior to initiation of plating; b) inhibiting the plating process (even if it slows down or completely inhibits the feature metal filling process) ; c) pre-wetting fluid loss upon repeated use of the pre-wet fluid; and d) varying the concentration of various key species in the plating solution over time (by addition, dilution or enrichment). The last treatment of the above process can change the metal ion concentration, halide concentration, organic additives, etc. in the plating solution. These effects can be quite substantial. Furthermore, when a pre-wet fluid having a composition different from that of the plating solution is used, if the pre-wet treatment is performed in the same module, no appropriate mechanism is used to remove and recover the excess entrained pre-form to be added to the plating solution. Wet fluids typically require mechanisms for mitigating, monitoring, and/or even correcting plating solutions over time. On the other hand, for the hardware and process used, the pre-wet operation is in a sub-vessel of separate processing stations, modules, vessels or plating baths, and this fluid can be separated and recycled, due to It is more advantageous to avoid the aforementioned problems. With this premise, and in order to simplify the core concepts of the described embodiments, many embodiments herein refer to separate pre-wet "station" and separate "plating stations", while wafers are transferred from the former to the latter. . But perhaps in some situations it is beneficial (such as to avoid not Mixing with liquids or for other reasons) is not intended to limit the invention insofar as it relates to specific pre-wet materials, commonly used fluids, and electroplating treatment sequences.

1 is a diagrammatic view of one embodiment of a pre-wet device (i.e., chamber 301 and associated hardware). The chamber 301 is connected to the vacuum pump 303 via an outlet portion in the chamber and through the three-way valve connection 305. On the other side of the three-way valve is a degassing loop 306, which includes a pre-wet fluid tank 307, a deaeration device 309, and a pump 311 for circulating the pre-wet fluid in the degassing loop. In another embodiment, the pre-wet fluid supply line is connected to the vacuum line only in the chamber, and each line has its own valve (ie, no three-way valve). In an alternative embodiment, the chamber has an inlet for supplying pre-wetting fluid and an outlet for connecting the vacuum pump. If the pump is to be used to drive fluid into the chamber, rather than by a pressure differential between the pre-wet fluid reservoir 307 and the chamber 301, the pump 311 can be positioned behind the degassing element.

In some embodiments, a vacuum is applied to a reservoir (not shown) with a vacuum pump to remove gas from the pre-wet fluid reservoir 307 region to achieve a minimum amount of dissolved gas. The rate at which gas is removed from the pre-wet fluid can also be increased by increasing the exposure of the fluid to the surface of the vacuum, such as by allowing the fluid to re-enter the chamber from the circulation loop by spraying or spraying the column. In this embodiment, the pre-wetting fluid is circulated through the addition to the pre-wet before prewetting fluid removing one or more dissolved gases (e.g., both O ₂ and N ₂₎ an embodiment of the system shown in FIG. Gas device 309 (as in some embodiments is a membrane contact degassing device). Examples of commercially available degassing means may include U.S. NC, Charlotte the Membrana sold Liguid-Gel ^TM, and U.S. Minnesota, Chaska of Entegris sold pHasor ^TM. The amount of dissolved gas can be monitored by a suitable instrument, such as a commercially available dissolved oxygen gas (not shown). As illustrated herein, the removal of dissolved gases prior to entering the chamber 301 by the pre-wetting fluid improves the pre-wet treatment. Optionally, after degassing the pre-wet fluid, the valve 315 between the degassing chamber 309 and the vacuum side of the vacuum pump 303 can be closed (this prevents the gas originally in the chamber from dissolving in the degassed state). In a pre-wet fluid; in some embodiments, these two functions can be performed with separate pumps).

Unlike the state of the device using a configuration similar to that of Figure 1, the pre-wet fluid is degassed before it is exposed to the vacuum in the vacuum, and the dissolved gas from the fluid when the fluid enters the chamber. Will be released from the fluid. This causes bubbles to form in the through holes. Without being limited by a particular model or theory, the bottom of the through-hole is the location of a negative curvature, and this location is generally considered to be particularly susceptible to bubble formation and release of gas from the pre-wetting fluid. If this happens, bubbles will form from the pre-wet fluid containing dissolved gases, because The gas in a wet state (such as a vacuum in a chamber) is supersaturated. The bubbles thus formed are still present after the pre-wetting treatment, and thus the plating is suppressed at the presence, causing related defects. Thus, in certain embodiments (including the embodiment of Figure 1), the pre-wet fluid used for the pre-wet treatment is a pre-wet fluid after degassing. In some embodiments, the degassed pre-wet fluid can be a plating solution, and the pre-wetting methods described herein can be performed in the same electroplating chamber. If separate pre-wet chambers and equipment are used, but the pre-wetting fluid is not degassed, intermittent and unreliable filling results may be observed. For example, when the pre-wet fluid is degassed and the pores of the wafer are filled with pre-wetting fluid (wafer in vacuum), it has been found that 15% of the pores have air bubbles in them (with the same percentage of plating) The void also means that bubbles are trapped in the pores). Thus, in certain embodiments, it is important to perform pre-wetting in a vacuum (i.e., below atmospheric pressure) and to use a degassed fluid.

Conversely, performing a pre-wet operation in a vacuum while utilizing a degassed pre-wet fluid can result in a more substantially reduced feature void in certain embodiments than would be the case if the moisture was only pre-wet in a vacuum. In a particular embodiment where there is a relatively good exemption condition for the formation of uneven deposits, the combination of the degassed pre-wet fluid and the pre-wet under vacuum is further combined with electroplating in a degassed plating solution. The plating solution can be degassed only during the initial stage of electroplating (as in the first 10 minutes of the electroplating process), or maintained in a degassed state throughout the plating process (eg, when the plating time is longer). In the experiments conducted under these conditions, the through holes produced were gapless.

Returning to Fig. 1, when the pressure of the chamber 301 reaches a low pressure value (i.e., the sub-atmospheric value), the three-way valve 305 connected to the vacuum pump is switched to be connected to the line from the degassing loop 306, and The three-way valve 313 of the gas loop is configured to allow fluid to be introduced into the vacuum chamber 301. In some embodiments, the subatmospheric pressure is approximately equal to the boiling pressure of the pre-wetting fluid at the operating temperature, and the boiling pressure of the water at ambient temperature is about 20 torr. In other embodiments, the subatmospheric pressure is about 50 torr. In still other embodiments, the pressure of 50 torr is maintained while pre-wetting the wafer substrate. In an alternate embodiment, the pre-wet system is configured to initiate introduction of the pre-wetting fluid into the chamber and onto the wafer substrate when the chamber pressure is reduced to about 50 Torr or less. In embodiments where the pre-wet fluid tank 307 is at atmospheric pressure, liquid is introduced into the chamber 301 by a pressure differential between the vacuum chamber and the pre-wet fluid tank.

The pre-wetting fluid wets the surface of the wafer on the device side of the wafer within chamber 301. Needle valve 317 can be used to measure the pre-wet fluid flow into chamber 301. Embodiments of the chamber 301 are described herein. As explained herein, in some embodiments, the chamber 301 is a pressure chamber for external pressure Applied to increase the gas run dissolution rate. In other embodiments of the pre-wet device, the pre-wet device includes a transport mechanism for transporting the wafer substrate from the pre-wet chamber to the electroplating apparatus.

In certain embodiments, the pre-wetting fluid is cooled prior to injection into the pre-wet chamber (eg, water at 0 degrees C, or a suitable electrolyte at -10 degrees C). In other embodiments, the degassing device is used to cool the pre-wet fluid to a temperature of less than about 20 degrees C. Examples of other methods of cooling the pre-wet fluid include passing the fluid through a pre-wet fluid storage tank or through an in-line cooler (both not shown in Figure 1). Cooling the pre-wet fluid reduces the partial pressure of the pre-wet fluid solvent, allowing greater vacuum energy to be applied to, for example, the degassing device. Decreasing the temperature of the pre-wet fluid can also effectively increase both the surface tension and the viscosity of the pre-wet fluid, which generally reduces the phenomenon of "blow through" or "weeping" of the degassing device. Drip leakage is particularly a problem when handling pre-wet fluids containing salts because the drip-containing salt-containing fluid tends to dry and break the pores of the degassing device. The use of lower temperature fluids mitigates the possibility of evaporation and flow of the salt-containing electrolyte, avoiding known problems with degassing devices. For example, the gaseous pressure of water (containing a small amount of salt) is about 2.7 torr (-10 degrees C), relative to 17.5 torr at 20 degrees C, 32 torr at 30 degrees C. When a vacuum of 20 torr (which produces about 0.5 ppm of dissolved atmospheric gas) is applied to the deaerator, the 30 ° C pre-wet fluid will actually boil, leaving the salt in the pores of the degassing device, and 20 The pre-wetting fluid of degree C will evaporate quickly. However, when a pre-wet fluid of -10 ° C is used, the salt residue of the degassing device becomes very small. Thus, in general, fluids at lower temperatures can more efficiently remove more dissolved gases from the degassing device. In certain embodiments, the pre-wet fluid is cooled to a temperature of less than about 20 degrees C, such as 0 degrees C or less, before it is degassed and before it enters the processing chamber. In addition, reducing the temperature of the pre-wet fluid reduces the rate of metal erosion in the pre-wet system.

In some embodiments of the pre-wet device, the wafer surface is wetted with a pre-wetting fluid, followed by application of external pressure to the fluid. The wafer surface is first contacted with the fluid using a suitable mechanism, typically by immersing the wafer in a pre-wetting fluid (described below). In these embodiments, the pre-wetting chamber includes an inlet portion for introducing a pre-wet fluid and a chamber for operating at a pressure higher than normal pressure during or after pre-wetting. Applying external pressure to the fluid assists in the removal of air bubbles. In some embodiments, the pre-wetting fluid is pretreated to substantially contain not only oxygen (e.g., to minimize metal attack on the wafer) prior to pre-wetting the surface, nor does it contain all types. Dissolve non-condensable gases, such as nitrogen and carbon dioxide, to accelerate the gas dissolution rate of any trapped features in the recess. Described in order to process semiconductor wafers in U.S. Patent Nos. 6,021,791 and 6,146,468, the disclosures of each of which are incorporated herein by reference. The wafer is exposed to a deoxidized treatment fluid.

After immersing the wafer in the pre-wet fluid or covering the wafer with the pre-wetting fluid, the area surrounding the wafer is closed and hermetically sealed (eg, a pressure chamber) and an external pressure is applied to the chamber and fluid. The application of pressure can be pneumatic (such as directing high pressure gas to the area of the fluid in the chamber), or hydraulically (e.g., leaving the chamber substantially free of undissolved gas and applying external pressure to the fluid using a hydraulic piston or other suitable device). As the chamber pressure increases, the bubbles shrink from their original size. When pneumatic (gas) pressure is used to compress trapped bubbles, it is important to avoid the dissolution of a substantial amount of gas into the pre-wet fluid, especially around the bubbles. In some embodiments, a stagnant, relatively thick fluid layer is used, such as thicker than 1 cm. In other embodiments, a pneumatic tube is applied to the chamber via a long tube having the ability to dissolve the substantially resistive gas to the interface, allowing the gas to contact the unition over a relatively small surface area, and having a relatively long diffusion path, limiting the gas The amount that can be dissolved in the fluid over a period of time. Regardless of how the pressure is applied, the driving force for dissolving the trapped bubbles increases with the applied pressure. For large bubbles without significant capillary pressure effects, the driving force for dissolution is approximately equal to the product of the initial molar fraction of a particular gas component in the bubble; and the pressure applied to the chamber and the initial partial pressure of dissolved gases in the fluid. difference between. The value of the latter will vary depending on the degree of degassing of the pre-wet fluid.

Although the pressure can be applied pneumatically or hydraulically, in the absence of a pre-wet embodiment of the impregnation embodiment, but with a thin layer of pre-wetting fluid on the wafer, the external pressure applied by the pneumatic may cause the gas to redesolve quickly. In a thin layer of pre-wetting fluid (such as degassed). There is competition between the intake air from the external pressurized gas source and the gas dissolved from the bubbles into the liquid. Therefore, a relatively thick layer of pre-wet fluid should be used in the non-immersion pre-wet operation. In addition, the application of hydrostatic pressure to a thin layer of pre-wet fluid on the wafer also has a number of implementation mechanisms. One possible mechanism is to create a face-up wafer and a cup containing a pre-wet liquid fluid. Conversely, for thick layers of pre-wet fluids and immersion pre-wetting methods, the allowable error can be much larger. This is because the pressure can be conducted to the bubble by a mechanism that is simply a hydrostatic pressure, or the application of the pneumatic pressure does not rapidly resaturate the pre-wetting fluid surrounding the bubble in the through hole of the gas.

When pressure is applied, if the partial pressure of gas in the bubble exceeds that of the pre-wet fluid, the bubble will begin to dissolve. Eventually the bubbles will completely dissolve and the total time of dissolution will depend on the parameters such as the original size of the bubble, the applied pressure and the original depth of the bubble within the feature. After the bubble is completely dissolved, it should be allowed to wait for a period of time before releasing the pressure, so that any excess dissolved gas (super The amount that can be dissolved at 1 atmosphere is entered into the pre-wet fluid to achieve an overall balance. When this step is performed, the bubbles can be removed from the features and will not be formed again when more than the external pressure is released.

2 illustrates the actual application of a pre-wet chamber for performing the pre-wet method described herein. A non-perspective perspective view of the embodiment. The pre-wet chamber 501 includes a motor 503 for rotating the wafer during processing. The motor is positioned below the chamber by a collet of the chamber bottom 504, which utilizes a motor and bearing support member 505. The bearing is a commercially available vacuum shaft through which the central axis rotates. The motor is attached to the drive shaft 511 by a coupling member 509 that passes through the vacuum isolation bearing to the chuck bottom 513. The collet has three arms (one of the arms of 515) to support the wafer (not shown), a restriction pin, and other suitable alignment devices 517.

Located in the lower portion of the chamber is a discharge portion 519 for removing excess pre-wetting fluid that will accumulate in the lower portion of the chamber after application to the rotating wafer. The fluid is forced to the chamber wall and dripped to the bottom of the chamber. In some embodiments, a "fluid-deflecting guard" (not shown) around the wafer is disposed on the same plane as the wafer to contact the fluid flowing from the edge of the wafer into the chamber. The wall is folded downwards. The deflecting guard can be movable or the wafer and wafer chuck can be adjusted by a suitable vertical moving mechanism and seal. Also located at the bottom of the chamber is a vacuum inlet and vacuum relief line 521, which in some embodiments is covered by a protective cover 523. This protective cover is used to prevent gas rushing from causing unnecessary disturbance to the fluid within the chamber and to minimize the amount of liquid entering the vacuum line by separating the two regions. While the vacuum line (and shield) can be located in the upper portion of the chamber, it is advantageous to introduce vacuum from below the wafer, minimizing the tendency of any particles to fall onto the wafer to form defects. This condition can occur if the chamber or chamber is opened by a gas, or if the chamber door is opened and the particles or other materials enter the chamber from a normal pressure environment. In order to minimize the entry of particles and other materials into the chamber, the chamber is typically backfilled, and the particles are filtered with an inert gas such as nitrogen, carbon dioxide or argon, and a clean, particle-free gas of a slightly positive pressure is delivered as the chamber door opens. The backfill gas is typically filtered and the incoming fluid enters a flow diffuser mounted on the chamber wall to prevent the formation of a gas jet spray column that may dry the wafer or undesirably disturb the contents of the chamber.

In some embodiments, the pre-wet fluid nozzle 525 is disposed above the wafer and wafer chuck and is located on its side rather than directly above it, oriented to spray fluid or to direct fluid flow to the wafer center. region. In other embodiments, the pre-wet fluid nozzle is coupled to a movable arm that is movable over the wafer. In the embodiment of Figure 2, the chamber vacuum door 527 is disposed along the chamber wall and serves to hermetically seal the chamber itself. It can be removed from the chamber or moved down (or up) to free the wafer Ground into the chamber and it can be repositioned to an airtight position after the wafer is placed on the wafer chuck. Doors and other components may be contaminated with fluid, so they should be designed to prevent fluid from dripping onto the wafer. For example, the retracted position of the door and associated hardware may be located below the plane formed by the wafer as it is fed into the chamber such that the dripping fluid or the like contaminates the wafer as it is fed into or out of the chamber.

In some embodiments, the upper region of the chamber, particularly the region above the plane where the wafer is located at the chuck and withdrawn through the door, is heated to a temperature that exceeds the circle of the pre-wet crystal. This includes both the area above the wafer (the topmost surface or vacuum top, not shown in Figure 2) and the surrounding area around the wafer. This heating helps to prevent liquid from dripping from the ceiling of the chamber to the surface of the wafer before forming a vacuum environment, so that bubbles may be trapped in the through holes at the drop, so that only when the through holes are removed The desired treatment failure of the pre-wetting fluid onto the wafer is applied to the air. Similarly, the liquid dripping from the chamber wall to the surface of the wafer during the placement of the wafer into the chamber will have a similar effect. By heating the chamber walls, condensation can be prevented from occurring on the walls of the chamber and the ceiling, and any individual droplets that may reach these locations can be quickly evaporated, thereby keeping these areas dry.

Although not shown in FIG. 2, in some embodiments, a vertically movable auto-splash panel is disposed within the chamber and around the wafer and the collet. The splash plate can be displaced upwards at the time of application of fluid or other timing to minimize and prevent fluid from contacting the chamber door or upper wall or the like. Alternatively, the wafer chuck can be displaced downwardly into the chamber until the wafer is fed below the plane of the vacuum door, thus achieving the same purpose.

In other embodiments, the pre-wet fluid is not sent to the surface of the wafer, but the wafer is immersed (or otherwise covered by the wafer, such as by condensing) in the pre-wet fluid, while in the fluid and wafer. Maintain a vacuum above. Since the creation of a vacuum in the chamber creates a substantially non-condensable gas in the chamber, the pre-wet fluid does not become obstructed when it enters the through-hole. In other words, the liquid does not need to be displaced by any gas located in the through-holes during pre-wetting because the gas has been removed in another separate process (vacuum) prior to the pre-wet treatment.

For example, in one embodiment, after vacuum is applied to the pre-wet chamber, condensable fluid vapor is generated within the chamber or introduced into the chamber (eg, water vapor (eg, low pressure vapor), methanol, dimethyl carbonate) , diethyl carbonate, isopropyl alcohol, dimethyl sulfoxide, dimethyl formamide or other liquid which can be used as a subsequent electroplating electrolyte, which is followed by It is easily dissolved during rinsing or soluble in subsequent electroplating electrolytes). In an embodiment, if the wafer substrate has at least one recess feature, and The pre-wet chamber is used to deliver the pre-wet fluid to the wafer substrate in a gaseous state, the pre-wet fluid will condense to form a liquid film on the wafer surface, and the recess feature is filled with the pre-wetting fluid. Figure 3 illustrates an embodiment in which a pre-wet chamber is used to perform such a coagulation pre-wet treatment. 3 illustrates the chamber 601 having a removable vacuum cover (or access door) 609 that allows access to the chamber, a line 611 to the vacuum source, a vacuum release line 613, and a condensable fluid inlet portion 615. The vacuum seal portion 617 seals the lower vacuum containing container 619 from the other portions of the chamber. The wafer 603 is positioned on a wafer cooling element (cooler) 605 that is part of the wafer holding portion (clamp) 607. The wafer cooling element 605 lowers the wafer substrate surface temperature to a lower condensation temperature than the pre-wet fluid flowing into the chamber via the inlet portion 615 in a gaseous state. In another embodiment, after a vacuum is created and a condensable gas, such as air, is removed from the chamber 601 by vacuum, the water is directly heated to evaporate (ie, boil) within the chamber and cause it to The chamber is condensed on the surface including and preferably on the cooler wafer 603. For example, in a chamber without a vacuum seal 617, a small amount of water in the lower chamber region 619 can be heated to cause a boil while pulling the vacuum into the chamber. The line connected to the vacuum can be removed (closed) at some point during processing.

In another embodiment, the wafer substrate is immersed in a bath of pre-wetting fluid for a period of time. Figure 4 illustrates an embodiment of a pre-wet chamber for this immersion pre-wet treatment. In FIG. 4, the wafer 701 is held in the wafer holding portion 702 in the chamber 703. The chamber 703 has an inlet portion 711 that introduces a pre-wetting fluid. As shown, the wafer is held by the wafer holder and faces up, and is held by a suitable mechanism to allow fluid to reach the wafer from the peripheral edge. Vacuum is drawn from chamber 703 into chamber 703, which is connected to a vacuum system (not shown). Next, the method of pre-wetting the wafer from the pre-wet fluid may be as follows: 1) the wafer and wafer holding portion moves downward into the pre-wet fluid 713; or 2) the pre-wetting fluid enters from the inlet portion 711 to lift the fluid Liquid level. During the pre-wet process, the wafer can be rotated slowly with the motor 705. After the pre-wet treatment, the liquid level is lowered or the wafer is raised, and the wafer is rotated by the motor 705 at a low speed rpm to remove excess fluid, leaving a thin layer of pre-wetting fluid. Nitrogen may also flow into the crucible 709 to dry the back side of the wafer while the front side of the wafer remains wet. The wafer is then fed into a standard grab loader (clamshell) for electroplating.

In other embodiments of the pre-wet chamber shown in Figure 4, the wafer can be held face down. In certain pre-wet device embodiments containing the pre-wet chamber shown in Figure 4, after the chamber pressure has been reduced below about 50 Torr, the pre-wet device is activated to immerse the wafer in the pre-wet fluid. The pre-wet chamber 703 of Figure 4 can be used in embodiments that use external pressure to dissolve bubbles, as described herein. In addition to being able to withstand vacuum, or if it is not subjected to a vacuum, the chamber and other components must be able to withstand internal pressure.

Figure 5 illustrates another embodiment of a pre-wet chamber of the immersion pre-wet treatment. FIG. 5 illustrates a pre-wet chamber 801, a wafer 809, and a fluid 813 or wafer holder 803 that can move relative to each other. In this embodiment, the chamber and wafer holder 803 can be tilted to precisely control the pre-wet front and ensure complete removal of fluid from the chamber. In addition, the gap between the wafer 809 and the bottom of the chamber is small. As with Figure 4, the pre-wetting fluid of Figure 5 can enter/exit from the crucible 811, the vacuum can be drawn from the vacuum crucible 807 into the chamber, and the vacuum crucible 807 can be coupled to a vacuum system (not shown). The excess drawn fluid can be removed from the wafer surface by the motor 805 rotating at a low speed rpm. The embodiment of Figure 5 is particularly useful when pre-wetting the surface of the wafer substrate with a high cost pre-wetting fluid, or when a minimum amount of pre-wetting fluid is preferred (e.g., the amount of dissolved gas can be maintained at a low level). After pre-wetting, the wafer is transferred to a standard grab loader for electroplating. A similar design of a pre-wet device with small gaps and a sloping surface is described in the U.S. Patent Application Serial No. 11/200,338, filed on Aug. 9, 2005, which is incorporated herein by reference. The mechanism by which a vacuum is applied.

The chamber shown in Figure 5 can also be used in embodiments where external pressure is applied, as described above. In this embodiment, the chamber and other equipment are designed or modified to withstand and maintain internal positive pressure.

Figure 6 illustrates an embodiment in which pre-wet processing is performed in a plating bath. Alternatively, it can be said that the pre-wet chamber is converted into a pre-wettable wafer substrate and a layer of metal is plated on the pre-wetted wafer substrate. In Figure 6, chamber 901 is a plating bath having a vacuum sealing surface that is part of slot wall 903. The wafer holding portion 905 holds the wafer 915. In the embodiment illustrated in FIG. 6, the plating bath contains an ion resistant, ion permeable high impedance virtual anode (HRVA) 907 and a separate anode chamber (SAC) region 909. An example of a device containing HRVA is described in U.S. Patent Application Serial No. 12/291,356, filed on Nov. 7, 2008, which is incorporated herein by reference. Reference is also made to the U.S. Patent Application Serial No. 11/506,054, filed on Aug. 16, 2006, which is incorporated herein by reference.

Initially, the wafer 915 is held higher than the plating solution 913, and the chamber is evacuated from the vacuum 911. When the chamber is evacuated, the vacuum should be drawn from the back side of the wafer through the wafer holder to avoid wafer breakage. Thereafter, the fluid level 913 is raised to pre-wet the wafer surface. In some embodiments, the fluid is a pre-wet fluid, and in other embodiments, the fluid is a plating solution. Some real In the example, the fluid is degassed prior to contacting the surface of the wafer. Because there is no gas in the chamber, the surface of the wafer faces down, but does not cause any gas-containing bubbles to be trapped under the surface or through the holes. After the pre-wetting is completed, the vacuum is released. Metal plating on wafer 915 can then begin (some embodiments are copper plated). Regardless of whether the wafer is rotated or not, electroplating at normal pressure is generally simpler (in terms of mechanical structure and processing conditions). Alternatively, a vacuum can be maintained throughout the plating process. It is still emphasized that in this and other embodiments, it is preferred to degas the fluid prior to the pre-wet treatment. Otherwise the fluid may release dissolved gases, causing the gas to be trapped in the features or on the surface when the gas is driven out of the liquid.

For a general description of the grapple-loaded electroplating apparatus suitable for use in the embodiments described herein, see U.S. Patent Nos. 6,156,167 and 6,800,187, both incorporated herein by reference.

FIG. 7 illustrates an embodiment of an electroplating system/module 1001 for processing wafers. This tool configuration shows two separate wafer handling robots: the robot 1003 moves a "dry" wafer from the cassette located in the front FOUP (front end open universal container) loader 1005 to the alignment module/transport station (not Illustrated; and transport chamber robot 1004. The alignment module ensures that the wafer is properly aligned with the transfer chamber robot 1004 arm and can be accurately delivered to other chambers/modules of the system. In some embodiments, the alignment module aligns the wafer with an azimuth (so-called "wafer incision alignment") and can also align the vertical and horizontal planes relative to a particular location (ie, x of the fixed wafer) , y, z position system).

After processing and drying are completed, the same or different transfer chamber robots are used to return the wafer from the "pre-wet processing area" at the rear end of the tool to the FOUP. The back end robot (not shown) may contain more than two arms, each having a single or multiple "end actuators" to grasp the wafer. Some "end actuators" hold the bottom of the wafer with a vacuum "stick", while other types only grasp the peripheral edge of the wafer. In some embodiments, a robotic wafer handling arm end effector is only used to treat wafers that are wet on the surface, while others are only used to dispose of the fully dried wafers to minimize contamination.

After the wafer enters the transfer station (including the transfer chamber robot 1004), the wafer is usually sent to the pre-wet chamber 1013 (ie, the pre-wet device is a processing station in the module, and the module further includes plating metal in the crystal. A circular plating station, in some embodiments the metal is copper, various embodiments of the pre-wet chamber are described herein. In some embodiments, system 1001 is used for anodizing. In this embodiment, the module further includes a processing station for performing anodization such as electroetching or electropolishing.

The pre-wet chamber 1013 can be used to pre-wet the wafer in a vacuum, or to apply pressure to the pre-wet wafer, or in some embodiments. As an example, a pre-wet chamber is used to pre-wet the wafer in a vacuum. When the wafer is rotated, the ambient air in the chamber is removed. Once the vacuum is removed, the device side of the wafer is exposed to the degassed pre-wet fluid (degas in the module 1015 in addition to the airflow loop). After the wetting is complete, the excess fluid is removed, the gas is introduced into the chamber to atmospheric pressure, and the chamber is opened to allow the wafer to be removed by a robot or other transport mechanism. In some embodiments, the transport mechanism is configured to transport the pre-wet wafer substrate from the pre-wet station to the plating station in less than about one minute.

In some embodiments, the wafer is then placed into an aligner (not shown), such as a slit aligner. By accurately inserting the edge seal plating bath through the high-precision slit aligner, it becomes possible to exclude the plating solution at the rear and a very small device side edge exclusion region (e.g., about 1 mm from the edge). The plating bath can be specifically designed to have a seal that traverses the slit region. Electroplating and feature filling (i.e., metallization of the metal layer on the wafer substrate) occurs in the plating bath 1021, 1023, or 1025 (i.e., the plating station). In some embodiments, the plating solution is a degassed solution. In some embodiments, the metal is copper. The plating station is used to immerse the wafer in a degassing plating electrolyte in the plating station. In some embodiments, the plating station is used to cathodize the wafer substrate prior to immersing the wafer substrate in the degassing plating electrolyte. The plating solution may be recovered by a separate degassing loop different from the flow loop between the main plating bath and the plating bath, or by passing a degassing element located in the same loop as the pool/plating bath loop. Degas before entering the plating bath.

After the plating is completed, the wafer is rinsed and rotated over the plating bath to remove excess drag fluid, and the wafer holding grab loader is released to release the edge seal so that the wafer can be removed. The wafer is then transferred to a post-processing module for showering and drying.

One problem with pre-wetting is that the wafer surface is "goed after the pre-wet chamber is exposed to the pre-wet fluid in a vacuum in the pre-wet chamber, but before the plating begins). Wetting is possible. Dewetting refers to the phenomenon that the pre-wetting fluid physically unblocks and agglomerates from the surface (ie, is not dry on the surface), leaving a thick layer of pre-wetting fluid in one area of the surface and no pre-wetting fluid in the other area. This phenomenon is generally associated with surfaces that are highly hydrophobic relative to the pre-wetting fluid. If the wetting layer is pulled back or agglomerated from a previously wetted surface, the pre-wet treatment characteristics are lost. To avoid this, a wetting agent can be added to the pre-wet fluid to avoid fluid build-up.

In some embodiments, the operation of the pre-wet chamber or the pre-wet chamber as part of the plating system is controlled by a computer system. The computer includes a controller that contains program instructions. Program instruction Instructions may be included to perform all of the operations required to pre-wet the wafer substrate. In one embodiment, the command is used to reduce the pressure within the processing chamber to subatmospheric pressure and to subsequently contact the wafer substrate with the pre-wetting fluid at sub-atmospheric pressure to form a wetting layer on the surface of the substrate. During delivery of the liquid pre-wet fluid to the wafer substrate at sub-atmospheric pressure, the wafer substrate can be rotated at a first rate of rotation for a period of about 10 to 120 seconds. Next, the delivery of the pre-wet fluid is stopped. After the delivery of the pre-wet fluid is stopped, the wafer substrate is rotated at a second rate of rotation to remove excess surface from the wafer substrate to draw the pre-wetting fluid. In certain embodiments, the vacuum within the processing chamber is released after the pre-wet fluid delivery is stopped, and before excess excess pre-wetting fluid is removed. In an alternative embodiment, the vacuum is released after removal of the excess drawn pre-wetting fluid. In various embodiments, the wafers can be rotated at different rates. In some embodiments, the first rate of rotation during transport of the liquid pre-wet fluid onto the wafer substrate is less than about 300 rpm, and the second rate of rotation to remove excess pre-wetting fluid from the wafer substrate is at least about 300 rpm. In other embodiments, the first rate of rotation is about 100 rpm or less and the second rate of rotation is at least about 500 rpm. In still other embodiments, the pre-wet device removes excess pre-wet from the wafer substrate by a method selected from the group consisting of centrifugal rotation, air-knife drying, and wiping. Fluid, and the controller includes program instructions to perform these operations.

Process/Method In the general pre-wet method of certain embodiments disclosed herein, a vacuum is first created in the environment surrounding the wafer. The wafer surface is then sprayed, flooded, covered or impregnated with a sufficient amount of pre-wetting fluid (and in some embodiments degassing), eventually exposing the entire wafer to a sufficient and thick liquid layer. This layer does not necessarily cover the entire surface at any time until the latter stage of processing. The surface of the wafer is then impregnated or otherwise exposed to the pre-wet fluid layer (eg, continuously spraying, overflowing, covering or impregnating the surface with additional fluid) for a period of time until any pre-wet fluid composition on the surface of the wafer The adsorption (or reaction) is substantially completed or equilibrium is achieved and the desired or uniform wetting characteristics (hydrophilic, low contact angle) are achieved. After pre-wetting, the spraying, overflowing or covering of the wafer with the pre-wet fluid is stopped. In some embodiments, the vacuum is released and the excess drag fluid is removed from the (current) fully hydrophilic surface (eg, by centrifugation, air knife drying, squeegee wiping, etc.) to leave a uniform, adherent pre-wet on the surface. A thin layer of fluid. In other embodiments, the excess drag fluid is removed prior to releasing the vacuum. Finally, the wafer is transferred to a plating bath to plate the wafer.

Because between the removal of excess pre-wetting fluid from the wafer surface and the initiation of metal deposition, it may last for any length of time between a few seconds and more than one minute, making the wafer whole hydrophilic and completely immersed in all surfaces. Covering is very important. In the following time, The hydrophobic surface/fluid combination causes the fluid to flow back from the wafer surface, starting at the edge of the wafer, thereby freeing up part of the wafer surface. Dewetting may cause fluid to be drawn from any of the recess features in the wafer substrate, which may result in bubbles trapped in the features entering the plating bath during immersion. Hydrophobic surfaces, particularly those that have been completely dewet in certain areas, have a non-uniform thickness of the fluid pre-wetting layer on the wafer substrate. In the case where the composition of the pre-wetting fluid used is different from that of the plating bath, the pre-wet wafer is subsequently placed in the immersion of the plating solution, and if the pre-wetting fluid does not properly wet the wafer, uniform wetting cannot be produced. s surface. Non-uniform wetting of the wafer causes the diffusion time and the concentration of each component to vary across the wafer due to the thickness of the wetting layer. This can result in variations in feature fill conditions or various wafer surface defects such as trapping bubble formation, metal potholes, metal thickness variations, or protrusions. Therefore, after the pre-wetting treatment, the pre-wetting fluid should produce a uniform, small contact angle with respect to the entire wafer surface, and if possible, a contact angle of about 45 degrees or less. When it is possible to produce a smaller contact angle, a very thin, adherent layer of pre-wetting fluid can be produced.

It is often observed that the contact angle of a surface changes over time and that when the hydrophobic surface is exposed to a particular liquid, it becomes more hydrophilic over time. Certain wafer surfaces, such as those covered by plasma vapor deposition, can exhibit substantial reduction in liquid/surface contact angle over time, with continued exposure of the surface to the pre-wet fluid. In particular, continuous exposure of such surfaces under vacuum conditions results in a rapid and complete change in the surface, i.e., from a general dewetting, hydrophobic state to a wet, hydrophilic state.

By applying the removal of the pre-wetting fluid to the surface while maintaining the low pressure/vacuum environment, the trouble of simultaneously expanding, flushing or removing the trapped bubbles from the surface can be substantially eliminated, so that the previous exposure is not exposed. Or limited exposure to the pre-wetting fluid creates the trouble of exposing the wafer that still has a hydrophobic region. Considering the combination of vacuum and wetting, the various areas of the wafer surface fall into five types of wetting: 1) hydrophobic wetting: covered with a pre-wet fluid and wetted, but not enough time to keep it Hydrophobic; 2) Hydrophilic wetting: covered with a pre-wet fluid and wetted for a sufficient time, so it becomes hydrophilic; 3) non-wetting: hydrophobic, exposed to air, never exposed to pre-wet fluid; 4) Dewetting: previously wetted, but dewetting, and exposed to air again; 5) trapping bubbles: there are bubbles on the surface, the bubbles are under the pre-wetting fluid layer, and the bubbles contain trapped air.

It should be noted that the zone having states 3, 4, 5 does not have any adsorption or chemical reaction, so that there will be no hydrophobic to hydrophilic surface transition unless the zone is subsequently wetted and prior to wetting. Furthermore, the area of state 1 or 2 around state 1 will wet, or It will become hydrophilic, allowing the fluid to flow freely and continuously over this surface, which also makes it more difficult to remove the bubbles or wet the adjacent areas. In addition, areas that have previously been exposed to pre-wet fluids, which are currently hydrophobic surfaces, may alternately enter into a liquid-free, covered, and hydrophobic state. The process continuously transitions between these states as the fluid drains adjacent to the hydrophilic region, back and forth between state 1 and state 3 multiple times until finally i) transitions to state 2 to become hydrophilic and wet, Thereafter, it remains in state 2; or ii) is surrounded by a more wetted region, trapping bubbles, and transitioning to state 4.

The above treatment under atmospheric conditions (i.e., in air) should be compared to the treatment carried out in a vacuum (and the dehumidified fluid is degassed). Of these treatments, there are only three types that have been wetted: 1) wetted: covered with pre-wet fluid and wetted; 2) unwetted: exposed to vacuum, never exposed to pre-wet fluid; 3) go Wetting: previously wetted, but de-wetting and re-exposure to vacuum.

As long as a particular portion of the wafer is exposed to the pre-wetting fluid (state 1) and for a sufficient amount of time, the pre-wetting process performed in vacuum ensures that that particular portion of the wafer will eventually become hydrophilic. Unlike pre-wet processing at atmospheric pressure, there is no need for a high flow rate pre-wetting fluid stream to "flush away" trapped bubbles. Furthermore, bubble washout is not 100% effective and often causes bubble splitting, leaving a large number of smaller, more difficult to remove bubbles. Therefore, pre-wetting in a vacuum is a more reliable treatment in which the defect is greatly reduced as compared with spraying, covering or dipping the wafer to the pre-wet fluid only under normal pressure. Pre-wet treatment in a vacuum is preferred. Other factors include a) different surface energies at the vacuum/liquid/metal interface, contact angles are generally lower than air/liquid/metal interfaces; b) metal oxides are avoided/ The formation of nitride/carbonate; and c) the use of a degassing fluid eliminates the possibility of gas condensation from the fluid due to abnormal temperature or pressure changes at certain points of the interface between the liquid and the wafer.

Figure 8a is a flow diagram of a general embodiment of a pre-wet process (1100). A wafer substrate having an exposed metal layer on at least a portion of its surface is provided in the pre-wetting processing chamber (1105). The wafer substrate is then contacted with the pre-wetting fluid at sub-atmospheric pressure to form a wetting layer on the wafer substrate surface (1115). This pre-wetting treatment can be carried out in the pre-wet equipment described herein.

There are different wafer substrates in different embodiments. The wafer substrate can have at least one recess feature. The recess feature can be a damascene feature formed by a damascene patterning process. In the damascene plating process, the recess formed by the damascene patterning process in the dielectric layer of the semiconductor wafer is filled with a metal film. The recess features may be features that pass through the mask.

In certain embodiments, the pre-wetting fluid is substantially free of dissolved bubbles. In some embodiments, one or more dissolved gases in the pre-wetting fluid are removed prior to contacting the wafer with the pre-wetting fluid. To assist in the removal of dissolved gases, in certain embodiments, the pre-wet fluid is cooled to less than about 20 degrees C during gas removal. In some cases, in order to obtain a pre-wet fluid that is substantially free of dissolved gases, the pre-wet fluid treatment tank allows the pre-wet fluid to pass through the wafer prior to contacting the wafer substrate with the pre-wetting fluid. The gas loop is circulated for a specific period of time (depending on the capacity and capacity of the degassing gas, usually half an hour). This description is described herein with reference to FIG. Usually this means that the fluid flow passes through the loop when the vacuum pump is started and in the vacuum, and the valve that connects the degasser to the pre-wet tank and the pump is open. This ensures that the pre-wet fluid that is subsequently supplied to the wafer surface is substantially free of dissolved gases. Measurements of the system so designed show that the residual dissolved oxygen can be as low as about 1 to 2%, or below the saturation caused by oxygen in the air.

Further, the top of the chamber of the processing chamber and the wall heater can be turned on, the temperature is set to about 10 degrees C, and some conditions can be about 20 degrees C or higher than the temperature of the pre-wetting fluid. For example, if the fluid temperature is about 20 degrees C, the proper temperature of the wall is about 40 to 50 degrees C. The top of the chamber and the wall heater avoid surface condensation and also avoid the possibility of liquid droplets falling on the exposed surface before vacuum pre-wetting. The work of clearing the surface of the chamber can be accomplished by closing the door to bring the chamber into a vacuum and heating the wall to the target temperature. For example, in the absence of wafers present in the chamber and wall heating, the chamber is evacuated and held under vacuum for about 10 minutes or more to remove any liquid that may accumulate in the ceiling of the chamber or the upper portion of the chamber wall. The vacuum can be removed by backfilling with clean, dry nitrogen. This step removes any possible condensation on the walls of the chamber and minimizes the formation of gas-generating particles. After confirming that a) all chamber fluid level sensors are at appropriate values (if the tank is full, the chamber is empty), b) the heater is turned on, c) the vacuum is ready for processing, it can be turned on The pre-wet chamber handles the door and removes the guard of the door (if provided). Next, the wafer is placed in the chuck, the robot arm is retracted, the vacuum door is closed, the liquid splash guard is raised (if provided), or the wafer is lowered below the guard.

In some embodiments, the vacuum target value for the pre-wet treatment is between about 10 and 100 torr, such as about 40 torr. In some embodiments, the vacuum (i.e., sub-atmospheric pressure) is about 50 torr. In some embodiments, the vacuum line can be closed after vacuuming is completed, while in other embodiments, the pump continues to draw vacuum as the pre-wetting fluid is injected into the chamber and reaches the wafer.

In some embodiments, the liquid pre-wet fluid is delivered to the surface of the wafer substrate. This can include immersing the wafer substrate in a pre-wetting fluid. Alternatively, this may include spraying or overcoating with a pre-wet fluid Cover the wafer substrate. In other embodiments, the wafer substrate is brought into contact with the pre-wet fluid by transporting the gaseous pre-wet fluid onto the wafer substrate. The gaseous fluid can condense to form a wetting layer on the wafer substrate. In these embodiments, the temperature of the wafer substrate can be reduced below the pre-wetting fluid condensation temperature prior to exposing the wafer substrate to the pre-wetting fluid.

In some embodiments, the wafer can be rotated while the liquid pre-wetting fluid is being transported onto the surface of the wafer substrate. In some embodiments, the wafer substrate can be rotated at a rate between about 10 rpm and 300 rpm. In still further embodiments, the wafer substrate can be rotated at a rate between about 10 rpm and 100 rpm. In other embodiments, the wafer substrate is rotated at a speed of from about 100 rpm to 400 rpm, such as about 300 rpm. In the case of high speed (such as about 400 to 800 rpm), or the speed cycle, the wafer is periodically accelerated and decelerated, which can be used for a short time (about 2 to 10 seconds) to overcome the fluid of highly hydrophobic wafers. Wetting group resistance is a problem. The chamber evacuation can be initiated before or after the wafer spin begins.

In embodiments where a liquid pre-wet fluid is used, the flow of the pre-wetting fluid is initiated into the chamber and onto the surface of the wafer. Use a flow rate typically between about 0.5 and 2 lpm, such as 0.8 lpm, for about 3 seconds to 1 minute, such as about 20 seconds, depending on the time necessary to achieve complete wetting of a particular surface, wafer speed, fluid wetting. Depends on the property. In some embodiments, the pre-wetting fluid contacts the wafer substrate from about 10 seconds to 120 seconds. After the wetting treatment is completed, the pre-wet fluid flow is stopped, such as by closing the pre-wet fluid flow valve.

The chamber then returns to atmospheric pressure. In some embodiments, the chamber is returned to atmospheric pressure with an oxygen-free gas such as dry nitrogen.

In some embodiments, excess pre-wetting fluid on the surface of the substrate is removed. This can be done before or after the chamber returns to atmospheric pressure. In some embodiments, the excess pre-wetting fluid is removed from the surface of the wafer substrate using a rotating wafer substrate. The rate of rotation of the wafer substrate is increased to a value at which excess trace fluid can be removed from the surface of the wafer substrate, but a thin layer of liquid remains. The wafer substrate rotation speed may be from about 300 rpm to 1000 rpm during removal of excess pre-wet fluid. The wafer substrate can be rotated for less than about 20 seconds during removal of excess pre-wetting fluid. In other embodiments, the wafer substrate rotation speed is increased between about 5 and 60 seconds to between about 250 and 800 rpm while avoiding complete drying of the pre-wetting fluid. Although the spin process can typically be initiated prior to releasing the vacuum, wafer drying may be reduced by performing this step after the vacuum is released, as evaporation of the thin layer may be less likely to result in a dry surface at some point on the wafer.

After removing the excess drag fluid on the surface of the wafer substrate, stopping the rotation of the wafer substrate, lowering the splash mask and/or raising the wafer substrate (if so installed), opening the vacuum gate, and pulling the wafer from the cavity The chamber is removed and placed in the plating chamber. In some embodiments, the pre-wet wafer substrate is exposed to the chamber and the environment outside the plating chamber for less than one minute. In other embodiments, the pre-wet wafer has a wetting layer having a thickness of between about 50 and 500 microns when transported to the plating chamber, and just prior to electroplating. After the wafer substrate enters the plating chamber, in some embodiments, the wafer substrate is plated with a degassing plating solution. In some embodiments, the pre-wet wafer substrate is cathodized relative to the plating solution prior to contacting the wafer substrate with the plating solution. The pre-wetting chamber and the plating chamber can be separate chambers in the same device module. In other embodiments, the wafer substrate is plated in the same chamber that was previously used for pre-wetting. In these embodiments, electroplating can be performed using a degassing plating solution.

In an alternative embodiment, after removing the pre-wet wafer substrate from the pre-wet processing chamber, the pre-wet wafer substrate is transferred to a chamber for performing anodization such as electro-etching and electro-polishing.

Figure 8b is a flow diagram of another embodiment of a pre-wet process (1150). A wafer substrate having an exposed metal layer on at least a portion of its surface is provided within the pre-wetting processing chamber (1155). The pressure in the processing chamber is then reduced to sub-atmospheric pressure (1160). The wafer substrate is then contacted to the pre-wet fluid (1165) at sub-atmospheric pressure. The pressure within the processing chamber is then increased to promote bubble removal (1170). This pre-wetting treatment can be carried out using the pre-wet device design described herein.

The device design and method described herein can be used to pre-wet a partially fabricated semiconductor device structure. In some embodiments, the pre-wet partially fabricated semiconductor device structure includes at least one recess feature. The recess feature has a layer of metal to line the features. The recess feature also includes a substantially airless pre-wetting fluid to fill the feature, the pre-wet fluid comprising an aqueous metal salt solution that does not substantially illuminate the accelerator and balance agent.

As described above, different combinations of pre-wetting fluid composition and plating solution composition can be used for the pre-wet treatment in combination with the plating treatment. 9 is a flow diagram of an embodiment of a plating process 1200 of electroplating a copper layer on a wafer substrate. A wafer substrate (1205) having an exposed metal layer on at least a portion of its surface is provided within the pre-wet processing chamber. The wafer is then contacted with a pre-wetting fluid to form a pre-wet fluid layer on the wafer substrate (1210). The pre-wet wafer is then contacted with a plating solution comprising metal ions to electroplate the metal layer on the wafer substrate (1215).

The device design and method described herein are applicable to other liquid semiconductor processes and conditions other than plating/feature filling, as long as there are bubbles in the large aspect ratio feature or Collecting gases can cause problems.

All of the operations described herein, including various wetting, pre-wetting, degassing, aligning, transporting, and plating operations, can be programmed or set in a controller that is placed or connected to the module and system. The combination or sequence of any of the operations described herein can be used to encode programs or settings. Firmware, software macros, application specific integrated circuits, shared software, machine readable media, and the like can be used to implement controller instructions and can be coupled to one or more controllers. Furthermore, one or more controllers can include one or more memories and one or more processors for executing instructions to enable the device to perform the methods in accordance with the embodiments disclosed herein.

Through the photoresist plating pre-wetting device and processing examples, the foregoing device design and method can also be used for through-resistive plating treatment (ie, plating on a wafer substrate including photoresist). During the through-resistance plating, metal pillars or lines are formed on the wafer substrate, and the photoresist is used as a plating template material. For example, in the through-resistance plating process, a metal seed layer is formed on the surface of the wafer substrate. The seed layer is then coated with a photoresist, and the photoresist is exposed to ultraviolet light, and part of the photoresist is removed during development processing (for example, when the photoresist is exposed, the portion exposed to the light is removed, and the negative photoresist is not exposed. A portion of the light is removed) to form features in the photoresist. In some embodiments, the aspect ratio of the features can be from about 2 to 1 to about 1 to 2, or about 1 to 1. In some embodiments, the features of the features in the photoresist have an opening size of from about 5 microns to 50 microns, from about 10 microns to 100 microns, or from about 20 microns to 50 microns. In some embodiments, lines or paths (eg, used to form redistribution layers) may be formed in the photoresist.

The descum treatment involves exposing the wafer substrate to an oxygen plasma, and this process can be performed to remove any residual photoresist of the metal seed layer in the features. The metal is then electroplated onto the metal seed layer in the features. In some embodiments, the metal can be plated to a thickness close to the thickness of the photoresist. For example, the plating metal thickness can be slightly thicker or thinner than the photoresist thickness. After plating the metal, the photoresist of the wafer substrate is stripped.

In some embodiments, a pre-wet treatment may be performed prior to the electroplating process. In one example, there is a wafer level package in which a wafer substrate can contact a pre-wet fluid and a thin layer of nickel having a thickness of about 2 microns to 4 microns is applied to the metal seed layer. A solder alloy such as SnAg, Sn or SnCu can be plated onto the thin layer of nickel. The photoresist remaining on the wafer substrate is then removed. The metal seed layer remaining on the surface of the wafer substrate (ie, the metal seed layer that is not plated on the top) can also be removed. The pre-wet device and chamber (see FIGS. 1-6) can be used to form a pre-wet layer on a wafer substrate through which photoresist is to be plated.

However, at some point, photoresist particles or residues are formed which stagnate on the metal seed layer formed on the features of the photoresist. This may be the residual material of the development step or the particles produced during the slag removal step. The photoresist particles/residue on the seed layer can then be electroplated to form defects in the plated metal. The photoresist particles can be from about 2 microns to 7 microns in size, or about 5 microns in size. The photoresist particles/residue may have a size that is a fraction of the size of the photoresist feature (eg, the photoresist particles may be about 10% of the feature size). The photoresist particles can be formed during the slag removal process (as caused by physical damage to the photoresist during the slag removal process) and may adhere to the walls of the photoresist features. Pre-wetting treatment may transfer photoresist particles/residues to the metal seed layer.

In certain embodiments, the pre-wetting chamber can include an element that delivers a pre-wet fluid that is subjected to a pressure that causes the pre-wet fluid to have sufficient velocity to remove the particle attachment (ie, the photoresist surface or metal) Photoresist layer) of photoresist particles / residue. In a particular embodiment, the pre-wetting fluid has a velocity component that is both parallel and perpendicular to the surface of the wafer substrate. This one or two components provide sufficient force to overcome the forces (such as electrostatic forces and/or friction) that hold the photoresist particles on the wafer substrate. In addition to loosening the photoresist particles, the flow of the pre-wet fluid to the pre-wet chamber causes the loose photoresist particles to be carried away from the surface of the wafer substrate. Removal of photoresist particles/residues can be enhanced with higher flow pre-wetting fluids. Because the wafer substrate typically includes a plurality of features in the photoresist, when the photoresist particles are removed from the features and transported out of the wafer substrate, the particles must be prevented from falling into different features and trapped.

Figures 10a and 10b illustrate a pre-wet chamber embodiment through photoresist plating. Figure 10a is a cross-sectional view of the pre-wet chamber, and Figure 10b is a perspective cross-sectional view of the interior of the pre-wet chamber. The pre-wet chamber 1350 includes a chamber body 1352 and a chamber cover 1354 that form a vacuum seal when in contact. The chamber body 1352 supports a wafer substrate holding portion 1356 for holding the wafer substrate 1358 and for rotating the wafer substrate 1358.

The chamber body 1352 further includes a vacuum weir 1360 and a fluid inlet portion 1362. Vacuum crucible 1360 is coupled to the vacuum pump and is used to create sub-atmospheric pressure in pre-wet chamber 1350. Fluid inlet portion 1362 is coupled to a degasser (not shown). A degasser is used to remove one or more dissolved gases from the pre-wetting fluid to produce a degassed pre-wet fluid. The fluid inlet portion is configured to deliver the degassed pre-wet fluid to the wafer substrate at a velocity of at least about 16 meters per second (m/s) to release the photoresist particles from the surface of the wafer substrate. Furthermore, the fluid inlet portion is configured to transport the degassed pre-wetting fluid to the wafer substrate at a flow rate of at least about 0.6 liters per minute (L/min), so that the loose photoresist particles are washed away from the wafer substrate. except.

In the illustrated embodiment, the fluid inlet portion 1362 includes a nozzle 1364 that is mounted to the sidewall of the chamber body 1352. In some embodiments, the nozzle 1364 is a fan nozzle. The fan nozzle can be used to transport the degassed pre-wet fluid onto the wafer substrate, causing the degassed pre-wetting fluid to strike the wafer substrate in a linear shape. Figures 10a and 10b show the free flow lines of the degassed pre-wet fluid 1366 from the nozzle 1364 to the impact wafer substrate 1358.

The type of fluid nozzle of the fan nozzle is such that the fluid flow is dispersed from the nozzle in a fan shape. For example, a fan nozzle having a spray angle of about 10 to 120 degrees or, in a particular embodiment, about 95 degrees can be used as the nozzle 1364. The spray angle is the angle of the fan-like fluid produced by the fan nozzle. In a particular embodiment, the fan nozzle for the pre-wet chamber 1350 can have an opening size of 0.04 吋 to 0.06 吋, or about 0.05 吋, a flow rate of about 0.6 L/min to 2.2 L/min, or about 1.3. L/min, nozzle pressure is about 30 pounds per square inch (psi) to 80 psi, or about 40 psi, and the flow rate at the wafer surface is about 16 m/s to 31 m/s.

In a pre-wet operation using the pre-wet chamber 1350, the pressure in the pre-wet chamber may be reduced to sub-atmospheric pressure before the wetting layer is formed on the wafer substrate. For example, in some embodiments, forming a wetting layer on the wafer substrate can begin when the pressure of the pre-wetting chamber drops below about 50 Torr. The wafer substrate can be rotated at a first rotational speed prior to forming the wetting layer and forming the wetting layer. Next, the wetting layer is formed on the wafer substrate in the sub-atmospheric pre-wetting chamber by contacting the wafer substrate with the degassed pre-wetting fluid from the deaerator and entering through the fluid inlet portion. In some embodiments, the wafer substrate can be in contact with the degassed pre-wetting fluid for about 10 seconds to 120 seconds.

After the wetting layer is formed on the wafer substrate, the delivery of the degassed pre-wet fluid can be stopped. After the degassing of the pre-wetting fluid is stopped, the pressure of the pre-wet chamber can be increased to atmospheric pressure or increased beyond atmospheric pressure. Next, the wafer substrate can be rotated at a second rotational speed to remove more than the surface of the wafer substrate from the degassed pre-wetting fluid. In some embodiments, all of the foregoing processing operations can be performed in a pre-wet process. In some other embodiments, some of the foregoing processing operations may be excluded from the pre-wetting process.

Rotating the wafer substrate at the first rotational speed during the pre-wet processing can help remove the photoresist particles of the wafer substrate. For example, the centripetal force applied to the photoresist particles can help transport the release photoresist particles to the edge of the wafer substrate and feed the wafer substrate. However, the centripetal force applied to the photoresist particles near the center of the wafer substrate may not be too high. Thus, in some embodiments, the pre-wetting fluid is transported as a line through the center of the wafer substrate (eg, near the axis of the wafer substrate) to impact the wafer substrate to assist in removing photoresist particles in the middle of the wafer substrate.

For example, in a pre-wet operation using a pre-wet chamber 1350, the wafer substrate can be placed into a pre-wet chamber to close the chamber. A vacuum of about 50 Torr to 100 Torr or about 70 Torr may be formed in the pre-wet chamber. The wafer substrate may be rotated at a first rotational speed of about 20 rpm to 800 rpm or about 80 rpm, while the wafer substrate contacts the degassed pre-wet fluid for about 5 seconds to 90 seconds or about 10 seconds, and the flow rate may be from 0.6 L/min to 2.2 L/min. Or about 1.3 L/min, the fluid velocity on the wafer surface is about 16 m/s to 31 m/s. The wafer substrate can then be rotated at a second rotational speed of about 20 rpm to 800 rpm or about 25 rpm, while the wafer substrate contacts the degassed pre-wet fluid for about 1 second to 90 seconds or about 20 seconds, and the flow rate is about 0.6 L/min to 2.2 L/min. Or about 1.3 L/min, the fluid velocity on the wafer surface is about 16 m/s to 31 m/s. In some embodiments, this second rotational speed operation may not be included in the pre-wet operation. The pre-wet chamber can then be adjusted to atmospheric pressure, after which the wafer substrate can be rotated from 1 rpm to 250 rpm or about 180 rpm. In some embodiments, the wafer substrate does not have to be rotated after the pre-wet chamber is adjusted to atmospheric pressure.

In some embodiments, the pre-wetting fluid can be delivered to the wafer substrate in a pulsed manner. For example, the pre-wetting fluid can be activated for about 1 second to 9 seconds or about 5 seconds, and then stopped for 100 milliseconds to 900 milliseconds or about 500 milliseconds. The pulse of the pre-wet fluid in certain embodiments may be repeated about 5 to 15 times or about 10 times.

In certain embodiments, deionized water can be used for pre-wetting treatment through photoresist plating. In certain other embodiments, a chemical solution that assists in releasing the photoresist substrate from the wafer substrate and removing the photoresist particles can be used for pre-wetting processing through the photoresist plating.

Figures 11a and 11b illustrate a pre-wet chamber embodiment for through-resistive plating. 11a is a cross-sectional view of the pre-wet chamber, and FIG. 11b is a top view of the fluid inlet manifold and the wafer substrate. The pre-wet chamber 1400 includes a chamber body 1402 in the chamber cover 1404 that, when contacted with each other, forms a vacuum seal. The cavity body 1402 supports the wafer substrate holding portion 1406 for holding the wafer substrate 1408 and rotating the wafer substrate 1408. The chamber body 1402 further includes a vacuum crucible 1410. A vacuum crucible is coupled to the vacuum pump and is used to form sub-atmospheric pressure in the pre-wet chamber 1400.

The chamber cover 1404 includes three fluid inlet portions 1412 that are coupled to the manifold 1416. Manifold 1416 can include one or more turns. As shown, the manifold 1416 includes a bore 1418 that can be coupled to a degasser (not shown) to introduce the pre-wet fluid into the pre-wet chamber 1400. The crucible 1420 of the manifold 1416 can be used to purge the manifold 1416 with an inert gas to remove any pre-wetting fluid that may remain within the manifold 1416 after the pre-wet treatment.

In a particular embodiment, each fluid inlet portion 1412 is used to degas the pre-wet fluid A speed of at least about 7 m/s is delivered to the wafer substrate to release the photoresist particles on the wafer substrate. Furthermore, in a particular embodiment, all of the fluid inlets are used to deliver the degassed pre-wet fluid to the wafer substrate at a flow rate of at least about 0.4 L/min, so that the loose photoresist particles are washed away from the wafer substrate. And removed.

In some embodiments, each fluid inlet portion 1412 includes a nozzle 1414. In some embodiments, each nozzle 1414 is a fan nozzle. The fan nozzle can transport the degassed pre-wetting fluid onto the wafer substrate, causing the degassed pre-wet fluid to strike the wafer substrate in a linear or rectangular shape. FIG. 11a illustrates the degassed pre-wet fluid 1422 striking the wafer substrate 1408 from the nozzle 1414. As also shown in Figure 11a, the nozzles 1414 are configured such that the degassed pre-wet fluid nozzles are substantially dispersed in the radius of the wafer substrate, i.e., from the edge of the wafer substrate to the center of the wafer substrate. With this setting, the degassed pre-wet fluid also contacts the wafer substrate over substantially the entire radius of the wafer. Due to the rotation of the wafer substrate, the entire wafer substrate surface is in contact with the pre-wetting fluid after the primary wafer substrate is completely rotated.

As mentioned, the fluid nozzle type of the fan nozzle is such that the fluid flow is fanned out from the nozzle into a fan shape. In a particular example, regarding pre-wetting a 300 mm diameter wafer substrate in a pre-wet chamber 1400, the pre-wet chamber can include three fan-shaped nozzles. Each fan nozzle can have a spray angle of about 20 to 60 degrees or about 40 degrees. Each of the fan nozzles for the pre-wet chamber 1400 can have an opening size of 0.02 吋 to 0.05 吋 or about 0.035 ,, a flow rate of about 0.15 L/min to 1 L/min, or about 0.25 L/min, and a nozzle pressure of about 30 psi. At 80 psi, or about 40 psi, the fluid flow rate on the wafer surface is about 7 m/s to 31 m/s. Three nozzles, each having a flow rate of about 0.25 L/min, can deliver a pre-wet fluid at a total flow rate of about 0.75 L/min. In some embodiments, the fan shape of the pre-wet fluid delivered from the nozzle is substantially flat.

In a pre-wet operation using the pre-wet chamber 1400, the wafer substrate can be placed in a pre-wet chamber to close the chamber. The vacuum that can be formed in the pre-wet chamber is about 50 Torr to 100 Torr, or about 70 Torr. The wafer substrate can be rotated at a first rotational speed of about 20 rpm to 800 rpm or about 80 rpm, while the wafer substrate contacts the degassed pre-wet fluid from about 5 seconds to 90 seconds, or about 10 seconds, and the total flow rate is about 0.45 L/min to 3 L/ In minutes, or about 0.75 L/min, the fluid flow rate on the wafer surface is about 7 m/s to 31 m/s. The wafer substrate can then be rotated at a second rotational speed of about 20 rpm to 800 rpm or about 25 rpm, while the wafer substrate contacts the degassed pre-wet fluid from about 1 second to 90 seconds, or about 20 seconds, with a total flow rate of about 0.45 L/min to 3 L/ In minutes, or about 0.75 L/min, the fluid flow rate on the wafer surface is about 7 m/s to 31 m/s. In some embodiments, this second rotational operation is not included in the pre-wet operation. Pre-wet The chamber can then be adjusted to atmospheric pressure, after which the wafer substrate is rotated at 1 rpm to 250 rpm or about 180 rpm. In some embodiments, the wafer substrate does not rotate after the pre-wet chamber is adjusted to atmospheric pressure.

In some embodiments, the pre-wetting fluid can be delivered to the wafer substrate in a pulsed manner. For example, the pre-wetting fluid can be delivered for about 1 second to 9 seconds, or about 5 seconds, and then not delivered for 100 milliseconds to 900 milliseconds, or about 500 milliseconds. In certain embodiments, the pulse of the pre-wetting fluid can be repeated about 5 to 15 times, or about 10 times.

Figure 12 illustrates an embodiment of a pre-wet chamber for through-resistive plating. The pre-wet chamber 150O can be similar to the pre-wet chamber 1400 except for one point: the pre-wet chamber 1500 can include more fluid inlets. Furthermore, the degassed pre-wet fluid impinges on the wafer substrate over the diameter of the wafer substrate within the pre-wet chamber 1500.

The pre-wet chamber 1500 includes a chamber body 1502, a chamber cover 1504, which creates a vacuum seal when in contact. The chamber body 1502 includes a wafer substrate holding portion 1506 for holding the wafer substrate 1508 and the rotating wafer substrate 1508. The chamber body 1502 further includes a vacuum crucible 1510. A vacuum crucible is coupled to the vacuum pump and a sub-atmospheric pressure is formed in the pre-wet chamber 1500.

The chamber cover 1504 includes five fluid inlet portions that are coupled to the manifold 1516. Manifold 1516 can include one or more turns. As shown, the manifold 1516 includes a bore 1518 that can be coupled to a degasser (not shown) for introducing a pre-wet fluid to the pre-wet chamber 1500. The crucible 1520 of the manifold 1516 can be used to purge the manifold 1516 with an inert gas to remove any remaining pre-wetting fluid after the pre-wet treatment.

Each fluid inlet portion 1512 is configured to deliver a degassed pre-wet fluid to the wafer substrate with sufficient velocity to release the photoresist particles from the surface of the wafer substrate. All of the fluid inlets are used to deliver the degassed pre-wet fluid to the wafer substrate at a flow rate such that the loose photoresist particles are removed from the wafer substrate for removal.

As with the embodiment described above, each fluid inlet portion 1512 can include a nozzle 1514. Further, as described above, each of the nozzles 1514 may be a fan-shaped nozzle. 12 illustrates the degassed pre-wet fluid 1522 striking the wafer substrate 1508 from the nozzles 1514. In the pre-wet chamber 1500, the nozzle 1514 is set such that the degassed pre-wetting fluid contacts the wafer substrate over substantially the entire diameter of the wafer substrate, ie, from one edge of the wafer substrate through the center of the wafer substrate to the crystal The other edge of the circular substrate. As the wafer substrate rotates, the entire wafer substrate surface contacts the pre-wetting fluid after one half of the wafer substrate has rotated a full turn.

In some embodiments, the pre-wet chamber 1500 of FIG. 12 will be more capable of removing photoresist particles from the wafer substrate than the pre-wet chamber 1400 of FIG. 11a. For example, when the photoresist particles move in the wafer substrate features (if the force holding the photoresist particles is overcome) but there is no removal from the features, the wafer substrate needs to be completely rotated in the pre-wet chamber 1400. The degassed pre-wet fluid removes the photoresist particles from the features. In the example of the pre-wet chamber 1500, the photoresist particles are removed from the features by the degassed pre-wetting fluid, requiring only a half turn of the wafer substrate.

In some embodiments of the pre-wet chambers 1400, 1500 shown in Figures 11a and 12, the chamber cover may remain stationary and the loading/unloading of the wafer substrate from the pre-wet chamber may be substantially vertically movable from the chamber body. To execute. Keeping the chamber cover stationary helps to prevent droplets of pre-wetting fluid from falling onto the wafer substrate when the wafer substrate is loaded into the pre-wet chamber. When the wafer substrate is not in a vacuum and a drop of pre-wetting fluid contacts the wafer substrate, air bubbles may be trapped between the wafer substrate and the pre-wetting fluid droplets. The helium of the manifold of the pre-wet chamber can be used to purge the manifold prior to loading the wafer substrate into the pre-wet chamber. This can also help to prevent droplets of pre-wetting fluid from falling onto the wafer substrate.

The velocity and force of the pre-wetting fluid contacting the wafer substrate in the pre-wet chambers 1400, 1500 shown in Figures 11a and 12, as compared to the pre-wet chamber 1350 shown in Figure 10a, typically have a large vertical Parallel component ratio (from the viewpoint of the wafer surface). For example, in the pre-wet chambers 1400, 1500, the fluid impact angle of the pre-wet fluid relative to the plane of the substrate surface is about 90 degrees, ranging from about 60 degrees to 90 degrees. The angle of incidence of the pre-wet fluid within the pre-wet chamber 1350 is about 6 degrees, ranging from about 3 to 10 degrees. Although the photoresist particles are both perpendicular and parallel to the wafer substrate to release the photoresist particles and remove them from the wafer substrate, the photoresist is perpendicular to the surface of the wafer substrate at a high speed. Thus, the pre-wet fluid velocity in the pre-wet chambers 1400, 1500 having a velocity component that is primarily perpendicular to the wafer substrate may be eliminated from the pre-wet chamber 1350 (having a vertical and parallel velocity component parallel to the wafer substrate). height of.

Although the pre-wetting chamber 1400 is illustrated as including three fluid inlet portions and three nozzles, and the pre-wetting chamber 1500 is illustrated as including five fluid inlet portions and five nozzles, the pre-wetting chamber may include one to eight ( In some embodiments there are more) fluid inlets and corresponding nozzles. Again, the pre-wet treatment using the pre-wet chamber 1400 or the pre-wet chamber 1500 can be similar to the pre-wet treatment using the pre-wet chamber 1350, as described above. Furthermore, although fan-shaped nozzles are described in the embodiments of pre-wet chambers 1350, 1400, 1500, nozzles capable of producing a conical fluid flow or other shaped fluid flow can also be used.

In some embodiments, performing on a wafer substrate for through-resistive plating Prior to pre-wetting, the wafer substrate can first pass through an ionizer bar in the ionization system to assist in removing the just-group particles from the wafer substrate. This ionization system operates by increasing the conductivity of the air with ionized gas molecules. When ionized air contacts a charged surface, for example, the photoresist particles are driven toward the wafer substrate by electrostatic forces that attract ions of the opposite pole. Therefore, the electrostatic force is neutralized, and the photoresist particles can be more easily removed from the wafer substrate during the pre-wetting process.

In some embodiments, the pre-wetting process performed on the wafer substrate through which the photoresist is to be plated may be performed using a pre-wet chamber having a pre-wet fluid velocity or flow rate without any setting. In such embodiments, it is preferred to use additional mechanisms to loosen the particles. For example, the pre-wetting chamber can include a megasonic transducer that can be rotated and activated over the wafer substrate after the pre-wet chamber is pre-wet processed. The ultrasonic actuator can release the photoresist particles of the wafer substrate. Alternatively, the ultrasonic actuator can be provided in any of the pre-wet chambers described herein to assist in the removal of particles from the wafer substrate. In some embodiments, the pre-wet treatment with ultrasonic degassing can be performed in degassed deionized water in a vacuum.

The through-resistive plating pre-wetting apparatus may include a hardware that performs the processing operations as described above, and a system controller (not shown) that controls the processing operations in accordance with the disclosed embodiments. The system controller can include one or more memory devices and one or more processors to execute the instructions to enable the device to perform the methods in accordance with the embodiments disclosed herein. Such instructions may include, for example, evacuating the pre-wet chamber, rotating the wafer at one or more speeds, flowing the degassed pre-wetting fluid through the manifold into the chamber during a particular period of time and during a particular rotational speed of the wafer substrate Stop the flow of the degassing fluid, stop or slow the rotation of the wafer substrate, pressurize the chamber, and remove the wafer substrate. Various combinations of the above operations can be edited into programs with appropriate instructions. A machine readable medium containing instructions for controlling processing operations in accordance with the disclosed embodiments herein can be coupled to a system controller.

Figure 13 is a flow diagram of an embodiment of a pre-wet treatment (1600) for through-resistive plating. A wafer substrate (1605) having a recess feature such as an opening in the photoresist layer is provided in a pre-wet processing chamber such as chamber 1350, 1400 or 1500. In the case of through-resistive plating, the bottom of the recess feature contains metal and additional metal is electroplated onto the metal after pre-wetting. Within the processing chamber, the wafer substrate is loaded onto a wafer support or chuck such as components 1356, 1406, 1506. After the wafer substrate is properly placed in the pre-wet processing chamber, the processing chamber pressure is reduced to sub-atmospheric pressure (1610). Partially, the pre-wet fluid is degassed (1615). In common with some of the foregoing embodiments, the fluid can be degassed in separate degassing elements. Degassing can be performed simultaneously with the other operations shown in FIG. crystal After the circular substrate is properly mounted in the processing chamber, rotation begins (1620). In a particular embodiment, the rotation begins before or during the chamber pressure drop (1610) and/or fluid outgas (1615). After the chamber pressure is reduced to the desired level, the wafer substrate is brought into contact with the degassed pre-wet fluid at sub-atmospheric pressure while the wafer substrate is rotating. This forms a wetting layer (1625) on the surface of the wafer substrate. In a particular embodiment, the degassed pre-wetting fluid contacts the wafer substrate at a rate sufficient to release any particles on the exposed metal layer and a flow rate sufficient to remove the loose particles from the wafer substrate. In various examples, the linear velocity of the fluid in contact with the wafer substrate is at least about 5 m/s, and the volumetric flow of fluid on the wafer substrate is at least about 0.3 L/min. In some embodiments, the pre-wetting fluid can be a deionized water or chemical solution that assists in releasing and removing particles from the wafer substrate. This pre-wetting treatment can be carried out using the pre-wet device design described herein. Furthermore, the pre-wet devices and processes described herein can be used to remove any type of particles or impurities from the wafer substrate.

The apparatus/methods described herein can be used with lithographic patterning tools or processes, such as the fabrication of semiconductor devices, displays, LEDs, photovoltaic panels, and the like. In general, but not necessarily, such tools/processes may be used or operated together in a common manufacturing facility. Thin film lithography patterning typically includes some or all of the following steps, each step being performed by various tools: (1) applying a photoresist to the workpiece (ie, the substrate) using a spin coating or spray coating tool; (2) utilizing a hot plate Or furnace or UV hardening tool to harden the photoresist; (3) use a tool such as a wafer stepper to expose the photoresist to visible light, UV or X-ray; (4) develop with a tool such as a wet bench a photoresist to selectively remove the photoresist thereby patterning it; (5) transferring the photoresist pattern to the underlying film or workpiece using a dry or plasma-assisted etching tool; and (6) utilizing Tools such as RF or microwave plasma photoresist strippers remove photoresist.

The invention has been described with reference to the specific details of the invention, and the specific changes and modifications are within the scope of the claims. It should be noted that there are many alternative ways to implement processing and composition. Accordingly, the embodiments are merely illustrative and not limiting, and the embodiments are not limited to the details.

1600‧‧‧Process

1605, 1610, 1615, 1620, 1625‧‧ steps

Claims (22)

An apparatus comprising: a degasser for removing one or more dissolved gases from a pre-wetting fluid to produce a degassed pre-wet fluid; and a processing chamber comprising: a wafer holding portion for holding the wafer substrate And for rotating the wafer substrate; a vacuum crucible for forming a sub-atmospheric pressure in the processing chamber; and a fluid inlet portion coupled to the deaerator and for using the degassed pre-wet fluid at least about every a speed of 7 meters per second is delivered to the wafer substrate; and the controller includes a program command for: rotating the wafer substrate at a first rotational speed; and by rotating the first rotational speed The wafer substrate is brought into contact with the degassed pre-wet fluid from the degasser, and the degassed pre-wet fluid is introduced from the fluid inlet portion at a flow rate of at least about 0.4 liters per minute. The degassed pre-wet fluid is in a liquid state such that a wetting layer is formed on the wafer substrate at the sub-atmospheric pressure within the processing chamber. The apparatus of claim 1, wherein the fluid inlet portion includes a nozzle for conveying the degassed pre-wetting fluid to the wafer substrate, and wherein the nozzle is disposed in the processing chamber On the side wall. The apparatus of claim 2, wherein the nozzle is a fan-shaped nozzle for conveying the degassed pre-wetting fluid onto the wafer substrate to cause the removal of the wafer substrate The pre-wetting fluid of the gas has a linear shape. The apparatus of claim 1, wherein the fluid inlet portion comprises a manifold, the manifold comprising at least one nozzle for delivering the degassed pre-wet fluid to the wafer substrate, and wherein the nozzle is located Above the wafer substrate. The apparatus of claim 4, wherein the at least one nozzle comprises a fan nozzle for conveying the degassed pre-wetting fluid onto the wafer substrate to cause impact on the wafer base The degassed pre-wet fluid of the plate has a linear shape. The apparatus of claim 4, wherein the processing chamber comprises a cover and a body, wherein the cover remains stationary, and the body is configured to move substantially vertically to cause the body to contact the cover to form a vacuum seal, and wherein The nozzle is attached to the cover. The apparatus of claim 4, wherein the nozzle is configured to transport the degassed pre-wetting fluid from an edge of the wafer substrate to a substantial center of the wafer substrate. The device of claim 1, wherein the wafer holding portion is configured to hold the wafer substrate in a substantially upward facing orientation. The apparatus of claim 1, wherein the degasser comprises a membrane contact degasser. The apparatus of claim 1, wherein the degasser is for generating a dehumidified pre-wet fluid having a dissolved atmospheric gas of about 0.5 ppm or less for contacting the wafer substrate. The apparatus of claim 1, wherein the pre-wetting fluid is at least one of a deionized water and a chemical solution that assists in releasing and removing particles from the wafer substrate. The apparatus of claim 1, wherein the vacuum crucible is located below the wafer holding portion. The apparatus of claim 1, wherein the processing chamber is configured to maintain a sub-atmospheric pressure of less than about 50 Torr during formation of the wetting layer on the wafer substrate. The device of claim 1, wherein the program instruction further comprises: after forming the wetting layer on the wafer substrate, stopping the delivery of the degassed pre-wet fluid; and stopping the delivery of the degassing pre-process After the wet fluid, the wafer substrate is rotated at a second rotational speed to remove excess surface from the wafer substrate to remove the degassed pre-wetting fluid. The apparatus of claim 14, wherein the program instruction further comprises the following instructions: after stopping the delivery of the degassed pre-wet fluid, and before removing the excess surface to remove the degassed pre-wetting fluid, The pressure in the processing chamber is increased to or above atmospheric pressure. The apparatus of claim 1, wherein the program instructions further comprise the step of reducing the pressure of the processing chamber to the sub-atmospheric pressure prior to forming the wetting layer on the wafer substrate. The apparatus of claim 1, wherein the program instructions further comprise the step of initiating the step of forming the wetting layer on the wafer substrate when the pressure of the processing chamber drops below about 50 Torr. The apparatus of claim 1, wherein the program instructions further comprise the step of contacting the wafer substrate with the degassed pre-wetting fluid for about 10 to 120 seconds. A method comprising: (a) disposing a wafer substrate in a processing chamber, the wafer substrate having an exposed metal layer on at least a portion of a surface thereof; (b) reducing a pressure of the processing chamber to a sub-atmospheric pressure; (c) degassing the pre-wet fluid; (d) rotating the wafer substrate; and (e) contacting the rotating wafer substrate with the degassed pre-wet fluid in the processing chamber at the sub-atmospheric pressure, To form a wetting layer on the wafer substrate, the degassed pre-wet fluid contacts the wafer substrate at a rate of at least about 7 meters per second and at a flow rate of at least about 0.4 liters per minute. The method of claim 19, further comprising: applying a photoresist to the wafer substrate; exposing the photoresist to light; patterning the photoresist and transferring the pattern to the wafer substrate; The photoresist is selectively removed from the workpiece. A non-transitory computer-readable medium containing program instructions for controlling a device, the program instructions including code for: (a) providing a wafer substrate in a processing chamber, the wafer substrate having at least a surface thereof a portion having an exposed metal layer; (b) reducing the pressure of the processing chamber to sub-atmospheric pressure; (c) degassing the pre-wetting fluid; (d) rotating the wafer substrate; and (e) processing the wafer The rotating wafer substrate contacts the degassed pre-wet fluid at the sub-atmospheric pressure to form a wetting layer on the wafer substrate, the degassed pre-wetting fluid being at least about 7 sec per second. The speed of the ruler and the flow rate of at least about 0.4 liters per minute contact the wafer substrate. A system comprising a device of claim 1 and a stepper.