Patent ID: 12226807

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Electrochemical deposition may be employed at various points in the integrated circuit fabrication and packaging processes. At the integrated circuit (IC) chip level, damascene features are created through electrodepositing copper within vias and trenches to form multiple interconnected metallization layers. However, after electrochemical deposition is performed on several batches of wafers, contamination is found on the substrate holder, which may induce inline gap-filling defects during the electrochemical deposition, and thus to deteriorate the process yield. Specifically, the contamination may be dropped into the vias or the trenches, which may result in the gap-filling defects. The contamination may be particles, unwanted deposits, recrystallized components (e.g., copper sulfate or a mixture of copper sulfate and additive) or other materials. What is needed therefore is improved technology for removing the contamination on the substrate holder.

Currently, the substrate holder is cleaned by immersing the substrate holder into the electroplating bath to remove the contamination on the substrate holder. Nevertheless, such cleaning process typically takes more than ten minutes. Furthermore, the cleaning process may be performed with high frequency, and thus will significantly lower wafer throughput per hour (WPH).

Therefore, the present disclosure provides a cleaning device for effectively removing contamination on a substrate holder used with an electroplating cell. In some embodiments, the cleaning process using the cleaning device takes less than or much less than ten minutes, and thus will improve the wafer throughput per hour (WPH). Embodiments of the electroplating cell, the substrate holder and the cleaning device are sequentially described in detail below.

In some embodiments, the electroplating cell (not shown) has an electroplating chamber, which may house an anode chamber and an electroplating solution. In some embodiments, the electroplating cell further includes other functional elements, such as a diffuser, an electroplating solution inlet tube, a rinse drain line, an electroplating solution return line, any other functional element or a combination thereof.

In some embodiments, the electroplating cell is included in an electroplating tool (not shown) for electroplating semiconductor wafers. Semiconductor wafers may be fed to the electroplating tool. A robot can retract and move the substrates in multiple dimensions from one station to another station. The electroplating tool may also include other modules configured to perform other necessary electroplating sub-processes, such as spin rinsing and drying, metal and silicon wet etching, pre-wetting and pre-chemical treating, photoresist stripping, surface pre-activation, etc.

The substrate holder is used with the electroplating cell. The substrate holder is configured to receive and support a substrate (e.g., a semiconductor wafer) during electroplating deposition. The term “substrate holder” may also be called as wafer holder, workpiece holder, clamshell holder, clamshell assembly and clamshell. In some embodiments, the substrate holder is Novellus Systems' Sabre® tool. In some embodiments, the substrate holder can be lifted vertically either up or down to immerse the substrate holder into the electroplating solution in the electroplating cell via an actuator.

In some embodiments, the substrate holder (not shown) includes two main components of a clamshell, which are a cup and a cone. In some embodiments, the cup is configured to provide a support upon which the substrate rests. In some embodiments, the cone is over the cup and configured to press down on a backside of the substrate to hold it in place. In some embodiments, the substrate holder further includes struts to support the cup and the cone. In some embodiments, the substrate holder is driven by a motor. In some embodiments, the substrate holder is driven by a motor via a spindle. In some embodiments, the spindle transmits torque from the motor to the substrate holder causing rotation of the substrate held therein during the electroplating process. In some embodiments, an air cylinder within the spindle also provides a vertical force for engaging the cup with the cone. In some embodiments, the substrate is loaded between the cone and the cup when the clamshell is disengaged. The cone is engaged with the cup after the substrate is loaded to engage the substrate against the periphery of the cup.

In some embodiments, the cup includes a cup bottom, a plurality of lip seals and a plurality of electrical contacts. In some embodiments, the lip seals and the electrical contacts surround the cup bottom, and the electrical contacts are over the lip seals.

FIG.1is a cross-sectional view of a portion of a cup in accordance with some embodiments of the present disclosure, which shows a portion of the cup bottom212, one of the lip seals214and one of the electrical contacts216. The cup and its components may have an annular shape and be sized to engage the periphery of a substrate300(e.g., a 200-mm wafer, a 300-mm wafer, a 450-mm wafer).

The cup bottom212is also referred to as a “disk” or a “base plate.” The cup bottom212may be made of a stiff, corrosive resistant material, such as stainless steel, titanium, and tantalum. The cup bottom212may be removed (i.e., detached) to allow replacing various elements of the cup. The cup bottom212may have a tapered edge (not marked) at its innermost periphery, which is shaped in such ways as to improve flow characteristic of the electroplating solution around the edge.

During closing, the cup bottom212supports the lip seals214when the force is exerted through a substrate300to avoid clamshell leakage during the substrate300immersion. That is, the lip seals214are configured to engage with the edge of the substrate300and to form a seal between the substrate300and the lip seals214that protects the interior of the cup from the electroplating solution. In some embodiments, the lip seals214are made of an elastic material or any other suitable material.

The electrical contacts216are configured to establish electrical connection with conductive elements of the substrate300. In some embodiments, the electrical contacts216are made of alloy or any other suitable material. In some embodiments, the electrical contacts216are flexible and may be pushed down (i.e., towards the tapered edge of the cup bottom212) when the substrate300is loaded.

In order to effectively remove the contamination on the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof ofFIG.1), the present disclosure provides embodiments of the cleaning device described in detail below.

In some embodiments, the cleaning device is an auto-clean-etch (ACE) module and exhibits multiple process capability and high contamination removal efficiency, and thus able to maintain stable peak current during the electroplating process and to reduce gap-filling defects and to improve wafer throughput per hour (WPH). For example, the multiple process capability may include multiple selections of the cleaning agent and multiple parameters (e.g., order, temperature) of the cleaning process.

FIG.2is a cross-sectional view of a cleaning device10in accordance with some embodiments of the present disclosure. As shown inFIG.2, the cleaning device10includes an arm110, a cleaning agent supplier120, a nozzle130and a receiver140(or called as accommodator).

In some embodiments, the arm110is coupled to the nozzle130and configured to position the nozzle130to effectively remove the contamination on the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof). In some embodiments, the arm110is positioned by a controller (not shown). In some embodiments, the arm110is able to move or rotate.

In some embodiments, the arm110is coupled to the cleaning agent supplier120. In some embodiments, the arm110is coupled to the receiver140. In some embodiments, the arm110is connected to the receiver140. In some embodiments, as shown inFIG.2, the arm110is connected to a bottom (not marked) of the receiver140. In some embodiments, the arm110and the receiver140are integrally molded. In other embodiments, the arm is connected to a sidewall of the receiver. In other embodiments, the arm includes a vertical portion and a connected portion connected between the vertical portion and the receiver. In some embodiments, the vertical portion is coupled to a controller.

In some embodiments, the cleaning agent supplier120is configured to supply a cleaning agent. In some embodiments, the cleaning agent supplier120includes one or more piping lines (not marked) for transferring the cleaning agent to one or more nozzles130. In some embodiments, the cleaning agent supplier120is embedded in the arm110, as shown inFIG.2. In some embodiments, the cleaning agent supplier120is embedded in the receiver140, as shown inFIG.2. In other embodiments, the receiver has a through hole, and the cleaning agent supplier (e.g, a piping line) is inserted in the through hole.

In some embodiments, the cleaning agent supplied from the cleaning agent supplier120includes acid, dry solvent, inert gas, any other suitable material or a combination thereof. In some embodiments, the acid is used to dissolve or etch the contamination. In some embodiments, the acid includes organic acid, inorganic acid or a combination thereof. In some embodiments, the inorganic acid includes sulfuric acid, hydrochloric acid, nitric acid, any other suitable inorganic acid or a combination thereof. In some embodiments, the dry solvent includes isopropyl alcohol (IPA), acetone, methyl ethyl ketone (MEK), any other suitable dry solvent or a combination thereof. In some embodiments, the inert gas includes nitrogen, argon, helium, any other suitable inert gas or a combination thereof.

In some embodiments, the nozzle130is configured to spray the cleaning agent onto the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof) to remove the contamination. In some embodiments, the nozzle130is coupled to the cleaning agent supplier120. In some embodiments, the nozzle130is connected to the cleaning agent supplier120, as shown inFIG.2. In some embodiments, the nozzle130is acted as an outlet of the cleaning agent supplier120, as shown inFIG.2. In some embodiments, the nozzle130has various spray directions. In some embodiments, the spray direction of the nozzle130is adjustable. In some embodiments, the nozzle130is on the receiver140. In some embodiments, the nozzle130is on a sidewall (not marked) of the receiver140, as shown inFIG.2. In some embodiments, the nozzle130is embedded (or inserted) in the receiver140.

In some embodiments, the receiver140is configured to receive the cleaning agent after the cleaning agent is sprayed onto the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof) to avoid contamination of the electroplating solution. In some embodiments, the receiver140is configured to surround the lip seal214. In some embodiments, the receiver140is configured to surround the lip seal214and the electrical contact216. In some embodiments, the receiver140is a sink, which can be used to accommodate a portion of the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof). In some embodiments, the receiver140includes a vent142on the receiver140and configured to suck up the cleaning agent to avoid overflow of the cleaning agent. In some embodiments, the vent142is on a bottom surface of the receiver140. In some embodiments, the vent142is embedded (or inserted) in a bottom of the receiver140.

FIG.3Ais a cross-sectional view of a cleaning device10in accordance with some embodiments of the present disclosure. As shown inFIG.3A, the cleaning device10includes a receiver140, a cleaning agent supplier120, a first nozzle132and a second nozzle134.

In some embodiments, the receiver140is configured to receive a cleaning agent after the cleaning agent is sprayed onto a substrate holder (e.g., a lip seal214, a electrical contact216, a cup bottom212or a combination thereof) to avoid contamination of the electroplating solution. The receiver140may be designed to various shapes according to the shape of a portion of the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof) and/or other considerations. In some embodiments, the receiver140includes a bottom140a, a ceiling140band a sidewall140cconnected between the bottom140aand the ceiling140b, as shown inFIG.3A.

In some embodiments, the receiver140includes a vent142on the receiver140and configured to suck up the cleaning agent to avoid overflow of the cleaning agent. In some embodiments, the vent142is on the bottom140aof the receiver140. In some embodiments, the vent142is embedded (or inserted) in the bottom140aof the receiver140.

In some embodiments, the cleaning agent supplier120is configured to supply the cleaning agent. In some embodiments, the cleaning agent supplier120includes one or more piping lines (not marked) for transferring the cleaning agent to the first and second nozzles132,134. In some embodiments, the cleaning agent supplier120is embedded in the receiver140, as shown inFIG.3A. In other embodiments, the receiver has a through hole, and the cleaning agent supplier (e.g, a piping line) is inserted in the through hole.

In some embodiments, the first nozzle132is on the ceiling140bof the receiver140and coupled to the cleaning agent supplier120to spray the cleaning agent onto the lip seal214. In some embodiments, the second nozzle134is on the sidewall140cof the receiver140and coupled to the cleaning agent supplier120to spray the cleaning agent onto the lip seal214.

FIG.3Bis a cross-sectional view of a cleaning device10in accordance with some embodiments of the present disclosure. As shown inFIG.3B, the cleaning device10includes a receiver140, a cleaning agent supplier120, a first nozzle132and a second nozzle134.

In some embodiments, the receiver140is configured to receive a cleaning agent after the cleaning agent is sprayed onto a substrate holder (e.g., a lip seal214, a electrical contact216, a cup bottom212or a combination thereof) to avoid contamination of the electroplating solution. The receiver140may be designed to various shapes according to the shape of a portion of the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof) and/or other considerations. In some embodiments, the receiver140includes a bottom140a, a ceiling140band a sidewall140cconnected between the bottom140aand the ceiling140b, as shown inFIG.3B. In some embodiments, the ceiling140bincludes a first portion1401band a second portion1402b. In some embodiments, the second portion1402bis higher than the first portion1401bto fit the shape of a lip seal214.

In some embodiments, the receiver140includes a vent142on the receiver140and configured to suck up the cleaning agent to avoid overflow of the cleaning agent. In some embodiments, the vent142is on the bottom140aof the receiver140. In some embodiments, the vent142is embedded (or inserted) in the bottom140aof the receiver140.

In some embodiments, the cleaning agent supplier120is configured to supply the cleaning agent. In some embodiments, the cleaning agent supplier120includes one or more piping lines (not marked) for transferring the cleaning agent to the first and second nozzles132,134. In some embodiments, the cleaning agent supplier120is embedded in the receiver140, as shown inFIG.3B. In other embodiments, the receiver has a through hole, and the cleaning agent supplier (e.g, a piping line) is inserted in the through hole.

In some embodiments, the first nozzle132is on the first portion1401bof the ceiling140bof the receiver140and coupled to the cleaning agent supplier120to spray the cleaning agent onto the lip seal214. In some embodiments, the second nozzle134is on the sidewall140cof the receiver140and coupled to the cleaning agent supplier120to spray the cleaning agent onto the lip seal214.

In some embodiments, the cleaning device10further includes a third nozzle136on the second portion1402bof the ceiling140bof the receiver140. The first, second and third nozzles132,134and136may align with different portions of the lip seal214. In other embodiments, a plurality of nozzles may align with a same portion of the lip seal. It is noted that, the amount, the position and the spray direction of the nozzles may be altered in practical applications.

In some embodiments, the lip seal214includes a lip portion214aconfigured to be against a substrate (e.g., the substrate300ofFIG.1). In some embodiments, the first nozzle132is substantially or entirely aligned with the lip portion214ato effectively remove the contamination of the lip portion214a. In some embodiments, the first portion1401b, the sidewall140cand the bottom140asurround the lip portion214a.

FIG.4is an illustrative flowchart of a method of removing contamination on a substrate holder in accordance with some embodiments of the present disclosure. In operation402, as shown inFIG.2, the arm110is moved to align the nozzle130with a portion of the substrate holder (e.g., the lip seal214, the electrical contact216, the cup bottom212or a combination thereof). In some embodiments, the arm110is moved using a controller. In some embodiments, during, before or after the arm110is moved, the substrate holder is also moved to help the alignment between the nozzle130and the portion of the substrate holder.

FIGS.5A-5Dare schematic diagrams of aligning a cleaning device10with a portion of a substrate holder20in accordance with some embodiments of the present disclosure. In some embodiments, the substrate holder20shown inFIGS.5A-5Dis simply depicted for clarity. In some embodiments, the substrate holder includes a cup. In some embodiments, the cup includes a cup bottom, lip seals and electrical contacts, as shown inFIG.1.

As shown inFIGS.5A-5D, the cleaning device10includes an arm110, a receiver140, nozzle(s) and cleaning agent supplier(s), and the nozzle(s) and cleaning agent supplier(s) are not shown for simplicity and clarity. In some embodiments, the arm110includes a vertical portion (not marked) and a connected portion (not marked) connected between the vertical portion and the receiver140. In some embodiments, the vertical portion is coupled to a controller. In some embodiments, the receiver140is substantially arc-shaped in top view to fit the portion of the substrate holder20. In some embodiments, a sidewall (not marked) of the receiver140has different heights. The three dimensional shape of the receiver140may be designed according to the shape of the portion of the substrate holder, the position of the nozzle(s) and/or other considerations.

First, as shown inFIGS.5A and5B, the arm110of the cleaning device10is rotated (or moved) to a position beneath the substrate holder20. Subsequently, as shown inFIGS.5B and5C, the substrate holder20is moved down to approach the cleaning device10. In some embodiments, the substrate holder20is moved down to approach the receiver140. In some embodiments, the substrate holder20is moved down by a motor (not shown). In some embodiments, the substrate holder20is moved down by a motor via a spindle (not shown). Finally, as shown inFIGS.5C and5D, the arm110is rotated (or moved) to align the nozzle (not shown) with the portion of the substrate holder20(e.g., the lip seal214, the electrical contact216, a cup bottom212or a combination thereof ofFIG.1). It is noted that, the processing steps ofFIGS.5A-5Dis only an embodiment, and change and other methods may be utilized to align the nozzle with the portion of the substrate holder.

In operation404, the cleaning agent is sprayed (or rinsed) onto the portion of the substrate holder20through the nozzle to remove the contamination, as shown inFIG.5D. In some embodiments, the method further includes rotating the substrate holder20when spraying the cleaning agent onto the portion of the substrate holder20. In some embodiments, rotating the substrate holder20is conducted by the spindle (not shown), which can transmits torque from the motor to the substrate holder. In some embodiments, a rotating speed of the substrate holder20is in a range of 0.1 rpm to 600 rpm, but not limited thereto. In some embodiments, the sidewall of the receiver140adjacent to the portion of the substrate holder20is not in contact with the portion of the substrate holder20. In some embodiments, the nozzle is not in contact with the portion of the substrate holder20.

In some embodiments, spraying the cleaning agent onto the portion of the substrate holder20includes: spraying an acid onto the portion of the substrate holder20; spraying an dry solvent onto the portion of the substrate holder20after spraying the acid onto the portion of the substrate holder20; and spraying inert gas onto the portion of the substrate holder20after spraying the dry solvent onto the portion of the substrate holder. The species of the cleaning agents, the spray order and the spray position may be appropriately changed in other embodiments and not limited to the embodiments exemplified above.

In some embodiments, as shown inFIG.3B, the acid is sprayed on the lip portion214athrough the first nozzle132. In some embodiments, as shown inFIG.3B, the acid is sprayed on the lip seal214and the electrical contact216through the first, second, third nozzles132,134,136. After the acid is sprayed, the dry agent is sprayed on the lip seal214and the electrical contact216through the first, second, third nozzles132,134,136. After the dry agent is sprayed, the inert gas is sprayed on the lip seal214and the electrical contact216through the first, second, third nozzles132,134,136.

In operation406, the cleaning agent is received through the receiver140after the cleaning agent is sprayed onto the portion of the substrate holder20, as shown inFIG.5D. In some embodiments, the receiver140includes a vent (not shown) on the receiver140, and the method further includes sucking up the cleaning agent through the vent when spraying the cleaning agent onto the portion of the substrate holder20or receiving the cleaning agent through the receiver140to avoid overflow of the cleaning agent.

According to some embodiments, a cleaning device for removing contamination on a substrate holder used with an electroplating cell includes an arm, a cleaning agent supplier, a nozzle and a receiver. The cleaning agent supplier is coupled to the arm and configured to supply a cleaning agent. The nozzle is coupled to the cleaning agent supplier and configured to spray the cleaning agent onto the substrate holder to remove the contamination. The receiver is coupled to the arm and configured to receive the cleaning agent after the cleaning agent is sprayed onto the substrate holder.

According to some embodiments, a cleaning device for removing contamination on a lip seal of a substrate holder used with an electroplating cell includes a receiver, a cleaning agent supplier, a first nozzle and a second nozzle. The receiver includes bottom, a ceiling and a sidewall between the bottom and the ceiling. The cleaning agent supplier is configured to supply a cleaning agent. The first nozzle is on the ceiling of the receiver and coupled to the cleaning agent supplier to spray the cleaning agent onto the lip seal. The second nozzle is on the sidewall of the receiver and coupled to the cleaning agent supplier to spray the cleaning agent onto the lip seal.

According to some embodiments, a method of removing contamination on a substrate holder in an electroplating cell using the cleaning device described above includes: moving the arm to align the nozzle with a portion of the substrate holder; spraying the cleaning agent onto the portion of the substrate holder through the nozzle to remove the contamination; and receiving the cleaning agent through the receiver after the cleaning agent is sprayed onto the portion of the substrate holder.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.