KR20200116163A - Electroplating system with inert anode and active anode - Google Patents

Abstract

Methods and electroplating systems for controlling plating electrolyte concentration on an electrochemical plating apparatus for substrates are disclosed. The inert anode (or auxiliary electrode, which can act as an inert anode if necessary) controls the concentration of one or more electrolyte components. The inert anode balances the electrolytic metal ion generation and consumption rate in the plating process by implementing a gas evolution reaction that does not generate metal ions.

Description

Electroplating system with inert anode and active anode

Cross reference to related applications

This application claims the benefit of the priority of U.S. Provisional Application No. 62/634,463, filed on February 23, 2018, entitled "ELECTROPLATING SYSTEM WITH INERT AND ACTIVE ANODES", which is hereby incorporated by reference in its entirety for all purposes. It is cited in the specification.

The present disclosure relates to the control of the electroplating solution concentration, and in particular to such control when performed on an electrochemical plating apparatus for semiconductor substrates.

The electrochemical deposition process is widely used in the semiconductor industry for metallization of IC fabrication. One such application is copper (Cu) electrochemical deposition, which may involve deposition of Cu lines into trenches and/or vias that are pre-formed in dielectric layers. In this process, a thin adhesive metal diffusion-barrier film is pre-deposited onto the surface by utilizing physical vapor deposition (PVD) or chemical vapor deposition (CVD). A thin copper seed layer will then be deposited on top of the barrier layer, typically by a PVD deposition process. The features (vias and trenches) are then electrochemically filled with Cu via an electrochemical deposition process, and copper anions are electrochemically reduced to copper metal during the electrochemical deposition process. Another application is the cobalt (Co) deposition in the same or different contexts.

This background section is intended to provide the context of this disclosure. To the extent presented in this background section or other portions of the description not otherwise certified as prior art, the work by the inventors is not admitted as prior art to the present disclosure.

In an electrochemical plating apparatus having separated anolyte portion and catholyte portion and an active anode of the anolyte portion, the concentration of catholyte components (e.g., acids, anions, cations, additives, etc.) is active. It can also be controlled by using an inert anode together with the anode. The inert anode may also balance the rate of metal cations generation and consumption in the plating process by initiating a hydrogen ion generation reaction that does not produce metal cations. The inert anode accommodates the fraction of the total anode current (relative to the active anode) of the device such that metal cation generation (at the active anode) and hydrogen ion generation (at the inactive anode) are the desired ratios. This ratio may be based on the current efficiency of the plating reaction at the cathode (a workpiece or substrate such as a semiconductor wafer). The fraction of current delivered to the inert anode can be determined in various ways, such as the active anode and the relative electrolyte facing surface areas of the inert anode, by a circuit that divides the current between the anodes, and/or by the inert anode (again compared to the active anode). It can also be controlled according to the fraction of time it operates. In other words, an inert anode is available, but it may only be used to a limited, often at least in part, extent determined by the current efficiency of the plating onto the cathode. For example, an inert anode may only operate during 30% of the electroplating run.

One aspect of the present disclosure relates to a method of electroplating metal on a substrate during fabrication of a device. This method includes the following operations: (a) (i) a cathode portion configured to hold a substrate while electroplating a metal on the substrate, (ii) an electroplating solution comprising ions of the metal, (iii) an active anode, And (iv) providing an electroplating solution to the electroplating system comprising an inert anode; (b) providing a first fraction of the total current to the active anode to electroplate metal on the substrate; And (c) providing a second fraction of the total current to the inert anode for electroplating the metal on the substrate. In these methods, the first fraction and the second fraction may each approximate the fractions of metal plating and one or more parasitic reactions in the substrate. In addition, providing a first fraction of the total current and providing a second fraction of the total current causes the metal to be electroplated onto the substrate.

In certain embodiments, the metal is cobalt, and the active anode comprises cobalt. In certain embodiments, one or more parasitic reactions include hydrogen ion reduction. In certain embodiments, the electroplating solution includes cobalt ions, acids, borate ions, and organic plating additives.

One aspect of the present disclosure relates to a system for electroplating metal onto a substrate during manufacture of a device. Such a system comprises the following elements: (a) an electroplating cell comprising an anode portion and a cathode portion, and configured to hold a substrate in the cathode portion while electroplating metal on the substrate; (b) an active anode comprising a metal; (c) an inert anode; And (d) a controller. In some implementations, the controller (i) provides a first fraction of the total current to the active anode to electroplat metal on the substrate, and (ii) the control of the total current to electroplat metal on the substrate. Include instructions to provide 2 fractions to the inert anode. The first fraction and the second fraction may each approximate the fractions of metal plating on the substrate and one or more parasitic reactions.

In some embodiments, the electroplating system further includes an ion transfer separator configured to provide a path for ion communication between the anode portion and the cathode portion, and between the anode portion and the electroplating solution of the cathode portion. The ion transfer separator may also include a cation exchange membrane. In certain implementations, the electroplating cell additionally includes one or more auxiliary electrode chambers, which may include one or more auxiliary cathodes.

In some embodiments, the device may be an integrated circuit. In some embodiments, the metal may be copper and/or cobalt.

These and other features will be described below with reference to the associated drawings.

Exemplary embodiments will now be described in conjunction with the drawings.
1 is a schematic diagram of an exemplary plating electrolyte, or electroplating solution, recirculation and/or dosing system.
Figure 2 is an electroplating bath-side vs. The metal ion splitting effect is illustrated.
3A-3C show various graphs illustrating electroplating bath concentration trends without supplemental or secondary, electroplating solution introduction into the system.
4A-4C are various graphs illustrating electroplating bath concentration trends using, for example, an acid dose to replenish an acid, and a deionized (DI) water dose to control the cobalt ion concentration [CO ²⁺ ]. Show them.
5A and 5B show an exemplary system with an inert anode and an active anode positioned both in the anode portion of the electroplating system.
6A and 6B illustrate an exemplary system with an auxiliary cathode serving as an inert anode during part of the electroplating cell operation.
7A and 7B show an exemplary system with an inert anode used with an auxiliary cathode.
8 shows a schematic diagram of a top view of an exemplary electrodeposition device.
9 shows a schematic diagram of a top view of an alternative exemplary electrodeposition device.
10 shows a cross-sectional view of an electroplating cell present in an anode chamber with both an inert anode and an active anode.

In the following description, a number of specific details have been set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process steps have not been described in detail so as not to unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with specific embodiments, it will be understood that they are not intended to limit the disclosed embodiments.

Introduction and background

Control of the composition and concentration of the electroplating solution used in the electroplating system may be important to the performance of the electrochemical deposition process. Typically, there are a plurality of components in a predetermined electroplating solution. For example, the composition of the electroplating solution used for the deposition of copper on a wafer may vary, but may contain a mixture of sulfuric acid, copper salts (e.g. CuSO ₄ ), chloride ions, and organic additives. have. In the case of cobalt deposition, the composition of the electroplating solution may include a mixture of sulfuric acid, boronic acid, a cobalt salt (eg CoSO ₄ ), and organic additives. The composition of the electroplating solution is selected to balance the rate and uniformity of the electroplating in an area without features formed on or within the wafer's internal features or within the field of the wafer, for example. During the plating process, the cobalt salt serves as a source of cobalt cations and also provides conductivity to the electroplating solution; Also, in certain embodiments, sulfuric acid improves electroplating solution conductivity by providing hydrogen ions as charge carriers. In addition, organic additives, generally known in the art as accelerators, inhibitors, and/or leveling agents, can selectively enhance or inhibit the rate of cobalt deposition on different surfaces and wafer features. Boronic acid is useful for buffering electroplating solutions.

Separation of the anodic and cathodic regions of the electroplating cell by a semi-permeable membrane may be desirable because the chemical processes occurring at the anode and at the cathode during electroplating may not be compatible. For example, particles that do not dissolve during operation may form on the anode. Protection of the wafer from these undissolved particles is desirable to prevent interference of these particles with subsequent metal deposition processes performed on the wafer. In addition, restriction of organic additives to the cathode portion of the plating cell may also be desirable to prevent these additives from contacting and/or reacting with the anode. While a suitable separating membrane may allow the flow of ions and thus a current between the anodic and cathodic regions of the plating cell, it still restricts unwanted particles and/or organic additives from passage through the separating membrane. Thus, the use of a separation membrane during electrodeposition will create different chemical atmospheres in the cathodic region and the anodic region of the plating cell equipped with the separation membrane. The electrolyte contained in the anodic region of the plating cell may be referred to as “anolyte”. Similarly, the electrolyte contained in the cathodic region of the plating cell may be referred to as “catholyte”.

An electroplating apparatus having a membrane for separating the anodic region from the cathodic region is described in more detail in US Pat. No. 6,527,920 to Msyer et al. entitled “Copper Electroplating Apparatus”, which is incorporated herein by reference in its entirety. As discussed above, this separating membrane allows electric current to flow between the anodic and cathodic regions, but may be further configured to selectively limit the current flow depending on the type of ions. That is, the membrane separating the catholyte from the anolyte may demonstrate selectivity for different types of ions. For example, for Cu or Co plating applications, the separating membrane allows the passage of hydrogen ions (H ⁺ ) faster than the rate of passage of copper or cobalt ions, for example Cu ^{2 +} , Cu ⁺ or Co ^{2 +} You can also allow Depending on the selectivity of the membrane, the mobility of certain types of ions or current is more generally by hydrogen ions, for example, until a certain molar ratio between the Cu ^{2 +} concentration and the H ⁺ concentration is achieved. It can also be mainly conveyed. After the ratio has been achieved, the sex of the anode portion of the electrochemical cell, Cu ^{2 +,} and acid concentration of the copper ions and hydrogen ions to be stabilized may also begin to carry the current proportionally across the membrane. Thus, until a certain molar ratio between copper ions and hydrogen ions is achieved, since the hydrogen ions are the main current carriers under these conditions, the acidic component of the anolyte may be continuously depleted. Simultaneously with the supply of the acidic component of the anolyte, the concentration of the copper salt rises, especially when a copper containing anode is used. This effect, for example, the depletion of acid from the anolyte with the same degree of rise of the copper salt is the “acid/metal ion splitting effect” occurring inside the anode chamber, or “anode because the acid is depleted at the anode over time. It may also be referred to in the art as "chamber depletion effect".

The acid/metal splitting processes described above may also unintentionally cause some undesirable side effects on the plating system. Some of these side effects are described in US Pat. No. 8,128,791 to Buckalew et al. (791 patent herein) entitled “Control of Electrolyte Composition in Copper Electroplating Apparatus”, which is incorporated herein by reference in its entirety. Undesirable side effects include potential crystallization, or precipitation, of excess salt from the electroplating solution onto the anode surface inside the anode chamber. In addition, water may seep across the membrane due to the electro-osmotic effect by creating a pressure gradient between the anodic and cathodic parts of the device, which may ultimately lead to membrane damage and failure. . U.S. Patent No. 8,128,791 describes ways to control the anodic electrolyte composition by frequently replenishing the anode chamber with a plating electrolyte. This process may also be referred to in the art as “bleed and feed”. As an alternative to bleed and feed, diluted electrolyte may be added into the anode chamber of the plating cell.

The acid and cation splitting effects, described above, may also create undesirable fluctuations in electroplating solution concentration on the cathodic side of the electroplating cell, which in turn may affect the electroplating process performance. Some examples are described below.

In addition to the partition effect, concentration changes in the anode and cathode portions of the system may result from electroplating current inefficiencies. The current efficiency defines the metal plating (Me ⁺ + e → Me) current as a percentage of the total current received by the cathode. Inefficiency is a function of the employed electrochemical. While copper is generally plated on semiconductor substrates with high current efficiencies (reaching 100%), cobalt is usually plated on these substrates with significantly lower current efficiencies (e.g., about 50 to 90%). Plated. In the cobalt plating process, the plating current efficiency is mainly determined by the ability of protons at the substrate surface. Plating current inefficiencies may thus increase at lower plating current densities, since a significant portion of the current is carried by hydrogen ion reduction on the surface.

In detail, the current efficiency of the metal plating process represents the contention between metal deposition (mainly Me ⁺ + e → Me) and hydrogen ion reduction (H ⁺ + e → H ₂ ). Each of the reactions may be characterized by a reduction potential; The more positive the reduction potential is, the easier the reaction proceeds. Considering the three related reactions, the standard reduction potentials are: Cu ^{2 +} + 2e → Cu, 0.337 V; 2H ⁺ + 2e → H ₂ , 0 V; Co ^{2 +} + 2e → Co, -0.28 V. In the copper deposition reaction, Cu deposition is thermodynamically preferable compared to hydrogen ion reduction, so that the current efficiency of the deposition reaction is usually relatively high. However, when copper ions are supplied at a rate lower than the total deposition rate dictated by the applied current density, the current efficiency drops. At high currents, which may be outside the limit current, the copper plating current efficiency is degraded. In cobalt deposition processes, since hydrogen ion reduction is thermodynamically advantageous for cobalt deposition, the current efficiency of plating cobalt increases when hydrogen ions are supplied slowly compared to the overall deposition rate. Therefore, at high plating currents, especially when relatively low acid concentration electrolytes are used, the cobalt current efficiency may be increased.

In an exemplary plating reaction, metal (eg Co) is removed from the anode via the following reaction: Co → Co ^{2 +} + 2e. However, on the cathode surface, due to the plating current-efficiency lower than 100% for metal plating, two reactions: Co ^{2 +} + 2e → Co and 2H ⁺ + 2e → H ₂ occur simultaneously. The amount of current consumed by each of the reactions varies between plating process settings. Over a long period of time, the net effects on the plating bath electrolyte (of the de-plating process at the anode and the plating process at the cathode) are: (1) more released from the anode than is consumed at the cathode. (release) the metal ion concentration rises; (2) acid concentration is reduced because acid is not supplied from the anode and is consumed only on the cathode; (3) The boronic acid concentration does not change because boronic acid is not involved as an activity in the reaction. This is illustrated in FIGS. 3A to 3C. Note that if the acid metal ion splitting effect occurs on the anode side and the amount of charge carried by the acid through the membrane is significant, the metal ion and acid concentration can be shifted even further. However, in some applications, due to the much lower acid concentration compared to the metal ion concentration, the splitting effect becomes negligible.

With the net consumption of acid from the plating electrolyte, acid addition/dosing to the plating bath is typically implemented in electroplating systems. The metal ion concentration is also controlled, for example by diluting the electroplating solution; In some cases deionized water is added. As a result of dosing of both the acid and DI water, the boronic acid concentration decreases. This is illustrated in Figures 4A-4C. Since boronic acid (any other component of similar function in other metal electroplating solutions) may require a specific concentration for the metal electroplating process, its concentration must be raised by some mechanism.

Dosing and similar modes of controlling the composition of the electroplating solution in the anode and cathode portions of the electroplating system can be expensive. High replenishment rates of electroplating solution components can make the plating process incredibly costly.

To understand the phenomenon discussed above, a typical electrolyte management system is illustrated in FIG. 1. As shown, there are several major segments in the electrolyte management system 100, for example the anode solution loop 132 and/or the cathode solution loop 118. Typically, there is a central bath 102 that provides an electroplating solution to the plating cell 148 and the main cathode chamber 122. The central bath 102 includes a solution recycle loop (not shown in FIG. 1). Additionally, in certain embodiments or configurations, the central bath may also have a temperature control, and a dose system for the dosing of additive doses, deionized water (DI) doses, and other active bath components. Further, in some embodiments, the central bath 102 may have a draw or overflow line 146 away from the central bath 102 to remove unwanted electroplating solution when appropriate. Moreover, in the plating apparatus, a plating cell 148 having separate anodic and cathodic portions, an anodic portion, such as a main anode chamber 126, has a dedicated recirculation loop 132, and a dose line (not shown in FIG. 1 ). City), and overflow and/or withdrawal lines (not shown in FIG. 1). In this configuration, the main cathode chamber 122 receives the plating electrolyte from the central bath 102, circulates the electrolyte toward the plating cell 148 by the feed line 112, and withdraws the cell and/or overflow. It may be configured to overflow directly back to the central plating bath 102 by line 142. Those of skill in the art will recognize that the configuration shown in FIG. 1 is exemplary and that many other suitable configurations may exist without departing from the scope of the present disclosure.

The electrolyte management system 100 shown in FIG. 1 is secondary, or supplemented, with various system 100 components to control undesirable electroplating solution concentration fluctuations on the cathodic side or the anodic side of the plating cell 148. , It will be used to describe variations in system 100 related to supplying electrolyte. In general, the system 100 shown in FIG. 1 is a cathode solution loop 118 and a cathode solution loop 118, which may be in fluid communication with each other through a bath 102 contained in an electroplating solution reservoir 150, in certain embodiments. And an anode solution loop 132. During normal operation of the system 100, an incoming plating electrolyte, sometimes referred to as a make-up solution, having a defined concentration of metal ions and acids in the solution is provided to the system 100 via line 108. Various control points 110, such as valves, pressure, and/or flow controllers, on line 108 and/or in other similar lines to regulate fluid flow through the line on which the control point 110 is installed. It can also be installed. Similarly, mixing point 112 may receive fluid flow from inlet line 108. Mixing points 112 may similarly be installed as needed throughout the system 100 to control the amount and delivery of fluid flowing through the lines 108, etc.

Accordingly, the incoming plating electrolyte may flow through the adjustment point 110 to enter the bath 102 to accumulate in the reservoir 150 intended to hold the bath 102. In certain embodiments, organic additives flow through line 104 into bath 102. Similarly, deionized water (DI) may flow into bath 102 through line 106 to adjust the concentration levels of the various components, or components of bath 102. Operation of the system 100 may involve pumping the fluid bath 102 through line 116 towards the cathode side 122 of the plating cell 148 for accumulation therein. In certain embodiments, the cathode 128 may be at least partially submerge within the cathode side 122 and be electrically connected to the anode 130, the anode side to complete the electrical circuit 134 (126) It can also be contained within. Also, the current (or more precisely the electrons carrying the current) is generally from the negatively charged anode 130 to the positively charged cathode 128. The current drives the reaction of metal ions, e.g., cobalt ions, Co ²⁺ of a solution with an acid in the side of the cathode, or in the compartment 122, so that the plating cell 148, as shown in FIG. Allows electroplating of this metal on the wafer 200 located on the cathode side 122 of the.

The solution from the cathode side 122 may be pumped back to the bath 102 via the cell overflow, or withdrawal, line 138 as needed. Similarly, solution from the anode side 126 may also be pumped to the bath 102 through the anode withdrawal line 142 as needed. The overflow from bath 102 may be intermittently pumped from system 100 via bath overflow, withdrawal, line 146, which may be more commonly referred to as bath dose and overflow control loop 144. In certain embodiments, the bath dose and overflow control loop includes a recirculation pump (not shown), a dose line (not shown), a bath overflow line 146, and a temperature control device and/or mechanism (not shown). You may. It serves as a bleed and feed process along with supplying the make-up solution via line 108 and dumping the electrolyte from the reservoir 150 holding the primary electroplating solution, or bath 102.

As described above, a factor to be considered during the supply to the cathodic side 122 of the plating electrolyte is the acid metal anion splitting effect to perform electroplating on the wafer contained therein. This effect can be observed in the copper plating process and may be applied to other similar plating systems. As illustrated in FIG. 2, on the anode, as shown as Cu ions, e.g., metal ions, or due to the passage of a direct current through the oxidation reaction of Me ⁺ to Cu → Cu ^{2 +} + 2e, the anode It is de-plated into the solution. On the cathode side 122, Cu ^{2 +} ions are extracted from the solution through the reaction of Cu ^{2 +} + 2e → Cu. Similarly, due to the acid carrying a large portion of the plating current, across the membrane 124 on the anode side 126, the anodic electrolyte, enriched with metal ions, slowly depletes acid or H ⁺ ions over time. do. On the cathode side 122, on the wafer 200 contained therein, since metal ions (e.g., secondary copper ions for Cu plating) are removed from the solution upon electroplating or electrodeposition, whereas the separation membrane The solution flowing across (from the anode chamber to the cathode chamber) is acid rich. As mentioned, ion transport through the membrane is better for hydrogen ions than for copper ions. Thus, while the acid concentration therein rises, the copper ion concentration of the cathode side 122 will decrease with time. As described elsewhere, the acid metal ion splitting effect results in a high electrolyte replenishment rate onto the bath 102, in fluid communication with the anodic side 126 and/or with the cathodic side 122 in many configurations. It can also be prevented by adopting it. However, high replenishment rates may unnecessarily waste the electroplating solution and increase the operating cost of the electroplating device.

The acid/metal ion splitting effect may have a significant effect on electroplating solutions having a relatively low metal ion concentration (eg, about 5 g/l or less). In such solutions, a change in concentration as small as grams per tens of liters can have a significant impact on the total concentration of metal ions in the solution and thus the overall electroplating performance. For example, if the target copper ion concentration is about 2 g/l and the concentration drift depletes about 0.6 g/l of copper from the catholyte, the concentration now drops by 30% and the plating performance may therefore experience a significant negative effect. have.

As mentioned, in some systems that employ relatively low acid concentrations (eg, about pH 2-4), the splitting effect may not be significant. However, some such systems (eg, certain cobalt plating systems) may exhibit low metal plating efficiency. The observed fluctuations of cobalt plating are shown in Figures 4A-4C, assuming that dosing is employed to control the acid and cobalt ion concentration of the electroplating solution. As mentioned, the cobalt plating electrolyte may contain cobalt salts, sulfonic acid, organic additives, and boronic acid as a buffer solution.

On the plating apparatus, these are U.S. Patent No. 8,308,931 to Reid et al. entitled "Method and Apparatus for Electroplating", all of which are incorporated herein by reference in their entirety, and U.S. Patents such as Mayer et al., entitled "Method and Apparatus for Electroplating" As disclosed in 8,475,644, it is sometimes desirable to have an auxiliary cathode. In an electrolyte management system, implementing an auxiliary cathode, or auxiliary anode, provides certain advantages. The auxiliary cathodes are usually contained in small isolated chambers to prevent contact with the main cathode (wafer substrate of the plating apparatus), which are usually of a smaller size compared to the main cathode (wafer substrate). Sometimes it is desirable to have a different concentration for the electrolyte in the auxiliary cathode chamber. For example, it is desirable to have a higher anion concentration (than in the plating electrolyte for the main cathode) in the auxiliary cathode chamber so that sometimes higher currents can be applied to the auxiliary cathode.

While the present disclosure presents examples of cobalt and copper electroplating, the present disclosure is not limited to these plating applications. The embodiments and concepts presented herein apply to any metal plating system where the metal plating current efficiency is lower than 100%. Specific examples include those in which the thermodynamic electroplating potential is negative (compared to the potential of the hydrogen ion reduction reaction). Additionally, the disclosed embodiments and concepts apply to plating reactions, where hydrogen ion reduction is the main reaction competing with metal plating, as well as to any plating application in which a parasitic reaction occurs.

Definitions

The following terms are used intermittently throughout this disclosure:

“Substrate”-In this specification, the terms “semiconductor wafer”, “wafer”, “substrate”, “wafer substrate” and “partially fabricated integrated circuit” are used interchangeably. One of skill in the art will understand that the term “partially fabricated integrated circuit” can refer to a silicon wafer during any of the many stages of integrated circuit fabrication from above. Wafers or substrates used in the semiconductor device industry typically have a diameter of 200 mm, or 300 mm, or 450 mm. Further, the terms “electrolyte”, “plating bath”, “bath”, and “plating solution” are used interchangeably. The detailed description assumes that the embodiments are implemented on a wafer. However, the embodiments are not so limited. The workpiece may be of various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that may take advantage of the disclosed embodiments include various articles such as printed circuit boards, magnetic recording media, magnetic recording sensors, mirrors, optical elements, micro-mechanical devices, etc. Includes them.

"Metal"-a material (element, compound, or alloy), preferred for plating onto a substrate or wafer, for the purposes of this disclosure. Examples include copper, cobalt, tin, silver, nickel, and alloys or any combination thereof.

"Electroplated cell"-a cell configured to house an anode and a cathode, typically located opposite one another. Electroplating that occurs on the cathode of an electroplating cell refers to the process of using an electric current to reduce dissolved metal cations to form a thin, cohesive metal coating on the electrode. In certain embodiments, the electroplating cell has two compartments, a compartment for housing the anode and another compartment for housing the cathode. In certain embodiments, the anode chamber and the cathode chamber are separated by a semi-permeable membrane, through which the semi-permeable membrane allows selective movement of concentrations of ionic species. The membrane may be an ion exchange membrane such as a cation exchange membrane. For some implementations, versions of Nafion™ (eg, Nafion 324) are suitable.

"Anode Chamber"-A chamber in an electroplating cell designed to house an anode. The anode chamber may include a support for holding the anode and/or providing one or more electronic connections to the anode. The anode chamber may be separated from the cathode chamber by a semi-permeable membrane. The electrolyte in the anode chamber is sometimes referred to as an anolyte.

"Cathode Chamber"-A chamber in an electroplating cell designed to house a cathode. Often in the context of the present disclosure, the cathode is a wafer-like substrate such as a silicon wafer having a plurality of partially fabricated semiconductor devices. The electrolyte in the cathode chamber is sometimes referred to as catholyte.

“Electroplating solution (or electroplating bath or plating electrolyte)”—a solution of metal ions dissolved in a solution, often with a conductivity enhancing component such as an acid or a base. The dissolved cations and anions are uniformly dispersed through the solvent. Electrically, these solutions are neutral. When an electric potential is applied to this solution, cations of the solution are drawn to the electrode with abundant electrons, while the anions are drawn to the electrode with the defect of electrons.

“Make-up solution”-a type of electroplating solution that typically contains all or almost all components of the primary electroplating solution. A replenishment solution is provided to the electroplating solution to maintain the concentration of the solution components within target ranges, selected to maintain good electroplating performance. This approach is used because the concentrations of the components in the solution vary or drift over time, due to any number of factors as described below. The make-up solution is often provided as a “feed” of the bleed and feed system. The concentrations of the components in the make-up solution are often similar or equal to the target concentrations for these components. Some supplemental solutions do not contain organic plating additives.

"Recirculation System"-provision of fluid materials back into the central reservoir for subsequent reuse. The recirculation system may be configured to effectively reuse the electroplating solution and also to control and/or maintain concentration levels of metal ions in the solution as desired. The recirculation system may include pipes or other fluid conduits with a pump or other mechanism to drive recirculation.

"Target concentration"-the concentration level of metal ions and/or other components in the electroplating solution used to achieve the desired plating performance. In various embodiments, the components of the replenishment solution are provided at target concentrations.

"Active anode"-An anode that donates metal ions to the electroplating solution as an electric current passes through the anode. A cobalt metal anode that donates cobalt ions to the solution during electroplating is an example of an active anode. The electrochemical reaction that occurs at the active anode is often in the form of Me → Me ⁺ + e (assuming that the anode metal produces valent +1 metal ions in solution). The active anode is consumed during electroplating.

“Inert anode”-An anode that does not donate metal ions or other material to the electroplating solution when current passes through the anode. In many systems, the platinum anode is an inert anode. An example of an electrochemical reaction occurring at an inert anode is 2 H ₂ O → 4H ⁺ + O ₂ + 4e. The inert anode is not consumed during electroplating.

The concentrations specified in g/l refer to the total mass of components in grams per liter of solution. For example, a concentration of 10 g/l of component A means that there are 10 grams of component A in one liter volume of a solution containing component A. When specifying the concentration of ions such as copper ions or cobalt ions in g/l, the concentration value refers to the mass of ions alone (not salts or salts from which ions are formed) per unit volume of solution. For example, a copper ion concentration of 2 g/l contains 2 g of copper ions per liter of solution in which the copper ions are soluble. This does not refer to 2 g of copper salt (eg copper sulfate) per liter of solution, but otherwise refers to the mass of anions. However, when referring to the concentration of an acid such as sulfuric acid, methane sulfonic acid, or boric acid, the concentration value refers to the mass of total acid (hydrogen and anion) per unit volume. For example, a solution with 10 g/l sulfuric acid contains 10 g H ₂ SO ₄ per liter of solution.

When specifying concentration values, "substantially same" means within about +/- 5% from the specified target value. For example, a concentration substantially equal to 2 g/l may be in the range of about 1.9 to 2.1 g/l. Otherwise, when specifying concentration values, "significantly deviate from", "is significantly different than" means that the more concentrated component is about 1.3 to 50 times the concentration of the less concentrated component. Note that it means to have a concentration. In some cases, the difference in the target concentration of (a) the secondary electroplating solution and (b) the primary electroplating solution or the concentration of components of the make-up solution is about 5 to 50 times. For example, the concentration of component A is about 5 to 50 times greater in the secondary electroplating solution than in the primary electroplating solution, and vice versa. In another example, the concentration of component A is about 5 to 20 times greater in the secondary electroplating solution than in the primary electroplating solution, and vice versa. In another example, the concentration of component A is about 15 to 30 times greater in the secondary electroplating solution than in the primary electroplating solution, and vice versa.

Electroplating systems using an inert anode with an active anode

As previously described, the component concentration drift of the plating electrolyte may be general. This is particularly true for plating apparatuses having separate annodic and cathodic parts, but need not be limited to this kind of design. To keep both catholyte concentration and anolyte concentration at an acceptable level to ensure acceptable electrochemical plating performance, a common approach to controlling electrolyte concentration is high electrolyte replenish (eg, "bleed and Feed") rate is adopted. However, doing so may significantly increase the operating costs of executing plating processes, and sometimes makes the plating process extremely expensive. In addition, in some cases, the application and use of only high bleed and feed rate may not adequately address problems related to electrochemical plating performance. A second approach that can be used is to have a separate dosing for each and every component of the electrolyte. However, doing so can very complicate the dosing algorithm. Additionally, dosing all components to the plating electrolyte will create a dilution effect on all other components of the plating electrolyte. Thus, the plating apparatus can always be subjected to a dosing/counting state. Accordingly, this approach is generally avoided.

One approach to solving these problems is by adopting a "complementary" secondary electroplating solution, and thus reducing the replenishment rate considerably, while minimizing concentration drift in the electroplating solution. By properly designing the secondary electrolyte, the use of the secondary electrolyte can be minimized so that adopting the secondary electrolyte does not contribute significant additional costs to setting up and implementing the plating apparatus. This application is detailed in PCT patent application PCT/US2018/057105, filed on October 23, 2018 and named by Zhian He et al. as inventors, which is incorporated herein by reference in its entirety. The use of a secondary electrolyte employs inert anodes and may optionally be implemented with the methods and systems described herein.

Certain embodiments described herein employ electroplated cells having an active anode and an inert anode. These cells operate (or are configured to operate) the active and inert anodes in a manner that generates and/or consumes ions to match or approximate the plating efficiency at the workpiece cathode (eg, a semiconductor wafer). For example, an active anode may be operated to generate metal ions and an inert anode may be operated to generate hydrogen ions. The relative amounts of metal ions and hydrogen ions produced by the active and inert anodes may each match the relative amounts of these ions consumed during electroplating on the workpiece. The active anode and the inactive anode may be controlled to produce this result by dividing the total current between the two anodes. Current may be delivered to the two electrodes simultaneously and/or at different times.

In various embodiments, the electroplating cell is an electrochemical reaction that (1) removes metal ions from the electroplating solution by plating on an electrode surface other than the workpiece, and/or (2) does not provide metal ions to the solution. By adding hydrogen ions to the electroplating solution. Operation (1) reduces the concentration of metal ions in the electroplating solution and operation (2) increases the concentration of hydrogen ions in the electroplating solution. Examples of electrodes to which metal may be plated in operation (1) include an auxiliary cathode and an active anode (optionally also used for other purposes). To plate onto the active anode, the electroplating cell is slightly inverted; That is, it operates in such a way that a negative potential is applied to the active anode, which temporarily converts to the cathode.

The electroplating systems disclosed herein employ a power supply with a circuit that divides the current between the inert anode and the active anode. In some implementations, the two anodes are controlled separately by two different power supply units. In other implementations, the two anodes are controlled by two separate channels of the same power supply. In some cases, the anodes are controlled sequentially (separate times or overlapping but distinct times) by the same channel of the same power supply. Regardless of how the power supply is configured, the controller may be employed to control the inert anode and the relative amounts of anode current delivered to the active anode. The relative amounts may be determined at least in part by the current efficiency of the plating reaction on the semiconductor substrate.

In certain implementations, the electroplating system is configured to electroplate cobalt onto a substrate. In the embodiments presented herein, the cobalt electroplating solutions may comprise a cobalt salt (e.g., cobalt sulfate), and an acid (e.g., sulfonic acid), boronic acid, organic additives, and deionized water. have. Typical concentration ranges for these components are about 2 to 40 g/l (Co ^{2 +} ), about 10 to 40 g/l (H ₃ BO ₃ ) (boronic acid), about 0.01 to 0.1 g acid (e.g. For example, sulfonic acid), and about 20 to 400 ppm organic plating additives.

By using an inert anode, the rates of metal ion generation and consumption may be balanced to provide long term electroplating bath stability. The following three examples further elaborate the concepts.

Electroplating system Anode Inert, all located in part Anode And active Anode

As illustrated in FIG. 5A, an inert anode is provided in the plating apparatus as described in FIGS. 1 and 2. In this example, the inert anode may be provided anywhere inside the anode loop. For demonstration purposes, in FIG. 5A, an inert anode is positioned around the active anode. It can also be separated mechanically from the main cathode. It may optionally be electrically connected to the active anode depending on whether it is used simultaneously with the active anode. See Figure 10. When used alone, this approach simply uses a fraction of the anode current to generate hydrogen ions. The active anode and the inert anode together produce metal ions and hydrogen ions at a ratio that approximates the current efficiency of the cathode more closely than would occur if the active anode was used alone. In certain embodiments, the active anode and the inactive anode produce metal ions and hydrogen ions at a ratio substantially equal to the ratio these ions are consumed at the cathode.

During the plating process, the active anode generates metal ions in the electroplating solution through reaction Me → Me ⁺ + e, but the inert anode is the total current to drive the following reaction: 2H ₂ O → O ₂ + 4H ⁺ + 4e. Use some. On the cathode side, the following two reactions: Me ⁺ + e → Me, and 2H ⁺ + 2e → H ₂ occur simultaneously. By appropriately selecting the amount of current used by the inert anode to match the amount of current consumed by the H ₂ evolution reaction on the cathode, the metal ion generation rate and consumption rate can be tailored to match. . Thus, over the long term, there will be little or no metal ion concentration drifting.

For acid, if the acid produced by, for example, 2H ₂ O → O ₂ + 4H ⁺ + 4e is released into the electroplating solution, the acid production rate and consumption rate will also be balanced.

There is a potential problem of producing a gas (O _{2 in} this case), where the acid production reaction can also affect the plating process by releasing the gas into the anolyte and/or catholyte. In certain embodiments, this gas is vented from the solution, a portion of the electroplating solution is bleed from the system and the acid is replenished by a dosing process. The total amount of acid dosing may be small and will not cause a significant drop in concentration in the concentration of metal ions or other components (eg, boronic acid). Alternatively, as described in U.S. Patent No. 9,816,913, filed December 13, 2011, and U.S. Patent No. 9,816,196, filed April 24, 2013, each of which is incorporated herein by reference in its entirety. Together, by using an oxygen control system, oxygen may be removed from the system.

Approaches to employing an inert anode in the anode loop can be applied in such a way that the active anode and the inactive anode are activated at different times (not simultaneously). For example, if the current efficiency for plating onto a wafer substrate is greater than 50%, the main anode may be used for a number of wafer plating; And during this time, the electroplating solution receives more metal ions than is removed, thus producing a net increase in metal ion concentration. Once the metal ion concentration reaches the trigger level, an inert anode may be used in place of the active anode. During this period of time, the electroplating solution does not accept metal ions and consumes metal ions on the cathode. Thus, there is a net loss of metal ions in the electroplating solution. By alternating between active and inactive anodes, the metal ion concentration may be balanced over a long period of time. This is illustrated in FIG. 5B.

Inert As anode Role assistant Cathode

An example of this approach is illustrated in FIGS. 6A and 6B. In this approach, the inert anode is on the side of the cathode and acts as an anode (passing current) only at certain times, often when the workpieces are not present in the holder. In certain implementations, the inert anode operates occasionally between substrates (ie, after one substrate is removed from the electroplating solution and before the next sequence of substrates is provided to the electroplating solution. In certain embodiments, During the plating process, the inert anode is inert; that is, it does not participate in the electrochemical reaction Therefore, during the plating process, the metal ion generation rate on the anode side is higher than the metal ion consumption rate on the cathode side; that is, into the electroplating solution There is a net addition of metal ions.

At certain times, typically in addition to substrate plating operations (e.g., during wafer handling after plating or during idle time for the electroplating cell), the inert anode is turned on, and The active anode is biased to act as a cathode. At the inert anode, a reaction of 2H ₂ O → O ₂ + 4H ⁺ + 4e takes place, without generating or consuming metal ions. On the anode side (now acting as cathode), the reaction Me ⁺ + e → Me takes place so that the process consumes metal ions from the electroplating solution. Performing this "reverse" plating operation under conditions that now provide high current efficiency of metal plating at the active anode, serving as a cathode, the reactions leading to net metal ion consumption. Reactions may also lead to net hydrogen ion production. These effects tend to balance the production of pure metal ions in the previous wafer plating step. Note that operating the active anode at relatively high plating current tends to produce high current efficiencies for Me ⁺ + e → Me reactions. For certain cobalt electroplating solution compositions, the current efficiency reaches 80 to 90% when the current ranges from about 1 to 2 A (about 1.5 to 3 mA/cm 2 ); Current efficiency reaches 100% when the current is in the range of about 4 to 6 A (5 to 9 mA/cm 2 ).

On certain electroplating tools (e.g., Sabre® family of tools available from Lam Research, Inc., Fremont, CA), one or more auxiliary cathodes are included to help address the end effect (i.e., auxiliary Help to improve the current uniformity across the face of the substrate, especially at the edge of the substrate). In certain embodiments, the auxiliary cathode comprises a noble metal coating (eg Pt). These electrodes can also be used as inert anodes in this approach. Examples of electroplating tools having one or more auxiliary cathodes are described in US Pat. No. 7,854,828, filed Aug. 16, 2006; US Patent No. 8,858,774, filed April 3, 2012; And US Patent Application No. 14/734,882, filed on June 9, 2015, each of which is incorporated herein by reference in its entirety.

In embodiments where the electroplating tool employs an auxiliary cathode as the inert anode, during normal plating, some metal may be plated on the auxiliary cathode. Nevertheless, the disclosed processes will still work beyond this, even after the metal has been stripped from the secondary cathode (by the deplating process), where acid generation takes place on the secondary cathode surface (2H ₂ O → O ₂ + 4H ⁺ + 4e). . At the same time, on the active anode surface (now the cathode), metal ions are consumed through the Me ⁺ + e → Me reaction. Thus, net consumption of metal ions occurs.

assistant With cathode Inert together Anode

An example of this approach is illustrated in FIGS. 7A and 7B. In this approach, both an inert anode and an auxiliary electrode are used. During normal substrate plating, both the inert anode and auxiliary cathode are inactive and are not involved in the plating process. Thus, during this plating process, the metal ion generation rate on the anode side exceeds the metal ion consumption rate on the cathode side, and the electroplating solution experiences net addition of metal ions. In addition to the normal substrate plating process (eg, during substrate processing after plating or during tool idle time), the inert anode is turned on and the auxiliary cathode is biased to act as a cathode. At the inert anode, a reaction of 2H ₂ O → O ₂ + 4H ⁺ + 4e occurs and no metal ions are generated or consumed in the electroplating solution. On the secondary cathode side, a reaction Me ⁺ + e → Me occurs, pulling metal ions from the electroplating solution. By employing an appropriate plating time and current (and thus total coulomb), this supplemental process of net metal ion consumption tends to balance the net metal ions generated during this normal substrate plating process. Over the long term, the two processes (normal substrate plating and supplemental metal ion consumption) tend to stabilize the metal ion concentration in the electroplating solution.

Device

Many device configurations may be used in accordance with the embodiments described herein. One exemplary apparatus includes a clamshell fixture that seals the back side of the wafer from the plating solution while causing the plating to proceed on the side of the wafer. The clamshell fixture may support the wafer, for example, through a seal disposed over the bevel of the wafer, or by vacuum applied to the back side of the wafer, for example with seals applied near the bevel.

The clamshell fixture has to go into the bath to some extent, which allows for good wetting of the plated surface of the wafer. The substrate wet quality is affected by a number of variables including, but not limited to, the clamshell rotation speed, the normal incidence speed, and the angle of the clamshell relative to the surface of the plating bath. These variables and their effects are further discussed in US Pat. No. 6,551,487, which is incorporated herein by reference. In certain embodiments, the electrode rotation rate is about 5 to 125 RPM, the normal incidence rate is about 5 to 300 mm/s, and the angle of the clamshell to the surface of the plating bath is about 1 to 10°. One of the objectives of optimizing these parameters for a particular application is to achieve good wetness by completely displacing air from the wafer surface.

The electrodeposition methods disclosed herein may be described with reference to various electroplating tool devices and may be employed in the context of various electroplating tool devices. An example of a plating apparatus that may be used according to the embodiments of the present specification is a Lam Research Saber tool. Electrodeposition, including substrate immersion, and other methods disclosed herein may be performed on components forming a larger electrodeposition device. 8 is a schematic diagram of a top view of an exemplary electrodeposition device. Electrodeposition apparatus 1400 may include three separate electroplating modules 1402, 1404, and 1406. Electrodeposition apparatus 1400 may also include three separate modules 1412, 1414, and 1416 configured for various process operations. For example, in some embodiments, the one or more modules 1412, 1414, and 1416 may be a spin rinse drying (SRD) module. In other embodiments, the one or more modules 1412, 1414, and 1416 may be post-electrofill modules (PEMs), each processed by one of the electroplating modules 1402, 1404, and 1406. Thereafter, it is configured to perform functions such as edge bevel removal, backside etching and acid cleaning of the substrates.

The electrodeposition apparatus 1400 includes a central electrodeposition chamber 1424. The central electrodeposition chamber 1424 is a chamber that holds the chemical solution used as the electroplating solution within the electroplating modules 1402, 1404, and 1406. The electrodeposition apparatus 1400 also includes a dosing system 1426 that may store and deliver additives to the electroplating solution. The chemical dilution module 1422 may store or mix chemicals to be used as an etchant. The filter and pumping unit 1428 may filter the electroplating solution for the central electrodeposition chamber 1424 and may pump to the electroplating modules.

The system controller 1430 provides the electronic control and interface control required to operate the electrodeposition device 1400. The system controller 1430 (which may include one or more physical or logical controllers) controls some or all of the attributes of the electroplating apparatus 1400. System controller 1430 typically includes one or more memory devices and one or more processes. The processor may include a central processing unit (CPU) or computer, analog and/or digital input/output connections, stepper motor controller boards, and other components. Instructions for implementing appropriate control operations as described herein may be executed on a processor. These instructions may be stored on memory devices associated with the system controller 1430 or they may be provided over a network. In certain embodiments, system controller 1430 executes system control software.

The system logic (e.g., control software) of the electrodeposition apparatus 1400 includes timing, mixture of electrolyte components (including concentration of one or more electrolyte components), inlet pressure, plating cell pressure, plating cell temperature, substrate temperature, and substrate. And instructions for controlling current and potential applied to any other electrodes, substrate position, substrate rotation, and other parameters of a particular process performed by the electrodeposition apparatus 1400. The system control logic may also include instructions for electroplating under conditions tailored to suit low copper concentration electrolytes. For example, the system control logic may be configured to provide a relatively low current density during the bottom-up fill stage and/or a higher current density during the overburden stage. The control logic may also be configured to provide certain levels of mass transfer to the wafer surface during plating. For example, the control logic may be configured to control the flow of electrolyte to ensure sufficient mass transfer to the wafer during plating so that the substrate does not face depleted copper conditions. In certain embodiments, the control logic may have different levels of mass transfer at different stages of the plating process (e.g., a higher mass transfer during the bottom-up fill stage than during the overburden stage, or a bottom-up than during the overburden stage It may also operate to provide a lower mass transfer during the filling stage. Further, the system control logic may be configured to maintain the concentration of one or more electrolyte components within any ranges disclosed herein. As a specific example, the system control logic may be designed or configured to maintain a concentration of copper cations of about 1 to 10 g/l. System control logic may be configured in any suitable manner. For example, various process tool component sub-routines or control objects may be written to control the operation of process tool components used to perform various process tool processes. The system control software may be coded in any suitable computer readable programming language. The logic may also be implemented as hardware of a programmable logic device (eg, an FPGA), an ASIC, or other suitable vehicle.

In some embodiments, the system control logic includes input/output control (IOC) sequencing instructions to control the various parameters described above. For example, each phase of the electroplating process may include one or more instructions for execution by system controller 1430. Instructions for setting process conditions for the immersion process phase may be included in the corresponding immersion recipe phase. In some embodiments, the electroplating recipe phases may be arranged sequentially such that all instructions for the electroplating process phase are executed concurrently with this process phase.

The control logic may be divided into various components such as programs or sections of programs in some embodiments. Examples of logic components for this purpose include a substrate positioning component, an electrolyte composition control component, a pressure control component, a heater control component, and a potential/current power supply control component.

In some embodiments, there may be a user interface associated with the system controller 1430. The user interface may include a display screen, graphical software displays of device and/or process states, and user input devices such as pointing devices, keyboards, touch screens, microphones, and the like.

In some embodiments, parameters adjusted by system controller 1430 may be related to process conditions. Non-limiting examples include bath conditions (temperature, composition, and flow rate), substrate position at various stages (rotation rate, linear (vertical) speed, angle from horizontal), and the like. These parameters may be provided to the user in the form of a recipe, which may be input using a user interface.

Signals for monitoring the process may be provided by analog and/or digital input connections of the system controller 1430 from various process tool sensors. Signals for controlling the process may be output to the analog and digital output connections of the process tool. Non-limiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (eg manometers), thermocouples, optical position sensors, and the like. Appropriately programmed feedback and control algorithms may use data from these sensors to maintain process conditions.

In one embodiment, the instructions may include instructions for inserting a substrate into a wafer holder, an instruction for tilting the substrate, an instruction for biasing the substrate during immersion, and an instruction for electrodepositing a copper-containing structure onto the substrate.

The hand-off tool 1440 may select a substrate from a substrate cassette such as cassette 1442 or cassette 1444. Cassettes 1442 or 1444 may be front opening unified pods (FOUPs). The FOUP is an enclosure designed to reliably and safely hold substrates in a controlled atmosphere and allow the substrates to be removed for processing or measurement by tools equipped with appropriate load ports and robotic handling systems. The hand-off tool 1440 may hold the substrate using a vacuum attachment or some other attachment mechanism.

The hand-off tool 1440 may interface with a wafer handling station 1432, cassettes 1442 or 1444, a transfer station 1450, or an aligner 1448. From the transfer station 1450, a hand-off tool 1446 may obtain access to the substrate. Transfer station 1450 may be a slot or location that may transfer substrates from hand-off tools 1440 and 1446 and to hand-off tools 1440 and 1446 without passing through aligner 1448. However, in some embodiments, to ensure that the substrate is properly aligned on the hand-off tool 1446 for precise transfer to the electroplating module, the hand-off tool 1446 is used with the aligner 1448 and the substrate. You can also sort. The hand-off tool 1446 may also transfer the substrate to one of the electroplating modules 1402, 1404, or 1406 configured for various process operations or to one of three separate modules 1412, 1414, and 1416. have.

Examples of process operation according to the methods described above are: (1) electrodepositing copper onto a substrate to form a copper-containing structure in the electroplating module 1404 and (2) the substrate at the SRD in the module 1412. Rinse and dry, and (3) performing edge bevel removal within module 1414 may proceed.

An apparatus configured to enable effective cycling of substrates through sequential plating, rinsing, drying and PEM process operations may be useful in implementations for use in a manufacturing atmosphere. To achieve this, the module 1412 can be configured as a spin rinse dryer and an edge bevel removal chamber. Using this module 1412, the substrate only has to be transferred between the electroplating module 1404 and the module 1412 for copper plating and EBR operations.

In some implementations, a controller (eg, system controller 1430) is part of a system, which may be part of the examples described above. The controller may include control logic or software and/or may execute instructions provided from another source. Such systems may include semiconductor processing equipment, including processing tool or tools, chamber or chambers, platform or platforms for processing, and/or specific processing components (wafer pedestal, gas flow system, etc.) . These systems may be integrated into the electronics for controlling their steps prior to, during and after processing of a semiconductor wafer or substrate. Electronics may be referred to as a “controller” that may control the system or various components or sub-parts of the systems. The controller can, depending on the processing requirements and/or the type of system, the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings. , Radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and step settings, tools and other transfer tools and/or It may be programmed to control any of the processes disclosed herein, including wafer transfers into and out of loadlocks connected or interfaced with a particular system.

Generally speaking, the controller receives instructions, issues instructions, controls the operations described above, enables cleaning steps, enables endpoint measurements, instrumentation, etc. Various integrated circuits, logic, It may be defined as an electronic device with memory and/or software. Integrated circuits are chips in the form of firmware that store program instructions, digital signal processors (DSP), chips that are defined as application specific integrated circuits (ASICs) and/or execute program instructions (e.g., software). It may include one or more microprocessors, or microcontrollers. Program instructions may be instructions that are passed to a controller or to a system in the form of various individual settings (or program files) that specify step parameters for executing a specific process on or on a semiconductor wafer. In some embodiments, the step parameters are processed to achieve one or more processing steps during fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of the wafer. It may be part of a recipe prescribed by the engineers.

The controller may be coupled to, or be part of, a computer, which in some implementations may be integrated into the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or part of a fab host computer system that may enable remote access of wafer processing. The computer monitors the current progress of manufacturing steps, examines the history of past manufacturing steps, examines trends or performance metrics from multiple manufacturing steps, changes parameters of current processing, and steps processing steps following the current processing. You can configure, or enable remote access to the system to start a new process. In some examples, a remote computer (eg, a server) can provide process recipes to the system over a local network or a network that may include the Internet. The remote computer may include a user interface that enables programming or input of parameters and/or settings to be subsequently passed from the remote computer to the system. In some examples, the controller receives instructions in the form of data, specifying parameters for each of the process steps to be performed during one or more steps. It should be understood that these parameters may be specific to the type of tool the controller is configured to control or interface with and the type of process to be performed. Thus, as noted above, the controller may be distributed, for example, by including one or more individual controllers that are networked with each other and cooperate together for a common purpose, eg, for the processes and controls described herein. An example of a decentralized controller for this purpose is one or more integrated circuits on a chamber that communicate with one or more remotely located integrated circuits (e.g., at the platform level or as part of a remote computer) that are combined to control a process on the chamber. It can be circuits.

Without limitation, exemplary systems include plasma etch chamber or module, deposition chamber or module, spin-rinse chamber or module, metal plating chamber or module, cleaning chamber or module, bevel edge etch chamber or module, physical vapor deposition (PVD). Chamber or module, chemical vapor deposition (CVD) chamber or module, atomic layer deposition (ALD) chamber or module, atomic layer etch (ALE) chamber or module, ion implantation chamber or module, track chamber or module, and semiconductor It may include any other semiconductor processing systems that may be used or associated with the fabrication and/or fabrication of wafers.

As described above, depending on the process step or steps to be performed by the tool, the controller is used in material transfer to move containers of wafers to/from tool locations and/or load ports within a semiconductor fabrication plant. May communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, main computer, another controller or tools .

An alternative embodiment of an electrodeposition apparatus 1500 is schematically illustrated in FIG. 9. In this embodiment, the electrodeposition apparatus 1500 has a set of electroplating cells 1507, each of which comprises a pair or a plurality of "duet" configuration electroplating baths. In addition to the electroplating itself , the electrodeposition apparatus 1500 includes various other electroplating related processes and sub-steps, such as, for example, spin-rinsing, metal and silicon wet etching, electroless deposition, pre-wet (pre -wetting) and pre-chemical treatment, reduction, annealing, photoresist stripping, and surface pre-activation may also be performed. In FIG. 9 an electrodeposition device 1500 viewed from top to bottom is schematically shown, and a single level or "floor" is revealed in the drawing, but such devices, for example Lam Sabre ^TM 3D tools, have two or more levels on top of each other. It is readily understood by those skilled in the art that they can be "stacked", and that each level potentially has the same or different types of processing stations.

Referring once again to FIG. 9, the substrates 1506 to be electroplated are generally fed to the electrodeposition apparatus 1500 via a front end loading FOUP 1501, in this example, from the FOUP to the front-end robot 1502. It is moved to the main substrate processing area of the electrodeposition apparatus 1500 via the robot 1502 which has accessible stations-in this example two front-end accessible stations 1504 and also two front-end access. It is possible to retract and move the substrate 1506 driven by the spindle 1503 in multiple dimensions from one of the possible stations 1508 shown-from one station to another. These front-end accessible stations 1504, 1508 may include, for example, pre-treatment stations and spin rinse drying (SRD) stations. The side-to-side lateral movement of the front-end robot 1502 is achieved by utilizing the robot track 1502a. Each of the substrates 1506 may be held by a cup/cone assembly (not shown) driven by a spindle 1503 connected to a motor (not shown), and the motor may be attached to a mounting bracket 1509. Also, in this example, four "duet-type" electroplating cells 1507 are shown for a total of eight electroplating cells 1507. Electroplating cells 1507 may be used to electroplate copper for a copper containing structure and to electroplat a solder material for a solder structure. A system controller (not shown) may be coupled to the electrodeposition device 1500 to control some or all of the characteristics of the electrodeposition device 1500. The system controller may be programmed or otherwise configured to execute instructions according to the processes previously described herein.

The electroplating apparatus/methods described above herein may be used in conjunction with lithographic patterning tools or processes, for example, for the manufacture or fabrication of semiconductor devices, displays, LEDs, photovoltaic panels, etc. . In general, although not necessarily, these tools/processes will be performed and used together in a common manufacturing facility. Lithographic patterning of a film is generally performed with the following steps, each of which is enabled using a number of possible tools: (1) a spin-on tool or a spray-on tool. Applying a photoresist onto a workpiece, ie, a substrate using; (2) curing the photoresist using a hot plate or furnace or UV tool; (3) exposing the photoresist to visible or UV or x-ray light using a tool such as a wafer stepper; (4) developing the resist to pattern the resist by selectively removing the resist using a tool such as a wet bench; (5) transferring the resist pattern into the underlying film or workpiece by using a dry or plasma secondary etching tool; And (6) some or all of the steps of removing the resist using a tool such as an RF or microwave plasma resist stripper.

When numerical ranges are presented the endpoints of these ranges are not limited to exact values having significantly more digits than those used. Unless otherwise specified, endpoints include variability to some extent in accordance with all objectives of this disclosure. For example, the endpoints may be interpreted to include values within +/- 10% of the aforementioned value.

It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and because many variations are possible, these specific embodiments or examples are not to be regarded in a limiting sense. Certain routines or methods described herein may represent one or more of any number of processing strategies. As such, the various operations illustrated may be performed in the illustrated order, in different orders, simultaneously, or may be omitted in some cases. Similarly, the order of the processes described above may be varied.

The subject matter of this disclosure is all novel and non-obvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, actions, and/or attributes disclosed herein, as well as these Includes any and all equivalents of.

Claims (22)

A method of electroplating a metal on a substrate during manufacture of a device, comprising:
(a) (i) a cathode portion configured to hold the substrate while electroplating metal on the substrate,
(ii) an electroplating solution containing ions of the metal,
(iii) an active anode, and
(iv) providing an electroplating solution to an electroplating system comprising an inert anode;
(b) providing the active anode with a first fraction of total current to electroplat the metal on the substrate; And
(c) providing a second fraction of the total current to the inert anode for electroplating the metal on the substrate,
The first fraction and the second fraction respectively approximate fractions of metal plating on the substrate and one or more parasitic reactions, and
The method of electroplating, wherein providing the first fraction of the total current and providing the second fraction of the total current causes the metal to be electroplated onto the substrate. The method of claim 1,
The method of electroplating, wherein the metal is cobalt, and the active anode comprises cobalt. The method of claim 1,
The method of electroplating, wherein the metal is copper and the active anode comprises copper. The method according to any one of claims 1 to 3,
The method of electroplating, wherein the one or more parasitic reactions include hydrogen ion reduction. The method according to any one of claims 1 to 4,
The method of electroplating, wherein the step of providing the second fraction of the total current to the inert anode also causes a hydrogen ion generation reaction that does not generate metal cations. The method according to any one of claims 1 to 5,
The electroplating solution comprises cobalt ions, acids, borate ions, and organic plating additives. The method according to any one of claims 1 to 6,
The electroplating system further comprises an ion transfer separator configured to provide a path for ionic communication between the anode portion and the cathode portion and between the anode portion and the electroplating solution of the cathode portion. Electroplating method. The method of claim 7,
The method of electroplating, wherein the ion transfer separator comprises a cation exchange membrane. The method according to any one of claims 1 to 8,
The electroplating method, wherein the first fraction of the total current and the second fraction of the total current are provided simultaneously. The method according to any one of claims 1 to 9,
The electroplating cell further comprises one or more auxiliary electrode chambers each including an electrode. The method of claim 10,
And providing at least a portion of the second fraction of the total current to the electrodes of the one or more auxiliary electrode chambers while the metal is not electroplating on the substrate. A system for electroplating metal on a substrate during manufacture of a device, comprising:
(a) an electroplating cell comprising an anode portion and a cathode portion, and configured to hold the substrate to the cathode portion while electroplating metal on the substrate;
(b) an active anode comprising the metal;
(c) an inert anode; And
(d) as a controller,
(i) providing a first fraction of the total current to the active anode to electroplat the metal on the substrate, and
(ii) the controller comprising instructions for providing a second fraction of the total current to the inert anode to electroplat the metal on the substrate,
Wherein the first fraction and the second fraction respectively approximate fractions of metal plating in the substrate and one or more parasitic reactions. The method of claim 12,
The electroplating system further comprises an ion transfer separator configured to provide a path for ion communication between the anode portion and the cathode portion and between the anode portion and the electroplating solution of the cathode portion. The method of claim 13,
Wherein the ion transfer separator comprises a cation exchange membrane. The method according to any one of claims 12 to 14,
Wherein the electroplating cell further comprises one or more auxiliary electrode chambers. The method of claim 15,
The electroplating system, wherein the one or more one or more auxiliary electrode chambers comprise one or more auxiliary cathodes. The method of claim 16,
The controller further comprises instructions for providing at least a portion of the second fraction of the total current to the one or more auxiliary cathodes while the metal is not electroplating on the substrate. The method according to any one of claims 1 to 17,
The metal is cobalt, electroplating system. The method according to any one of claims 12 to 18,
The electroplating system, wherein the metal is copper. The method according to any one of claims 12 to 19,
The controller further comprising instructions for simultaneously providing the first fraction of the total current and the second fraction of the total current. A method of electroplating a metal on a substrate during manufacture of a device, comprising:
(a) (i) a cathode portion configured to hold the substrate while electroplating metal on the substrate,
(ii) an electroplating solution containing ions of the metal,
(iii) an active anode, and
(iv) providing an electroplating solution to an electroplating system comprising an inert anode;
(b) providing the active anode with a first fraction of the total current to electroplat the metal on the substrate; And
(c) providing a second fraction of the total current to the inert anode for electroplating the metal on the substrate,
The first fraction and the second fraction approximate the plating current efficiency of metal plating on the substrate, and
The method of electroplating, wherein providing the first fraction of the total current and providing the second fraction of the total current causes the metal to be electroplated onto the substrate. A system for electroplating metal on a substrate during manufacture of a device, comprising:
(a) an electroplating cell comprising an anode portion and a cathode portion, and configured to hold the substrate to the cathode portion while electroplating metal on the substrate;
(b) an active anode comprising the metal;
(c) an inert anode; And
(d) as a controller,
(i) providing a first fraction of the total current to the active anode to electroplat the metal on the substrate, and
(ii) the controller comprising instructions for providing a second fraction of the total current to the inert anode to electroplat the metal on the substrate,
The first fraction and the second fraction approximate plating current efficiency of the metal plating on the substrate.

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