Improving substrate wettability for plating operations

Abstract

Various embodiments include methods and apparatus for wetting a substrate prior to an electrochemical deposition process. In one embodiment, a method for controlling substrate wettability includes: placing a substrate in a pretreatment chamber, controlling the environment of the pretreatment chamber to wet the substrate surface; and placing the substrate in a plating tank. Other methods and systems are also disclosed.

Description

[0001] Priority claim

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 664,938, filed on April 30, 2018, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The subject matter disclosed herein relates to processing various types of substrates (such as silicon wafers or other elemental or compound wafers, or generally referred to as "wafers") that have poor wettability due to other processing steps prior to plating. Specifically, the disclosed subject matter improves wetting of substrates during immersion in a plating bath and improves performance during electrochemical plating processes on substrates. Background Art

[0004] Electrochemical deposition processes are commonly used for metallization of integrated circuits. In a variety of processes, the deposition process involves depositing metal lines into trenches and vias that have been preformed in a previously formed dielectric layer. In this dependent process, a thin adherent metal diffusion barrier film is pre-deposited onto the surface, typically using a physical vapor deposition (PVD) or chemical vapor deposition (CVD) process. Depending on the target metal film, a subsequent metal seed layer will be deposited on top of the barrier film. Next, the features (vias and trenches) are electrochemically filled with the target metal by an electrochemical deposition process.

[0005] However, the performance of electrochemical deposition onto a substrate is affected by many factors. For example, the bath composition (including both the concentration of inorganic components and the concentration of additives) plays an important role in ensuring void-free gap filling. The manner in which the substrate enters the plating solution (e.g., the time required for the cathode / substrate to be completely immersed in the plating solution, the angle at which the cathode / substrate enters the solution, the rotation speed of the cathode / substrate during immersion, etc.) and the current and voltage applied to the substrate may play an important role in the gap filling quality and gap filling uniformity across the substrate.

[0006] A number of aspects regarding the initial immersion of the cathode / substrate into the plating solution are known to those skilled in the art. One aspect that plays an important role is the wettability of the substrate to the plating bath during entry. For example, without proper wetting, gas bubbles may adhere to certain areas of the substrate surface, and subsequent electrodeposition in the areas affected by the bubbles may be difficult to achieve due to electrical discontinuities. The end result is missing plating in these areas. Defects associated with this poor wettability are often referred to as "missing metal" defects. This missing metal defect often creates a "killer defect" for areas of the substrate containing active components. For example, Figure 1A and 1B A typical defect diagram showing poor substrate wetting under the prior art method. Figure 1A and 1BThe darker areas in the graph represent defects with a high area concentration. Figures 2A to 2C Typical defect shapes on the substrate surface caused by poor wetting are shown with gradually decreasing fields of view (FOV). Figure 2A Displays defects at a FOV of about 98μm, Figure 2B The defect is shown at a FOV of about 11.25 μm, while Figure 2C Defects are shown at a FOV of approximately 3 μm.

[0007] As mentioned above, in an electrochemical plating process, a thin, adherent metal diffusion barrier film is typically pre-deposited onto the surface by utilizing, for example, physical vapor deposition (PVD) or chemical vapor deposition (CVD) techniques. Depending on the target metal film, a metal seed layer may then be deposited on top of the barrier film. Typically, a time difference (Δt, referred to as the "waiting time") is created from the time the barrier and seed layers are deposited onto the substrate to the time the substrate is ready for electrochemical deposition. During the waiting time, the surface conditions of the substrate are expected to change over time. One of the most widely noticed surface changes is oxidation of the metal layer on the substrate. Oxidation of the surface metal increases the sheet resistance of the seed layer, which in turn makes it more difficult to plate uniformly on the seed layer due to a stronger terminal effect. The oxide layer changes the adsorption behavior of additives on the seed layer and may cause a variety of plating problems. The oxide layer also changes the wetting behavior of the substrate during immersion. If the oxide is not reduced to metal before plating, it will dissolve into the plating bath, which may then cause seed layer loss and other problems known to those skilled in the art. In addition, the oxidation of the metal seed layer is usually non-uniform across the substrate. Therefore, the non-uniformity is usually strongly dependent on the waiting time. Therefore, substrate oxidation during the waiting period can cause changes in the performance of the plating process, and oxidation is usually detrimental to the plating process.

[0008] In order to eliminate or reduce the impact of waiting time and ensure process performance, various methods have been used in the semiconductor and related industries to solve the problem of seed layer oxidation. One method is to place the substrate in an environmentally controlled front opening wafer transport box (FOUP) after forming the seed and before plating. In this example, the FOUP is usually filled with nitrogen (N2) to prevent oxygen (O2) from reaching the substrate, thereby O2 oxidizing the seed, as shown in Figure 3A.

[0009] Fig. 3 A shows a method 300 of the prior art, which is used to reduce oxidation on the plating equipment, followed by multiple deposition, cleaning and post-annealing operations. Method 300 shows the operation of the seed substrate entering in a FOUP, which includes an N2 environment. Then, the substrate is transferred to a plating tank for electrochemical deposition. After completing the electrochemical deposition, the substrate is then transferred to the plating back chamber for cleaning and drying. In subsequent operations, the substrate is then transferred to an annealing chamber for post-annealing. Once all operations shown are completed, the substrate is then moved back to the FOUP.

[0010] Referring now to FIG. 3B , a second prior art method 310 for solving the seed layer oxidation problem is to reduce the surface oxide in a hydrogen (H2) environment at an elevated temperature. Method 310 shows the operation of an incoming seed substrate in a FOUP. The substrate is transferred from the FOUP to a pre-plating annealing process, where the substrate is subjected to an annealing process in a forming gas with H2. The substrate is then transferred to a plating tank for electrochemical deposition. After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber for cleaning and drying. In subsequent operations, the substrate is then transferred to an annealing chamber for a post-annealing process. Once all operations shown are completed, the substrate is then moved back to the FOUP. This H2-based process is typically referred to as a pre-annealing process and needs to be performed immediately prior to the plating process.

[0011] FIG. 3C shows a third method 330 for solving the problem of seed layer oxidation in the prior art. The third method 300 uses hydrogen (H) radicals to reduce surface oxides in an environment based on H2 plasma. The method 330 shows the operation of the incoming seed substrate in a FOUP. The substrate is transferred from the FOUP to a pretreatment chamber, where the substrate is placed under vacuum in an environment based on H2 plasma at an elevated temperature. Then, the substrate is transferred to a plating tank for electrochemical deposition. After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber for cleaning and drying. In subsequent operations, the substrate is then transferred to an annealing chamber for a post-annealing process. Once all operations shown are completed, the substrate is then moved back to the FOUP. This H2 plasma-based process is generally referred to as a pre-annealing process, and it needs to be performed immediately before the plating process. Similar to the pre-annealing process, this H2 plasma-based process is typically performed immediately before the plating process. However, compared to the pre-annealing process discussed with reference to FIGS. 3A and 3B, this process can be performed at a significantly lower temperature. As reported in the literature and known to those skilled in the art, H2 plasma based processes are also capable of cleaning surface layers and removing many impurities in the seed layer.

[0012] However, in some applications, it has been observed that the above-mentioned prior art methods and processes for preventing oxidation or reducing formed metal oxides to metal may cause other problems in the subsequent plating process. For example, it has been found that placing the substrate in an N2-filled FOUP for a long time is generally effective in preventing oxidation from occurring. However, it has also been found that the substrate may become very difficult to wet during the subsequent plating process. Similarly, it has been found that the pre-annealing process or pre-reduction process in the H2 plasma-based process can deteriorate the wettability of the seed substrate during plating, thereby causing skipping defects during plating. Without proper treatment, the above-mentioned processes and methods for controlling, reducing or eliminating surface metal oxides cannot be successfully performed.

[0013] The information described in this section is provided to present a context for the subject matter described below to those skilled in the art and should not be construed as admitted prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A and 1B A typical image showing defects caused by poor substrate wetting in the prior art;

[0015] Figures 2A to 2C The typical defect shapes on the substrate surface caused by poor wetting treatment in the prior art are shown in different fields of view (FOV);

[0016] 3A to 3C show examples of various methods that have been used in the prior art to reduce oxidation on plating equipment, which are followed by various deposition, cleaning and post-annealing operations;

[0017] Figures 4A to 4D showing examples of various techniques for reducing or eliminating oxidation and increasing wettability on plating equipment according to various embodiments disclosed herein, at least some of which are followed by various deposition, cleaning, and post-annealing operations;

[0018] Figure 5 Examples of defect graphs showing typical results from applying one or more of the various embodiments disclosed herein;

[0019] Fig. 6A An exemplary embodiment of environmental control of a substrate in a vacuum / atmosphere conversion module is shown;

[0020] Figure 6B An exemplary embodiment of environmental control of a substrate in a stop module is shown;

[0021] Fig. 7A is an illustration of a prior art process in which H2O molecules previously adsorbed on a substrate surface are stripped or substantially stripped from a metal layer; and

[0022] Figure 7B H2O molecules are shown adsorbed on the surface 710 of the substrate. Specific implementation plan

[0023] The disclosed subject matter will now be described in detail with reference to several general and specific embodiments shown in the various figures of the drawings. In the following description, many specific details are set forth to provide a thorough understanding of the disclosed subject matter. However, it will be apparent to those skilled in the art that the disclosed subject matter may be practiced without some or all of these specific details. In other cases, well-known process steps or structures are not described in detail to avoid obscuring the disclosed subject matter.

[0024] The disclosed subject matter contained herein describes various embodiments for improving substrate wettability. However, as described above, it has been found that various substrate entry methods of the prior art have limited improvement in substrate wettability. Therefore, these prior art processes only partially improve the problem of missed plating defects caused by poor wetting.

[0025] As disclosed herein, by "wetting" the surface of the substrate substantially immediately prior to a subsequent electrochemical plating process (see below). Figure 7B The adsorption mechanism and the accompanying redundant description) can more fully solve the substrate wettability problem. Upon reading and understanding the disclosure provided herein, those skilled in the art will know that the various embodiments disclosed herein are different from the pre-wetting method of the prior art.

[0026] For example, for some electrochemical plating applications, the substrate cannot be fully wetted. Otherwise, the features on the substrate may be filled with deionized (DI) water through a pre-wetting process. The subsequent electrochemical plating process in the feature can then be affected because DI water occupies (e.g., fills or partially fills) some or all features. The following disclosed subject matter helps to produce a uniform or substantially uniform wetting surface, so that good wetting behavior is arranged during plating, without filling features with excessive DI, thereby improving wettability and not reducing the performance of subsequent plating processes.

[0027] In various embodiments, the natural wetting process of the substrate surface before the plating process is disclosed. Generally speaking, natural wetting relates to the surface of the substrate moistened by the moisture in the environment of the plating tool. Natural wetting can be implemented in the following manner, such as before the plating is carried out in the plating equipment before the plating tank or in the plating tank itself in various positions (such as, substantially immediately before the plating), "waiting step" is introduced into the processing procedure. The time period in the waiting step depends on many factors, such as the nature of making the substrate such as a hydrophilic or hydrophobic substrate (including any film formed thereon), the relative humidity of the "waiting volume (waiting volume)", and other factors known or knowable to those skilled in the art. Once these factors are known, those skilled in the art can then determine the time period of the waiting step (and other factors, such as the relative humidity, temperature, etc. in the partial pressure of H2O vapor or the waiting volume) based on thermodynamics and chemical adsorption principles.

[0028] For example, in natural wetting, the substrate may wait on the end effector of a robot arm before placing the substrate in a plating tank; wait in a FOUP exposed to air after other processing procedures (such as pre-annealing, treatment in H2 plasma, etc.); and / or wait in a processing module exposed to air on a stacking station before the plating tank. As described above, the required residence time depends at least in part on the relative humidity and other factors in the environment at the corresponding location. However, depending on the implementation, the waiting time using this natural wetting method may be significantly sufficient to cause backlogs and potential production capacity problems on the plating equipment, and sometimes even cause difficulties in the sequencing of substrate operations. On the other hand, it has been found that waiting in a plating tank is very feasible, and it has been found that a waiting time of about 5 seconds to about 30 seconds can completely wet the substrate, thereby completely or substantially alleviating the poor wettability of the original substrate described in the prior art.

[0029] In various embodiments, accelerated / controlled wetting of the substrate surface prior to the plating process is also disclosed. Generally, for the accelerated / controlled wetting embodiments, the substrate may be exposed to a controlled environment.

[0030] For example, because the wetting process depends on the relative humidity inside the plating equipment, the metal surface is by the O in the environment, the possibility of oxidation and the substrate absorbs the required time of moisture from the environment, so in various embodiments, the substrate can be exposed to a controlled environment. This controlled environment can be, for example, an oxygen-free or oxygen-regulated environment to prevent or reduce excessive surface oxidation (see, for example, Figure 4A ). Also refer to Figures 4A to 4DOne or more of the accompanying drawings in the drawings, possible embodiments include but are not limited to: (a) a substrate exposed to humidified N2 provided by a nozzle in a plating tank; (b) a substrate exposed to humidified N2 in a stacking / parking station before a plating module; (c) a substrate exposed to humidified N2 in a FOUP; (d) a substrate exposed to humidified N2 in any desired processing module before a plating module; (e) a substrate exposed to water vapor in any desired processing module (including but not limited to a vacuum module, a vacuum / atmosphere conversion module, or an atmosphere module) before a plating module; and / or (f) any of the above embodiments performed in a separate module (rather than on a plating device). Detailed descriptions are provided below for each of these and more processes. Although the various embodiments disclosed herein may mean that the substrate is located in a FOUP during various operating stages, the substrate may also be located in another environment, such as various types of substrate stations, substrate boxes, substrate holding positions, and other types of positions and equipment. Therefore, such a type of position (which may include, for example, N2, DI, and / or an oxygen-free environment) may be referred to herein as a "substrate environment". Furthermore, although various embodiments are described with reference to plating operations, the disclosed subject matter is not limited thereto and the embodiments are applicable to a variety of different methods, processes, and operations.

[0031] For example, now refer to Figure 4A , which shows an exemplary embodiment of a method 400 for reducing or eliminating oxidation and simultaneously or substantially simultaneously increasing wettability of a substrate in a plating apparatus. The method 400 shows an operation 401, wherein an incoming seed substrate (a substrate having a metal seed layer formed thereon) is in a substantially oxygen-free, regulated DI humidified FOUP environment, wherein the FOUP includes an N2 environment.

[0032] A regulated DI humidified FOUP environment refers to an environment having, for example, a controlled relative humidity (RH) range of about 20% to about 100%. The substrate may be maintained in this environment for a variety of times based on factors such as upstream processes, process requirements, tool availability, desired substrate productivity, and a variety of other factors. Thus, for a given process, the time in a regulated DI humidified FOUP environment may be from a few seconds to several hours long. Therefore, the RH ranges and times given are merely examples and may vary significantly for a particular process. In addition, as described above, in the various embodiments described herein, those skilled in the art will recognize that the substrate may be in a variety of environments (e.g., substrate environments) other than a FOUP. Therefore, only the environment within a FOUP is provided as an example of an environment that may be generated.

[0033] Continue to refer Figure 4A, in operation 403, the substrate is then transferred to a plating tank for electrochemical deposition. After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber in operation 405 for the substrate to be cleaned and dried. In a subsequent operation 407, the substrate is then transferred to an annealing chamber for a post-annealing process. In various examples, the post-annealing process may include annealing the substrate in a range of about 30° C. to about 400° C. for about 30 seconds to about 600 seconds, with a cooling time of about 30 seconds to about 600 seconds. However, these times and temperatures are provided only as examples, and both times and temperatures may vary significantly for a particular process. Once all operations shown are completed, the substrate is then moved back to the FOUP in operation 409.

[0034] At Figure 4B , which shows another exemplary embodiment of a method 410 for reducing or eliminating oxidation and simultaneously or substantially simultaneously increasing the wettability of a substrate in a plating apparatus. Method 410 illustrates operation 411, wherein an incoming seed substrate is located in a FOUP, wherein the FOUP includes an N2-based environment. At operation 413, a substrate wetting step is performed on the substrate in accordance with various embodiments described herein. At operation 415, the substrate is then transferred to a plating tank for electrochemical deposition. After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber in operation 417 so that the substrate is cleaned and dried. In a subsequent operation 419, the substrate is then transferred to an annealing chamber for a post-annealing process. The post-annealing process may be similar to that described in reference to FIG. Figure 4A The parameters given are the same or similar. Once all operations shown are completed, the substrate is then moved back to the FOUP in operation 421.

[0035] exist Figure 4C, another exemplary embodiment of a method 430 for reducing or eliminating oxidation and simultaneously or substantially simultaneously increasing the wettability of a substrate in a plating apparatus is shown. Method 430 shows operation 431, wherein an incoming seed substrate is located in a FOUP. In some embodiments, the FOUP does not necessarily include an N2-based environment. In other embodiments, the FOUP includes an N2-based environment. In operation 433, the substrate is subjected to a pre-plating annealing process in a mixed gas with hydrogen (H2). In various examples, the pre-annealing process may include annealing the substrate for about 30 seconds to about 600 seconds at a temperature in the range of about 30°C to about 400°C, with a cooling time of about 30 seconds to about 600 seconds. However, these times and temperatures are provided only as examples, and both times and / or temperatures may vary significantly for a particular process. In addition, as described above, the pre-annealing process may include a mixed gas of H2, which may be mixed with N2. In an embodiment, H2 may be mixed with N2 and helium (He). The H2 flow percentage of the total mixed gas may be about, for example, about 4% or less. However, this H2 flow percentage is provided as an example only and may vary significantly for a particular process. At operation 435, the substrate is subjected to a substrate wetting step according to various embodiments described herein. At operation 437, the substrate is then transferred to a plating tank for electrochemical deposition. After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber at operation 439 to clean and dry the substrate. In a subsequent operation 441, the substrate is then transferred to an annealing chamber for a post-annealing process. The post-annealing process may be similar to that described in reference to FIG. Figure 4A The parameters given are the same or similar. Once all operations shown are completed, the substrate is then moved back to the FOUP in operation 443.

[0036] Reference Figure 4D, another exemplary embodiment of a method 450 for reducing or eliminating oxidation and simultaneously or substantially simultaneously increasing the wettability of a substrate in a plating apparatus is shown. The method 450 shows an operation 451, wherein the incoming seed substrate is located in a FOUP. In some embodiments, the FOUP does not necessarily include an N2-based environment. In other embodiments, the FOUP includes an N2-based environment. In operation 453, the substrate is transferred to a pretreatment chamber with H2 plasma at a vacuum and elevated temperature. In various embodiments, the vacuum degree may be from about 0.1 torr to about 5 torr. The elevated temperature may range, for example, from about 30°C to about 400°C to enhance the formation of free radicals associated with the plasma, thereby increasing the substrate pretreatment efficiency. In various examples, the processing time in the pretreatment chamber may be, for example, from about 30 seconds to about 600 seconds. However, these vacuum degrees, temperatures, and times are provided only as examples, and for a particular process, one or more of the vacuum degrees, temperatures, and times may vary significantly. In operation 455, a substrate wetting step is performed on the substrate according to various embodiments described herein. At operation 457, the substrate is then transferred to a plating tank for electrochemical deposition.

[0037] After the electrochemical deposition is completed, the substrate is then transferred to a post-plating chamber at operation 459 for cleaning and drying. In subsequent operation 461, the substrate is then transferred to an annealing chamber for a post-annealing process. The post-annealing process can be similar to that described in reference Figure 4A The parameters given are the same or similar. Once all operations shown are completed, the substrate is then moved back to the FOUP in operation 463.

[0038] Figure 5 An example defect map showing typical results after applying one or more embodiments disclosed herein (e.g., the above disclosed method reference FIG. 4A to FIG. 4D Compared to Figure 1A and 1B A typical defect diagram caused by poor substrate wetting under the prior art method is shown, and those skilled in the art will easily appreciate that the defects caused by applying one or more of the various embodiments disclosed herein are significantly reduced. Figure 1A and 1B Each of the defect maps of the substrate in the two examples is obtained by using the same defect level (eg, same sensitivity) as Figure 5 The resulting defect map is taken by the same or similar type of metrology tool.

[0039] Fig. 6A An exemplary embodiment of environmental control of a substrate in a vacuum / atmosphere conversion module is shown. Figure 4D , Fig. 6AAn additional exemplary method 600 of includes operation 601, wherein the substrate is transferred to an inbound vacuum / atmosphere conversion module. The substrate is then transferred to a pretreatment chamber in operation 603. In various embodiments, the pretreatment chamber may include H2 plasma treatment under vacuum as described above. In various embodiments, the vacuum level of the H2 plasma treatment in the pretreatment chamber may be from about 0.1 torr to about 5 torr. A certain temperature range may be applied, and it may be, for example, about 30°C to about 400°C to enhance the formation of free radicals accompanying the plasma, thereby increasing the pretreatment efficiency of the substrate. In various examples, the treatment time in the pretreatment chamber may be, for example, about 30 seconds to about 600 seconds. However, these vacuum levels, temperatures, and times are provided only as examples, and for a particular process, one or more of the vacuum levels, temperatures, and times may vary significantly.

[0040] After the stay in the pre-processing chamber at operation 603, the substrate is transferred to an outbound vacuum / atmosphere conversion module at operation 605. The substrate is kept in the outbound vacuum / atmosphere conversion module for a period of time to convert from the vacuum condition of the pre-processing chamber to near atmospheric pressure.

[0041] At least a portion of the humidification step in operation 455 occurs in the outbound vacuum / atmosphere conversion module. For example, in certain exemplary embodiments, water (H2O) vapor is supplied to the outbound vacuum / atmosphere conversion module to increase H2O vapor adsorption on the substrate surface. In various embodiments, the humidification step may be performed by hydroxyl (OH) - ) layer further promotes the adsorption. As known to those skilled in the art, hydroxide is a minor component of water and is a diatomic anion comprising oxygen and hydrogen atoms (coupled in a covalent bond). Hydroxide molecules generally carry a negative charge.

[0042] Continuing with this specific exemplary embodiment, the partial pressure of H2O is greater than zero but less than water-vapor equilibrium. The pressure within the outbound vacuum / atmosphere conversion module is in the range of, for example, 1 Torr to 20 Torr at a temperature of about 20°C, but other pressures and temperatures are suitable. The temperature of the H2O vapor can be in the range of about 10°C to about 90°C. Depending on other factors discussed herein, the substrate can have a residence time in the H2O vapor of about 10 seconds to about 1200 seconds.

[0043] After the residence time in the outbound vacuum / atmosphere transition module in operation 605, the substrate is transferred back to the plating tank in operation 457. Upon reading and understanding the disclosed subject matter, one skilled in the art will appreciate that the inbound and outbound vacuum / atmosphere transition modules can be the same module that increases or decreases the vacuum and correspondingly decreases or increases the atmospheric pressure depending on whether the substrate is moving into or out of the pre-processing chamber.

[0044] Figure 6B An exemplary embodiment of environmental control for substrates in a stop station module is shown. Figure 4D , Figure 6B An additional exemplary method 610 of the present invention includes an operation 611, wherein the substrate is transferred to an inbound vacuum / atmosphere conversion module. The substrate is then transferred to a pre-treatment chamber at operation 613. In various embodiments, as described above, the pre-treatment chamber may include a H2 plasma treatment under vacuum as described above. For example, various operating parameters may be the same as those described above with reference to Fig. 6A Similar or identical to what is being discussed.

[0045] After staying in the pre-processing chamber in operation 613, the substrate is transferred to the outbound vacuum / atmosphere conversion module in operation 615. The substrate is kept in the outbound vacuum / atmosphere conversion module for a period of time to convert from the vacuum condition of the pre-processing chamber to near atmospheric pressure. After a short stay in the outbound vacuum / atmosphere conversion module, the substrate is transferred to the stop station in operation 617.

[0046] At least a portion of the humidification step in operation 455 occurs in a dwell station. For example, in certain exemplary embodiments, a humidified N2 environment is supplied to the substrate to increase H2O vapor adsorption on the substrate surface. Fig. 6A As disclosed, H2O adsorption can be promoted by a hydroxide layer, wherein the H2O partial pressure is similar to that of the above reference Fig. 6A In this embodiment, the relative humidity can be in the range of, for example, about 20% to about 99%. The N2 flow rate is in the range of, for example, about 1 standard cubic meter per hour (SCMH) to about 200 SCMH, but other flow rates may also be suitable. In various embodiments, the substrate can be rotated at a speed of, for example, about 0 revolutions per minute (RPM) to about 1300 RPM to allow the H2O vapor to be more uniformly adsorbed on the substrate surface. Subsequently, the substrate can be held in the stop station for about 1 second to about 1200 seconds.

[0047] After the dwell time in the stop station at operation 617, the substrate is moved back to the plating tank at operation 457. Upon reading and understanding the disclosed subject matter, one skilled in the art will appreciate that the inbound and outbound vacuum / atmosphere conversion modules can be the same module that increases or decreases the vacuum and correspondingly decreases or increases the atmospheric pressure depending on whether the substrate is moving into a pre-processing chamber or out of a stop station, respectively.

[0048] Although Fig. 6A and 6B Additional processes have been referenced Figure 4D However, those skilled in the art will appreciate that these techniques can also be applied to Figure 4C In addition, Fig. 6A and 6B The additional processing may include separate independent procedures.

[0049] Reference Fig. 7A, which is an illustration of a prior art process 700, wherein H2O molecules previously adsorbed on the substrate surface are stripped or substantially stripped from a metal layer 703 (e.g., Co, Cu, W, or other metals known in the art). For example, if the metal seed film layer 707 is not fully reduced, the metal seed film layer 707 may have a metal oxide (M x O y ) layer 705. The stripped or substantially stripped H2O molecules lead to poor wetting performance in the subsequent plating process as described above, thereby causing fatal defects on the substrate surface (see, for example, Figure 1A and 1B defect diagram).

[0050] Compared to Fig. 7A , Figure 7B It shows that if the metal seed film layer 715 is not completely reduced, the H2O molecules in the presence of the metal seed film layer 715 and possible metal oxides (M x O y ) layer 713 on the surface 710 of the substrate. However, possible metal oxide (M x O y ) layer 713 now has a possible metal oxide (M x O y ) The metal hydroxide M on the layer 713 x (OH) y Layer 711. Thus, as disclosed in the various embodiments above, the surface of the substrate is now humidified again by the adsorption of gaseous H2O molecules (as disclosed in the exemplary embodiments above with respect to humidity, temperature, air flow, time, etc.). In certain embodiments, the surface of the substrate may also be humidified by forming a metal hydroxide M on the surface of the substrate. x (OH) y layer 711, thereby promoting the adsorption of H2O molecules. As described above, the adsorption of H2O molecules significantly improves the wettability of the substrate, thereby resulting in excellent defect performance (for example, see Figure 5 defect diagram).

[0051] Therefore, based on the disclosed subject matter in the various embodiments shown and described herein, it has been found that the wettability of the substrate is related to the oxide (e.g., metal oxide) on the substrate surface during the electrochemical plating process. Therefore, it is generally expected that the seed substrate with the least surface oxide will present good wettability than the seed substrate with one or more surface oxide layers. Therefore, it is expected that the N2 environment FOUP and / or the pre-annealing process and / or the plating process are exposed to H2 plasma and / or the wetting step before the immersion process will improve the wettability of the substrate. The disclosed subject matter presents the importance of surface moisture to the wetting process. On the contrary, it is observed that any process that removes surface moisture from the substrate before plating will produce wettability problems in subsequent plating processes. Therefore, wetting the substrate surface before plating can help to realize these processes with the benefits of these processes as a starting point (e.g., reducing or removing surface oxide).

[0052] Again, those skilled in the art, upon reading and understanding the disclosure provided herein, will appreciate that the wetting treatment steps disclosed herein are significantly different from the operations of the pre-wetting treatment steps discussed elsewhere in the prior art or the operations of condensing the evaporated liquid onto the substrate. As described herein, the pre-wetting treatment or excess water from the condensation will affect the subsequent plating performance within the feature. Therefore, these operations of the prior art will not operate effectively in the applications discussed in the present disclosure. Therefore, the disclosed subject matter is to wet the substrate using water vapor adsorption (in the gas phase), which can be promoted by, for example, a metal hydroxide monolayer or multilayer to achieve an improvement in wettability while avoiding condensation of potentially corrosive seeds as has been implemented in the prior art. The metal hydroxide monolayer or multilayer can also promote water adsorption on the surface of the metal film.

[0053] In general, much effort has been made in the prior art to improve substrate wettability during the immersion step of electrochemical plating processes, with a focus on (1) optimizing the immersion movement speed and rotation (commonly referred to as the "entry profile"); and (2) reducing the surface tension of the plating solution. While both of these approaches have been found to improve wettability to some extent, these approaches impose limitations on the plating hardware on the plating equipment and reduce the process margin required in a high-volume manufacturing environment.

[0054] Thus, the disclosed subject matter provides substantial improvements to wettability issues that, in some applications, cannot be fully addressed by changing the plating bath properties or by changing the access profile of the substrate.

[0055] With any of the embodiments disclosed herein, those skilled in the art, upon reading and understanding the provided disclosure and embodiments, will recognize that the adsorption of gas phase water vapor on the substrate surface is governed by controlling thermodynamic equations by taking into account, for example, relative humidity, partial pressure, temperature, etc. One or more parameters may be modified to control, for example, the overall defect performance parameters of a given device type to increase yield and device performance (see, for example, Figure 5 defect map and related to the prior art method Figure 1A and 1B defect diagram comparison).

[0056] The above description includes illustrative examples, devices, systems and methods that specifically describe the disclosed subject matter. In the specification, for the purpose of explanation, many specific details are set forth to help understand the various embodiments of the disclosed subject matter. However, it will be apparent to those skilled in the art that the various embodiments of the disclosed subject matter can be implemented without these specific details. In addition, well-known structures, materials and technologies are no longer shown in detail to avoid making the multiple illustrated embodiments difficult to understand.

[0057] As used herein, the term "or" may be understood to mean inclusive or exclusive. In addition, those skilled in the art will be able to understand other embodiments after reading and understanding the disclosure provided. In addition, upon reading and understanding the disclosure provided herein, those skilled in the art will readily understand that the various combinations of the techniques and examples provided herein may all be applied in a variety of combinations.

[0058] Although the various embodiments are discussed separately, the individual embodiments are not intended to be considered independent techniques or designs. As described above, each of the various parts can be interrelated, and each can be used alone or in combination with other particulate matter sensor calibration system embodiments discussed herein. For example, although various embodiments of methods, operations, and processes have been described, these methods, operations, and processes can be used alone or in various combinations. Therefore, more than one type of wetting operation can be performed through multiple repeated plating processes or at different stages of the plating operation. When a person skilled in the art reads and understands the disclosure provided herein, it will be further known that the various metal seed films discussed herein may include, but are not limited to, for example, cobalt (Co), copper (Cu), and tungsten (W).

[0059] Therefore, it will be easy for those skilled in the art to make many modifications and changes when reading and understanding the disclosure provided herein. In addition to those listed herein, functionally equivalent methods and devices within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Portions and features of some embodiments may be included in other embodiments, or replace portions and features of other embodiments. These modifications and changes are intended to fall within the scope of the appended claims. Therefore, the present invention shall be limited only by the terms of the appended claims and the full scope of equivalents granted by these claims. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and are not intended to be limiting.

[0060] The abstract of the present invention is provided to enable the reader to quickly determine the nature of the technical disclosure. The abstract is submitted with the understanding that it is not used to interpret or limit the claims. In addition, in the aforementioned embodiments, it can be seen that various features can be combined together in a single embodiment for the purpose of simplifying the present invention. The method of the present invention should not be interpreted as limiting the claims. Therefore, the following claims are hereby incorporated into the detailed description, and each claim is each as a separate embodiment.

Claims

1. A method for reducing oxidation and increasing substrate wettability, the method comprising: placing the substrate in an oxygen-free and deionized humidified substrate environment for a predetermined amount of time, the substrate environment comprising nitrogen; Performing a wetting operation on the substrate, the wetting operation comprising: placing the substrate in a pre-processing chamber, which includes subjecting the substrate to a hydrogen plasma-based process under vacuum; After the hydrogen plasma based process, placing the substrate in a vacuum to atmosphere conversion module; and supplying water vapor to the vacuum-to-atmosphere conversion module to increase water vapor adsorption on the surface of the substrate; performing a plating operation on the substrate; and After the plating operation is performed on the substrate, the substrate is post-annealed in an annealing chamber.

2. The method according to claim 1, wherein: The substrate includes a metal seed layer formed thereon.

3. The method according to claim 1, wherein: The substrate environment is a front-opening wafer transport box.

4. The method of claim 1, further comprising controlling a relative humidity range within the substrate environment to be within a range between 20% and 100%.

5. The method according to claim 1, wherein: The plating operation includes electrochemical deposition.

6. The method of claim 1, further comprising cleaning and drying the substrate in a post-plating chamber.

7. The method according to claim 1, wherein: The post annealing process comprises: annealing the substrate at a temperature range between 30° C. and 400° C. for between 30 seconds and 600 seconds; and Cooling the substrate lasts between 30 and 600 seconds.

8. A method of reducing oxidation and increasing substrate wettability, the method comprising: placing the substrate in a nitrogen-based substrate environment for a predetermined amount of time; Performing a wetting operation on the substrate, the wetting operation comprising: placing the substrate in a pre-processing chamber, which includes subjecting the substrate to a hydrogen plasma-based process under vacuum; After the hydrogen plasma-based process, placing the substrate in a vacuum-to-atmosphere conversion module for a predetermined amount of time to convert from the vacuum conditions of the pre-processing chamber to near atmospheric pressure; placing the substrate in a parking station; and supplying water vapor to the stop station to increase water vapor adsorption on the surface of the substrate; performing a plating operation on the substrate; and After the plating operation is performed on the substrate, the substrate is post-annealed in an annealing chamber.

9. The method according to claim 8, wherein: The humidification operation also includes: After the substrate is placed in the stop station, the substrate is rotated.

10. The method according to claim 9, further comprising: The water vapor adsorption is promoted by forming a hydroxide layer on the surface of the substrate.

11. The method according to claim 9, wherein: The rotation speed of the substrate is between 0 rpm and 1300 rpm.

12. The method according to claim 8, wherein: The substrate includes a metal seed layer formed thereon.

13. The method according to claim 8, wherein: The plating operation includes electrochemical deposition.

14. A method of reducing oxidation and increasing substrate wettability, the method comprising: placing the substrate in a substrate environment for a predetermined amount of time; Performing a pre-annealing process on the substrate using a mixed gas containing hydrogen; After the pre-annealing process, a wetting operation is performed on the substrate, and the wetting operation includes: placing the substrate in a pre-processing chamber, which includes subjecting the substrate to a hydrogen plasma-based process under vacuum; After the hydrogen plasma based process, placing the substrate in a vacuum to atmosphere conversion module; and supplying water vapor to the vacuum-to-atmosphere conversion module to increase water vapor adsorption on the surface of the substrate; performing a plating operation on the substrate; and After the plating operation is performed on the substrate, the substrate is post-annealed in an annealing chamber.

15. The method according to claim 14, wherein: The humidification operation also includes: The substrate is placed in a parking station, which includes spinning the substrate.

16. The method according to claim 15, further comprising: The water vapor adsorption is promoted by forming a hydroxide layer on the surface of the substrate.

17. The method according to claim 15, wherein: The rotation speed of the substrate is between 0 rpm and 1300 rpm.

18. The method according to claim 14, wherein: The substrate includes a metal seed layer formed thereon.

19. The method according to claim 14, wherein: The pre-annealing process and the post-annealing process each include: annealing the substrate at a temperature range between 30° C. and 400° C. for between 30 seconds and 600 seconds; and Cooling the substrate is maintained for between 30 and 600 seconds.

20. A method of reducing oxidation and increasing substrate wettability, the method comprising: placing the substrate in a substrate environment for a predetermined amount of time, the substrate environment comprising at least one of nitrogen and hydrogen; subjecting the substrate to a pretreatment process comprising a hydrogen plasma under vacuum at an elevated temperature; After the substrate is subjected to the hydrogen plasma process, a wetting operation is performed on the substrate, wherein the wetting operation includes: placing the substrate in a pre-processing chamber, which includes subjecting the substrate to a hydrogen plasma-based process under vacuum; After the hydrogen plasma based process, placing the substrate in a vacuum to atmosphere conversion module; and supplying water vapor to the vacuum-to-atmosphere conversion module to increase water vapor adsorption on the surface of the substrate; performing a plating operation on the substrate; and After the plating operation is performed on the substrate, the substrate is post-annealed in an annealing chamber.

21. The method according to claim 20, wherein: The humidification operation also includes: The substrate is placed in a parking station, which includes spinning the substrate.

22. The method according to claim 21, further comprising: The water vapor adsorption is promoted by forming a hydroxide layer on the substrate.

23. The method according to claim 21, wherein: The rotation speed of the substrate is between 0 rpm and 1300 rpm.

24. The method according to claim 20, wherein: The substrate includes a metal seed layer formed thereon.

25. The method according to claim 20, wherein: The post-annealing processes each include: annealing the substrate at a temperature range between 30° C. and 400° C. for between 30 seconds and 600 seconds; and Cooling the substrate is maintained for between 30 and 600 seconds.

26. A system for reducing oxidation and increasing substrate wettability, the system comprising: a substrate environment configured to maintain the substrate having the metal seed layer for a predetermined period of time; a plasma-based chamber configured for performing a hydrogen-based process on the substrate; a pre-treatment chamber configured to subject the substrate to a hydrogen plasma-based process under vacuum; a vacuum-to-atmosphere conversion module configured to supply water to a substrate contained therein to increase water vapor adsorption on a surface of the substrate; as well as The humidification chamber is used to perform a humidification operation on the substrate, and the humidification chamber is configured to supply water vapor to the substrate to increase the water vapor adsorption on the surface of the substrate.

27. The system of claim 26, wherein: The system is also configured to form a hydroxide layer on the surface of the substrate.

28. The system of claim 26, further comprising a plating tank to perform electrochemical deposition on the substrate.

29. A method for controlling wettability of a substrate, the method comprising: placing the substrate in a pretreatment chamber, the pretreatment chamber comprising at least one gas selected from nitrogen and hydrogen; as well as subjecting the substrate to a hydrogen plasma based process under vacuum; After the hydrogen plasma based process, placing the substrate in a vacuum to atmosphere conversion module; supplying water vapor to the vacuum-to-atmosphere conversion module to increase water vapor adsorption on the surface of the substrate; as well as The environment of the pre-processing chamber is controlled to wet the surface of the substrate without increasing an oxide layer on the surface of the substrate.

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