WO2025226409A1

WO2025226409A1 - Electrolytic capacitor and method for forming the same

Info

Publication number: WO2025226409A1
Application number: PCT/US2025/022502
Authority: WO
Inventors: Jason R. HEMPHILL; Justin King; David Bowen; Amanda GILLILAND
Original assignee: Pacesetter Inc
Current assignee: Pacesetter Inc
Priority date: 2024-04-25
Filing date: 2025-04-01
Publication date: 2025-10-30
Anticipated expiration: 2026-10-25

Abstract

A method for manufacturing an electrolytic capacitor for an implantable medical device is provided. The method can include placing a metal foil within an etch solution and etching tunnels in the metal foil during an electrochemical reaction. In addition, the method may include vibrating the metal foil while the metal foil is within the etch solution.

Description

ELECTROLYTIC CAPACITOR AND METHOD FOR FORMING THE SAME CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority to U.S. Provisional Patent Application No.63/638,699, filed Apr.25, 2024, entitled “ELECTROLYTIC CAPACITOR AND METHOD FOR FORMING THE SAME”, the subject matter of which is incorporated herein by reference in its entirety. BACKGROUND [0002] Embodiments herein generally relate to electrolytic capacitors utilized for implanted medical devices (IMDs). [0003] High voltage capacitors are utilized as energy storage reservoirs in many applications, including IMDs. These capacitors are required to have a high energy density, to minimize the overall size of the implanted device. Further, for IMD applications, because the IMD is subcutaneous, or under the skin of the patient, the size of the IMD must remain minimal. Meanwhile, the capacitor can represent the largest electrical component within the IMD. In one example the IMD can be an implantable cardioverter defibrillator (ICD), or more specifically a subcutaneous implantable cardioverter defibrillator (SICD), [0004] High voltage ventricular-tachy therapies are delivered by subcutaneous implantable cardioverter defibrillator (SICD) devices after the tachycardia episode is detected and classified. Several SICD devices use a conventional bi-phasic capacitive discharge waveform that is delivered from a bank of multiple capacitors that are connected in series. Conventional SICD devices deliver about 80J of energy in a single bi-phasic shock. In order to generate a high energy shock of 80J, the SICD devices require a bank of large high voltage capacitors connected in series and typically charged to 800V-900V. 15662WOO1 (013-0610PCT1) 1 PATENT The capacitor bank and battery are two of the larger components in SICD devices and thus the overall size of the device is largely dependent on the space needed to house the capacitor bank and battery. For example, the space requirements of the capacitor bank and battery cause the SICD devices to be 60cc, 70cc or larger. [0005] One type of high voltage capacitor is an aluminum electrolytic capacitor. Aluminum electrolytic capacitors energy density is directly related to the surface area of the anodes generated in the electrochemical etching processes. Typical surface area increases are 40 to 1 and represent 30 to 40 million tunnels/cm2. An electrochemical widening step is used to increase the tunnel diameter after etching to ensure the formation oxide does not close off the tunnels. Closing off the tunnels during formation reduces capacitance and electrical porosity. [0006] During the preparation of the raw metal foil, it is important that proper thermal oxide is grown on the surface of the metal foil during a final anneal treatment and the specific chemical components, such as Cu, Si, and Fe, are within the first 5 to 10 microns of the surface. Without proper preparation of the oxide and impurities, the raw metal foil will not etch efficiently to give the highest metal foil capacitance. [0007] US Patent 11,476,057 describes using molybdenum as a galvanic difference compared to the aluminum foil and allows for aluminum dissociation in a low pH etch solution before the electrochemical process is run. Additionally, having a galvanic difference during the etching process increases the aluminum foil capacitance after a presoak. [0008] US Patent 6,858,126 meanwhile describes using titanium as a catalysis in a low pH etch solution to increase metal foil capacitance, as well. But the use of the titanium in a low pH etch solution treatment before the electrochemical process is not detailed. 15662WOO1 (013-0610PCT1) 2 PATENT [0009] With or without a galvanic material in the presoak and etching process, hydrogen evolvement during the chemical or electrochemical dissolution of the aluminum can cause tunnels to stop “growing” into the thickness due to diffusion slowing and causing final passivation of the end of the tunnel. Therefore, as diffusion becomes slower due to tunnel length of aluminum and hydrogen out and chloride in, the passivation of the tunnel to stop growing occurs. This can limit metal foil capacitance from the surface area fully developing due to hindrance of diffusion and tunnel growth. Thus, a need exists for an improved method for forming an electrolytic capacitor. SUMMARY [0010] In accordance with embodiments herein, a method for manufacturing an electrolytic capacitor for an implantable medical device is provided. The method can include placing a metal foil within an etch solution and etching tunnels in the metal foil during an electrochemical reaction. In addition, the method may include vibrating the metal foil while the metal foil is within the etch solution. [0011] Optionally, the method can also include presoaking the metal foil in the etch solution for a determined period of time before etching the tunnels in the metal foil, and the vibrating of the metal foil may occur either during the presoaking or during the etching. In one aspect, the determined period of time can be between 5 and 20 seconds. In another aspect, the method can also include widening the tunnels in the metal foil after etching the tunnels in the metal foil, and the vibrating of the metal foil can occur during at least one of the presoaking, the etching, or the widening. In one example vibrating the metal foil can include providing a linear displacement of the metal foil or a non-linear displacement of the metal foil. [0012] Optionally, vibrating the metal foil can include at least one of vibrating the metal foil directly or vibrating the metal foil indirectly. In one aspect 15662WOO1 (013-0610PCT1) 3 PATENT vibrating the metal foil directly can include engaging the metal foil with a probe and providing vibrational energy. In another aspect vibrating the metal foil indirectly may include vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil. In one example, the metal foil can be an aluminum foil and the etch solution is a chloride solution with an oxidizer that is at least 5% by weight of the chloride solution. In another example, the etch solution may also include 10 to 4000 ppm molybdic acid. [0013] In accordance with embodiments herein, a method for manufacturing an electrolytic capacitor for an implantable medical device is provided that can include presoaking an aluminum foil in an etch solution that includes molybdenum for a determined period of time and etching the aluminum foil within the etch solution to form tunnels within the aluminum foil. The method can also include widening the tunnels of the aluminum foil, and the vibrational energy can be applied to the aluminum foil during at least one of the presoaking, etching or widening. [0014] Optionally, vibrating the aluminum foil can include at least one of vibrating the aluminum foil directly or vibrating the metal foil indirectly. In one aspect vibrating the aluminum foil directly can include engaging the metal foil with a probe and providing vibrational energy at a linear displacement or a non-linear displacement. In another aspect, vibrating the aluminum foil indirectly can include vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil. [0015] In accordance with embodiments herein, a method for manufacturing an electrolytic capacitor for an implantable medical device is provided that can include presoaking an aluminum foil in an etch solution that includes molybdenum for a determined period of time and applying a determined current density to the etch solution to etch to form tunnels within the aluminum foil. The method can also include widening the tunnels of the aluminum foil to form an 15662WOO1 (013-0610PCT1) 4 PATENT electrolytic material and applying vibrational energy to the aluminum foil during each of the presoaking, applying, and widening. [0016] Optionally, the determined period of time can be between 5 and 20 seconds and the determined current density is between 0.25 to 0.3 amps/cm². In one aspect the method can also include forming an electrolytic capacitor having an anode formed from the electrolytic material. In another aspect, vibrating the aluminum foil can comprise at least one of vibrating the aluminum foil directly or vibrating the metal foil indirectly. In one example, applying vibrational energy can include providing either linear displacement on the aluminum foil or non-linear displacement on the aluminum foil. In another example, vibrating the aluminum foil indirectly can include vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil. DESCRIPTION OF THE DRAWINGS [0017] Figure 1 illustrates a block flow diagram of a process of forming an electrolytic material in accordance with embodiments herein. [0018] Figure 2A illustrates an electrochemical etch system for forming an electrolytic capacitor in accordance with embodiments herein. [0019] Figure 2B illustrates an electrochemical etch system for forming an electrolytic capacitor in accordance with embodiments herein. [0020] Figure 2C illustrates an electrochemical etch system for forming an electrolytic capacitor in accordance with embodiments herein. [0021] Figure 2D illustrates an electrochemical etch system for forming an electrolytic capacitor in accordance with embodiments herein. [0022] Figure 3 illustrates a schematic diagram of an IMD in accordance with embodiments herein. 15662WOO1 (013-0610PCT1) 5 PATENT [0023] Figure 4 illustrates a schematic block diagram of an IMD in accordance with embodiments herein. [0024] Figure 5 illustrates a metal foil that is formed without using vibrational energy as disclosed in the process described in relation to Figure 1. [0025] Figure 6 illustrates a metal foil that is formed using the disclosed process as described in relation to Figure 1. DETAILED DESCRIPTION [0026] It will be readily understood that the components of the embodiments as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations in addition to the described example embodiments. Thus, the following more detailed description of the example embodiments, as represented in the figures, is not intended to limit the scope of the embodiments, as claimed, but is merely representative of example embodiments. [0027] Reference throughout this specification to “one embodiment” or “an embodiment” (or the like) means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” or the like in various places throughout this specification are not necessarily all referring to the same embodiment. [0028] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the various embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other 15662WOO1 (013-0610PCT1) 6 PATENT instances, well-known structures, materials, or operations are not shown or described in detail to avoid obfuscation. The following description is intended only by way of example, and simply illustrates certain example embodiments. [0029] The methods described herein may employ structures or aspects of various embodiments (e.g., systems and/or methods) discussed herein. In various embodiments, certain operations may be omitted or added, certain operations may be combined, certain operations may be performed simultaneously, certain operations may be performed concurrently, certain operations may be split into multiple operations, certain operations may be performed in a different order, or certain operations or series of operations may be re-performed in an iterative fashion. It should be noted that, other methods may be used, in accordance with an embodiment herein. Further, wherein indicated, the methods may be fully or partially implemented by one or more processors of one or more devices or systems. While the operations of some methods may be described as performed by the processor(s) of one device, additionally, some or all of such operations may be performed by the processor(s) of another device described herein. [0030] It should be clearly understood that the various arrangements and processes broadly described and illustrated with respect to the Figures, and/or one or more individual components or elements of such arrangements and/or one or more process operations associated of such processes, can be employed independently from or together with one or more other components, elements and/or process operations described and illustrated herein. Accordingly, while various arrangements and processes are broadly contemplated, described and illustrated herein, it should be understood that they are provided merely in illustrative and non-restrictive fashion, and furthermore can be regarded as but mere examples of possible working environments in which one or more arrangements or processes may function or operate. 15662WOO1 (013-0610PCT1) 7 PATENT [0031] All references, including publications, patent applications and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. Terms [0032] The term “electrolytic material” when used herein includes any and all material utilized in making the electrically active part(s) or component(s) of an electrolytic capacitor. [0033] The term “electrolytic capacitor” when used herein refers to any capacitor that is polarized and includes an anode or positive component, plate, layer etc. made from a metal to provide an insulating oxide layer through anodization that functions as a dielectric. An electrolyte covers, engages, interacts with the oxide layer to provide a negative component, plate, layer, etc. and functions as a cathode. In one example, the electrolytic capacitor is an aluminum electrolytic capacitor that utilizes aluminum as the metal of the anode. [0034] The term “metal foil” when used herein refers to any metallic material that may be made into an electrolytic material. In one example, the metal foil can be an aluminum metal foil. [0035] The term “etching” as used herein refers to a process by which a metal foil is altered by placing the metal foil in an etching solution and connecting to a positive pole of a source of direct electric current to the metal foil. In one example the metal foil can be an aluminum foil and the etching solution can be a molybdenum containing compound that is mixed with a chloride solution that contains an oxidizer. In one example etching results in the formation of tunnels in the metal foil. 15662WOO1 (013-0610PCT1) 8 PATENT [0036] The term “vibrations” as each used herein refer to any and all oscillations of a material such as a metal foil. The act or action that causes the vibrations is referred to as “vibrating.” The energy that is applied that causes the vibrating, or vibrations is referred to as “vibrational energy.” In example embodiments the vibrational energy can be mechanical excitation, electrical excitation, or the like. The oscillation itself in example embodiments may be sinusoidal, repetitive, non-repetitive, random, etc. The oscillation can be a linear displacement, a non-linear displacement, be a formed using a sinusoidal wave, square wave, sawtooth wave, patterned wave, non-patterned wave, or the like. In one example the linear displacement or non-linear displacement result in displacements during tunnel formation. To cause the vibrations in example embodiments the frequency applied can be between 10Hz and 300Hz. In other example embodiments, the vibration may include vibration characteristics based on vibrational energy applied. The vibration characteristics can include amplitude, frequency, waveform, wavelength, or the like. The vibration characteristics may vary depending on the application. [0037] The term “foil holder” when used herein refers to any device or implement that provides forces to hold or engage the metal foil while the metal foil is within an etch solution. In example embodiments the foil holder may be or include a compression member, clamp, clip, or the like. In one example a foil holder can include a clip that is within the foil holder that frictionally engages or holds a metal foil in place. In another example the foil holder can include a pair of handles, a pivot point, and a clip such that compressing the handle results in the clip opening, or releasing the metal foil, and releasing the handle causes the jaws of a clip to compress the metal foil between the clip. A foil holder can be any device or implement where vibrational energy applied to the foil holder results in vibration of the metal foil. 15662WOO1 (013-0610PCT1) 9 PATENT [0038] The term “clip” when used herein refers to a portion or part of a foil holder that contacts the metal foil. The clip can provide compression forces, friction forces, form fitting, engagement forces, or the like to engage and hold the metal foil. [0039] Embodiments may be implemented in connection with one or more implantable medical devices (IMDs). Non-limiting examples of IMDs include one or more of neurostimulator devices, implantable cardiac monitoring and/or therapy devices. For example, the IMD may represent a cardiac monitoring device, pacemaker, cardioverter, cardiac rhythm management device, implantable cardioverter defibrillator (ICD), neurostimulator, leadless monitoring device, leadless pacemaker, an external shocking device (e.g., an external wearable defibrillator), and the like. For example, the IMD may be a subcutaneous IMD that includes one or more structural and/or functional aspects of the device(s) described in U.S. Patent 10,765,860, titled “Subcutaneous Implantation Medical Device With Multiple Parasternal-Anterior Electrodes” and filed May 7, 2018; U.S. Patent 10,722,704 titled “Implantable Medical Systems And Methods Including Pulse Generators And Leads” filed May 7, 2018; US Patent 11,045,643, titled “Single Site Implantation Methods For Medical Devices Having Multiple Leads”, filed May 7, 2018, which are hereby incorporated by reference in their entireties. Additionally or alternatively, the IMD may include one or more structural and/or functional aspects of the device(s) described in U.S. Patent 9,333,351 “Neurostimulation Method and System to Treat Apnea” and U.S. Patent 9,044,710 “System and Methods for Providing A Distributed Virtual Stimulation Cathode for Use with an Implantable Neurostimulation System”, which are hereby incorporated by reference. Further, one or more combinations of IMDs may be utilized from the above incorporated patents and applications in accordance with embodiments herein. 15662WOO1 (013-0610PCT1) 10 PATENT [0040] Additionally or alternatively, the IMD may include one or more structural and/or functional aspects of the device(s) described in U.S. Patent 9,216,285 “Leadless Implantable Medical Device Having Removable and Fixed Components” and U.S. Patent 8,831,747 “Leadless Neurostimulation Device and Method Including the Same”, which are hereby incorporated by reference. Additionally or alternatively, the IMD may include one or more structural and/or functional aspects of the device(s) described in U.S. Patent 8,391,980 “Method and System for Identifying a Potential Lead Failure in an Implantable Medical Device”, U.S. Patent 9,232,485 “System and Method for Selectively Communicating with an Implantable Medical Device”, EP Application No.0070404 “Defibrillator” and, U.S. Patent 5,334,045 “Universal Cable Connector for Temporarily Connecting Implantable Leads and Implantable Medical Devices with a Non-Implantable System Analyzer”, U.S. Patent 10,729,346 titled "Method And System For Second Pass Confirmation Of Detected Cardiac Arrhythmic Patterns"; U.S. Patent Application 15/973,351, Titled "Method And System To Detect R- Waves In Cardiac Arrhythmic Patterns”; U.S. Patent 10,874,322, titled "Method And System To Detect Post Ventricular Contractions In Cardiac Arrhythmic Patterns"; and U.S. Patent 10,777,880, titled "Method And System To Detect Noise In Cardiac Arrhythmic Patterns” which are hereby incorporated by reference. [0041] Additionally or alternatively, the IMD may be a leadless cardiac monitor (ICM) that includes one or more structural and/or functional aspects of the device(s) described in U.S. Patent 9,949,660, filed March 29, 2016, entitled, "Method and System to Discriminate Rhythm Patterns in Cardiac Activity"; U.S. Patent 10,729,346, titled “Method And System For Second Pass Confirmation Of Detected Cardiac Arrhythmic Patterns”; U.S. Patent 11,020,036, titled “Method And System To Detect R-Waves In Cardiac Arrhythmic Patterns”; U.S. Patent 10,874,322, titled “Method And System To Detect Post Ventricular Contractions In Cardiac Arrhythmic Patterns”; and U.S. Patent 10,777,880, titled "Method And 15662WOO1 (013-0610PCT1) 11 PATENT System To Detect Noise In Cardiac Arrhythmic Patterns", which are expressly incorporated herein by reference. [0042] Provided is an electrolytic capacitor that is manufactured using a molybdenum containing compound that is mixed with a low pH chloride solution that contains a strong oxidizer in the 10 to 100 ppm concentration range. In one example the low pH etch solution concentrations are 60 to 80 ppm molybdic acid with 0.62 wt.% hydrochloric acid, 0.92 wt.% sulfuric acid, 3.5 wt.% sodium perchlorate, and 60 ppm nonafluorobutanesulfonic acid (FBSA) or salts thereof (KFBS). The aluminum foil is placed in the etch tank with the low pH etch solution with molybdic acid for 5 to 20 seconds and then, the electrochemical process is started at 0.25 to 0.3 amps/cm² current density. Vibrational energy as a result of physical excitation is applied to the aluminum foil during both the presoak and the electrochemical etch. In addition, this physical excitation can also be applied during the widening process. [0043] The method of utilizing the physical excitation during the manufacturing steps has shown to increase the metal foil capacitance as much as 6% compared to only using the moly acid process in US Patent 11,476,057. Therefore, the use of the method can increase the energy density of the capacitor by up to 6%, or lower etching coulombs could be applied to maintain the same metal foil capacitance to produce stronger metal foil (higher yield – and thus provide manufacturing cost savings). With the use of the moly acid process with vibrational (energy) excitation applied to the metal foil in the various steps of etch and widening, a 13% to 15% increase in metal foil capacitance has been observed compared to using the US Patent 11,476,057 process that does not include physical excitation. [0044] In one example, a metal foil can be placed in a 400-ppm molybdic acid with 0.62 wt.% hydrochloric acid, 0.92 wt.% sulfuric acid, 3.5 wt.% sodium perchlorate, and 60 ppm nonafluorobutanesulfonic acid (FBSA) or salts thereof 15662WOO1 (013-0610PCT1) 12 PATENT (KFBS) etch solution at 80 deg C for 5 to 20 seconds. Next, the metal foil is etched in the same bath electrochemically at 80 deg C for 2 minutes at 0.25 to 0.3 amps/cm². [0045] During the presoaking and electrochemical etching, vibrational energy is applied to the metal foil by several methods. In one example, a probe may contact the metal foil and may be electrodynamically driven to mechanically “poke” the metal foil with either a linear displacement (e.g., periodic waveform) or a non-linear displacement. In example embodiments the linear displacement can include sine waves, square waves, triangular waves, sawtooth waves, or the like). Whereas with non-linear displacement of the metal foil, no discernable pattern is provided. [0046] The vibrational energy may include numerous different vibration characteristics. In example embodiments the vibrational energy can have a frequency of about 30 to 50 Hz, whereas in other examples the range of the frequency can be 10 Hz and 300 Hz. In yet other examples the frequency can be less than 10 Hz or more than 300 Hz. In another example, a metal foil holder of the metal foil in the etch tank can be vibrated utilizing same or similar frequencies and wave patterns. In yet another example, a clip, or other component that holds or engages the metal foil may be vibrated resulting in the vibration being applied to the metal foil via the clip or other component. In one example two or more components (e.g., the metal foil is vibrated while the clip is vibrated, the metal foil is vibrated while the metal foil holder is vibrated, etc.). When two different components are vibrated, such vibrations can occur at the same frequency, different frequencies, using different waveforms, using both linear displacement and non-linear displacement or the like. In addition to differing frequencies and waveforms, other vibration characteristics causing the vibrational energy can be varied including wavelength, amplitude, waveform, wave morphology, or the like. 15662WOO1 (013-0610PCT1) 13 PATENT [0047] The use of the vibrational energy increases the diffusion of the hydrogen bubbles and aluminum out of the tunnels and pits and increases diffusion of chloride into the tunnels. The constant exchange of ions and gas at a high rate keeps the tunnels from passivating. Additionally, due to surface tension, hydrogen can stick to the aluminum surface and block etching. Physical excitation discourages adhesion and physical size of the gas bubbles to allow for continuity of initiated etch tunnel progression as well as promotion of proximal initiation sites, yielding higher tunnel density and growth. The resulting increase in the surface area leads to higher metal foil capacitance. In addition, the metal foil can be widened electrochemically with the same approach of using physical excitation. The metal foil can then be formed. [0048] In an example, the average sheet capacitance of a control without the molybdic acid additive and the 5 to 20 second presoak was 325 microF and the average sheet capacitance using the molybdic acid additive at 400 ppm and a 9 second presoak with physical excitation only during etch and presoak was 373 microF. The increase from 325 microF to 373 micoF represents a 12.8% increase in metal foil capacitance. Capacitors built using the method described herein showed an 11% to 12% increase in delivered energy over the control. The capacitor pairs built with the method described herein allowed for a 40J cap pair at nominal voltage versus 36J and a 44.5J cap pair at safety shock over 40J. This could allow for higher longevity if applied or higher current densities above 6J/cc for future designs. Lastly, the increase in metal foil capacitance allows for more degrees of freedom of design for other ICD device components and still maintain overall dimensions and electrical outputs. When physical excitation was used only at widening, a 1.5% increase in metal foil capacitance was found over not using the vibrational excitation. [0049] Figure 1 illustrates a method 100 for forming an electrolytic capacitor. In one example the systems, assemblies, devices, components, etc. 15662WOO1 (013-0610PCT1) 14 PATENT described herein in Figs.2A-2C are utilized to perform one or more steps of the method 100. [0050] At 102, a metal foil is placed in an etch tank with a low pH etch solution with an acid to presoak the metal foil for a determined period of time at a determined temperature. In one example the metal foil can be an aluminum foil. In another example the acid can be molybdic acid. In yet another example the determined period of time can be between 5 to 20 seconds. In another example the determined temperature is approximately 80 degrees Celsius (C). [0051] A molybdenum containing compound may be mixed with a low pH chloride solution that contains a strong oxidizer in the 10 to 100 ppm concentration range. In one example the low pH etch solution concentrations are 60-80 ppm molybdic acid with .62 wt% hydrochloric acid, .92 wt% sodium perchlorate, and 60 ppm nonafluorobutanesulfonic acid (FBSA) or salts thereof (KFBS). In another example, the metal foil is placed in a 400-ppm molybdic acid with .62 wt% hydrochloric acid, .92 wt.% sulfuric acid, 3.5 wt% sodium perchlorate, and 60 ppm FBSA or KFBS etch solution at approximately 80 degrees C for 5 to 20 seconds. [0052] At 104, during the presoak of the metal foil, vibrational energy is applied to the metal foil. Applying vibrational energy or vibrating the metal foil during the presoak process increases the diffusion of the hydrogen bubbles and aluminum out of the tunnels and pits. In addition, the applied vibration increases the diffusion of chloride into the tunnels. The constant exchange of ions and gas keeps the tunnels from passivating. Additionally, due to surface tension, hydrogen can stick to the aluminum surface and block etching. Physical excitation from the applied vibration discourages adhesion and reduces the physical size of the gas bubbles to allow for continuity of initiated etch tunnel progression as well as promotion of proximal initiation sites, yielding higher tunnel density and growth. The resulting increase in the surface area leads to higher metal foil capacitance. 15662WOO1 (013-0610PCT1) 15 PATENT [0053] In one example, vibrating the metal foil during the presoak a probe (2A) is provided that contacts the metal foil. The probe can be electrodynamically driven to mechanically “poke” the metal foil with a periodic waveform (e.g., sine, square, triangular, sawtooth, or the like). In one example the frequency of the periodic waveform can be between 30Hz and 50Hz. Alternatively, in another embodiment, the metal foil holder that secures the metal foil within a presoak tank is vibrated. As a result, the metal foil itself is similarly vibrated as a result of being held by the metal foil holder (Fig.2B). In yet another example, a clip (Fig.2C) that holds the metal foil can be vibrated. Again, because the clip engages the metal foil, the vibration of the clip results in the vibration of the metal foil. In each instance the vibration provided can be between 30Hz and 50Hz. [0054] At 106, electrochemical etching of the metal foil is initiated while the metal foil continues to be vibrated. Electrochemical etching is a process occurs when a current flows between a metallic conductor (e.g., aluminum foil) that is immersed in an electrolyte (e.g. molybdic acid) resulting in both electrical and chemical reactions. As a result of the electrical and chemical reactions numerous tunnels and/or pits are formed within the metal foil. Each tunnel results in an increase of surface area, which in turn increases potential energy density of the metal foil. Thus, there is a desire to form as many tunnels in the metal foil as possible, and to ensure that such formed tunnels do not close during the manufacturing process. [0055] To provide the electrochemical reaction, a current is applied to the low pH etch solution within the tank with the metal foil still within the tank. In one example the electrochemical process can be started with a .25 to .3 amps/cm^2 current density. [0056] By continuing to vibrate (or apply vibrational energy) to the metal foil during the electrochemical etching process increases the diffusion of chloride into the tunnels. The constant exchange of ions and gas keeps the tunnels and gas 15662WOO1 (013-0610PCT1) 16 PATENT keeps the tunnels from passivating during the electrochemical process, similar to the presoak. Additionally, a reduction of hydrogen sticking to the metal foil surface that blocks etching also occurs as a result of the vibration. Physical excitation from the applied vibration additionally discourages adhesion and reduces the physical size of the gas bubbles to allow for continuity of initiated etch tunnel progression as well as promotion of proximal initiation sites, yielding higher tunnel density and growth. Thus, greater surface area is achieved during the electrochemical etching process as a result of the vibrational energy. [0057] At 108, a widening process of the formed tunnels in the metal foil is undertaken while the vibrational energy continues to be applied to form the anode (e.g. electrolytic material) for an electrolytic capacitor. The widening of the tunnels not only ensures that the tunnels do not close, but also increases the total surface area of the metal foil. Examples of the etching and widening processes (but not the addition of the applied vibrational energy) may be found in U.S. Pat. Nos. 10,872,731, 6,858,126, 6,802,954, and 8,535,507, the disclosures of which are incorporated herein by reference. Etching and widening processes that produce tunnels in a metal foil are not required for using the metal foil as an anode within a capacitor. However, the presence of tunnels or pores in the metal foil drastically increases the surface area of the anode and therefore the capacity and charge density of the capacitor. The etched metal foil may be anodized prior to formation of the oxide layer, for example, by methods described in U.S. Pat. No.7,175,676, the disclosure of which is incorporated herein by reference. [0058] FIG. 2A illustrates an electrochemical etch system 200A that is suitable for performing an electrochemical etch. Such electrochemical etch system is similar to that as described in U.S. Pat. No.11,476,057 that is incorporated by reference in full herein. The electrochemical etch system 200A includes a reservoir or etch tank 202 that holds an etch solution that can serve as the electrochemical etch bath. A cathode 203 can contact the etch bath within the tank 202. Suitable 15662WOO1 (013-0610PCT1) 17 PATENT cathodes 203 can include, but are not limited to, titanium, glassy carbon, and graphite. [0059] As shown by the arrow labeled A in FIG.2A, metal foil 204 is placed in electrical communication with a potential source 206 that is in electrical communication with the cathode 203. For instance, a wire or electrical cable can be clipped to the metal foil 204. Suitable potential sources 206 can include, but are not limited to, DC power sources such as a DC power supply, rectifier power supply, and a battery. The metal foil 204 can be placed fully or partially in the etch solution within the tank 202 as illustrated by the arrow labeled A in FIG.2A. The metal foil is placed in the etch solution within the tank 202 such that at least one face of the metal foil 204 is in direct physical contact with the etch solution within the tank 202. [0060] Electronics 207 can be in electrical communication with the electrochemical etch system 200A to control the operation of the electrochemical etch system 200A. For instance, the electronics 207 can determine when to place the metal foil 204 in the etch solution in the tank and when to begin the electrochemical etch upon expiration of a determined period for presoaking the metal foil 204 in the etch solution. For instance, an operator can place the metal foil 204 in the etch solution and once the metal foil is in the desired location in the etch solution, the user can active a user interface such as pressing a button to indicate to the electronics 207 that the that the metal foil is placed in the etch solution. In response, the electronics can start measuring the time of the chemical etch, including the presoak and etching process. Upon or after the electronics 207 determine that the electrochemical etch presoaking duration has passed, the electronics can start the electrochemical etch by applying to metal foil the electrical potential for the electrochemical etch. [0061] Figures 2B-2D illustrate addition assemblies 200B, 200C, 200D for forming an electrolytic material for an electrolytic capacitor that can accomplish 15662WOO1 (013-0610PCT1) 18 PATENT the method of Figure 1. In one example, at least one of the steps, if not all of the steps of the method of Figure 1 are performed using one or more components of the assemblies 200B-200D of Figures 2B-2D. [0062] Similar to the assembly 200A of Figure 2A, each of the assemblies 200B-200D has an etch tank 202 that is configured to hold the etch solution such as a low pH etch solution with an acid. The etch tank 202 can be a container, vessel, or the like. In one example the acid can be molybdic acid, and the solution can be as described in relation to Figure 1. [0063] Each assembly 200B-200D includes a potential source 206 configured to apply a direct current to the etch solution that results in an electrochemical reaction between a metal foil 204 suspended in the etch solution and the etch solution resulting in tunnel formation in the metal foil. In an example the metal foil can be an aluminum foil. In one example the potential source 206 provides a current having between .25 to .3 amps/cm^2 current density to cause the electrochemical reaction that results in the formation of the tunnels. In all, the potential source 206 is configured such that the etch solution chemically interacts with the metal foil 204 to product chemical reactions resulting in the formation of the tunnels with the metal foil 204. [0064] The etch tank 202 can also include a heating device 208 configured to heat the etch solution. In one example the heating device 208 heats the etch solution between 70 degrees C and 90 degrees C. In one example the heating device 208 heats the etch solution to 80 degrees C. The heating device 208 in example embodiments can be an electric heating device, conductive heating device, or the like. [0065] Each assembly 200B-200D additionally includes multiple examples of foil holders 210A that include a clip 211A, 211B for holding the metal foil 204 within the etch solution of the tank 202. In one example the foil holder 210A 15662WOO1 (013-0610PCT1) 19 PATENT includes a body with a clip 211A that frictionally receives the metal foil holder 210A therein. Alternatively the potential source 206 in this example can be considered a foil holder and can also include handles 212 and a pivot point 213 such that compression of the handles 212 together causes in the jaws of the clip 211B to open based on a force, such as a compression spring force at the pivot point. Such compression spring biases the jaws of the clip 211B together to hold the metal foil 204. When the handles 212 are compressed, the compression force on the handles results in the spring biasing force being overcome, opening the jaws of the clip 211B. In another example a clip can engage the metal foil 204. [0066] Each assembly additionally includes a vibration device 214A, 214B, 214C, 214D that is configured to couple to either the metal foil 204 (Figure 2B), the foil holder 210A (Figure 2C), or the clip 211A (Figure 2D). While in the example Figures multiple vibration devices are illustrated, this is for illustration purposes only, and in other example embodiments only one vibration device is provided to vibrate the metal foil. Each vibration device can vibrate the metal foil 204 either directly via direct contact with the metal foil (Figure 2B) or indirectly via contact with the holder or clip that contact the metal foil. The vibration can be caused indirectly as a result of vibrating a component that ultimately causes vibration of the metal foil 204. In this manner, for each foil holder (206) and 210a a vibration device 214B, 214C, 214D can apply vibrational energy or force to any portion of the metal foil 204, foil holder 210A, or clip (206), 211A, 211B to cause the metal foil 204 to vibrate. In one example the foil holder and vibration device can be the same device. For example, the foil holder can be a device that functions to both hold or secure the metal foil 204 in a determined location while also applying a current, movement, sinusoidal movement, or the like to the metal foil 204 itself. [0067] In one example, the vibrational energy can be applied during a presoaking process when the metal foil 204 is suspended in the etch solution, along with during the etching process when current is applied to the etch solution 15662WOO1 (013-0610PCT1) 20 PATENT to cause the formation of tunnels as a result of the electrochemical reaction of the etch solution with the metal foil. In addition, the vibrational energy can also be applied to the metal foil during a tunnel widening process. [0068] In another example the vibrating is applied to the metal foil 204 by utilizing a vibration device 214B that is a probe that contacts the metal foil 204 as illustrated in Figure 2B. The probe can be configured to provide a periodic waveform with a frequency between 30 Hz and 50 Hz. The periodic waveform can be a sine waveform, square waveform, triangular waveform, sawtooth waveform, or the like. In one example the probe generates the periodic waveform electromechanically by having an actuator that is electrically powered and pokes, or moves, the metal foil at a determined frequency. In one example the frequency can be between 30 Hz and 50 Hz. In another example the frequency can be less than 30 Hz or more than 50 Hz. [0069] In another example the vibrational energy can be applied to the metal foil via the foil holder as illustrated in Figure 2C. In such an example, again the vibration device 214C can be a probe that can attach to the foil holder 210A instead of the metal foil 204 itself. Similarly, in the example of Figure 2D the vibration device 214D can be probe that attaches to a clip 211B of the metal foil 204. While shown as a probe in Figures 2B-2D additional vibration devices can be provided that result in vibration of the metal foil 204 during any of the steps of the etching process. By having the vibrational energy applied to the foil holders (206) 210a or clips 211A, 211B instead of the metal foil itself, more area of the metal foil is exposed to the etching solution resulting in a greater tunnel formation during the etching process. [0070] Figure 3 illustrates a schematic diagram of an implantable medical system 361 that is configured to apply VF therapy in accordance with embodiments herein. Embodiments may be implemented in connection with one or more subcutaneous implantable medical devices (S-IMDs). Non-limiting 15662WOO1 (013-0610PCT1) 21 PATENT examples of S-IMDs include one or more of subcutaneous implantable cardioverter defibrillators (SICD). For example, the S-IMD may include one or more structural and/or functional aspects of the device(s) described in U.S. Patent 10,722,704 titled “IMPLANTABLE MEDICAL SYSTEMS AND METHODS INCLUDING PULSE GENERATORS AND LEADS”, filed May 07, 2018; U.S. Patent 10,765,860 titled “SUBCUTANEOUS IMPLANTATION MEDICAL DEVICE WITH MULTIPLE PARASTERNAL-ANTERIOR ELECTRODES”, filed May 07, 2018; which are hereby incorporated by reference in their entireties. [0071] The system 361 includes a subcutaneous implantable medical device (S-IMD) 363 that is configured to be implanted in a subcutaneous area exterior to the heart. The S-IMD 363 is positioned in a subcutaneous area or region, and more particularly in a mid-axillary position along a portion of the rib cage 375. Optionally, the system 361 may also include a leadless pacemaker 369 implanted within the heart, such as at an apex 371 of the right ventricle. Optionally, the leadless pacemaker 369 may be omitted entirely. The system 361 does not require insertion of a transvenous lead. [0072] The pulse generator 365 may be implanted subcutaneously and at least a portion of the lead 367 may be implanted subcutaneously. In particular embodiments, the S-IMD 363 is an entirely or fully subcutaneous S-IMD. Optionally, the S-IMD 363 may be positioned in a different subcutaneous region. [0073] The S-IMD 363 includes a pulse generator 365 and at least one lead 367 that is operably coupled to the pulse generator 365. The lead 367 includes at least one electrode segment 373 that is used for providing MV shocks for defibrillation. In particular, an electrolytic capacitor manufactured utilizing the process of Figure 1 can be utilized to provide the MV shocks. Optionally, the lead 367 may include one or more sensing electrodes. The pulse generator 365 includes a housing that forms or constitutes an electrode utilized to deliver MV 15662WOO1 (013-0610PCT1) 22 PATENT shocks. The electrode associated with the housing of the pulse generator 365 is referred to as the “CAN” electrode. [0074] In an alternative embodiment, the lead 367 may include one or more electrode segments, in which the electrode segments are spaced apart from one another having an electrical gap therebetween. The lead body may extend between the gap. One electrode segment may be positioned along an anterior of the chest, while another electrode segment may be positioned along a lateral and/or posterior region of the patient. The electrode segments may be portions of the same lead, or the electrode segments may be portions of different leads. The electrode segments may be positioned subcutaneously at a level that aligns with the heart of the patient for providing a sufficient amount of energy for defibrillation. The lead includes a lead body that extends from the mid-auxiliary position along an inter-costal area between ribs and oriented with the coil electrode(s) extending along the sternum (e.g., over the sternum or parasternally within one to three centimeters from the sternum). A proximal end the coil electrodes may be located proximate to the xiphoid process. [0075] Figure 4 shows a block diagram of an exemplary S-IMD 400 that is configured to be implanted into the patient. The S-IMD 400 may treat both fast and slow arrhythmias with stimulation therapy, including cardioversion, pacing stimulation, an implantable cardioverter defibrillator, suspend tachycardia detection, tachyarrhythmia therapy, and/or the like. [0076] The S-IMD 400 has a housing 401 to hold the electronic/computing components. The housing 401 (which is often referred to as the "can," "case," "encasing," or "case electrode") may be programmably selected to act as the return electrode for certain stimulus modes. The housing 401 further includes a connector (not shown) with a plurality of terminals 300-310. The terminals may be connected to electrodes that are located in various locations within and about the heart. The type and location of each electrode may vary. For example, the 15662WOO1 (013-0610PCT1) 23 PATENT electrodes may include various combinations of ring, tip, coil, shocking electrodes, and the like. [0077] The S-IMD 400 includes a programmable microcontroller 320 that controls various operations of the S-IMD 400, including cardiac monitoring and stimulation therapy. The microcontroller 320 includes a microprocessor (or equivalent control circuitry), one or more processors, RAM and/or ROM memory, logic and timing circuitry, state machine circuitry, and I/O circuitry. The S-IMD 400 further includes a ventricular pulse generator 322 that generates stimulation pulses for connecting the desired electrodes to the appropriate I/O circuits, thereby facilitating electrode programmability. The switch 326 is controlled by a control signal 328 from the microcontroller 320. [0078] A pulse generator 322 is illustrated in Figure 4. Optionally, the S- IMD 400 may include multiple pulse generators, similar to the pulse generator 322, where each pulse generator is coupled to one or more electrodes and controlled by the microcontroller 320 to deliver select stimulus pulse(s) to the corresponding one or more electrodes. The S-IMD 400 includes sensing circuit 344 selectively coupled to one or more electrodes that perform sensing operations, through the switch 326 to detect the presence of cardiac activity in the chamber of the heart 411. The output of the sensing circuit 344 is connected to the microcontroller 320 which, in turn, triggers, or inhibits the pulse generator 322 in response to the absence or presence of cardiac activity. The sensing circuit 344 receives a control signal 346 from the microcontroller 320 for purposes of controlling the gain, threshold, polarization charge removal circuitry (not shown), and the timing of any blocking circuitry (not shown) coupled to the inputs of the sensing circuit 344. [0079] In the example of Figure 4, the sensing circuit 344 is illustrated. Optionally, the S-IMD 400 may include multiple sensing circuits 344, where each sensing circuit is coupled to one or more electrodes and controlled by the microcontroller 320 to sense electrical activity detected at the corresponding one 15662WOO1 (013-0610PCT1) 24 PATENT or more electrodes. The sensing circuit 344 may operate in a unipolar sensing configuration or a bipolar sensing configuration. [0080] The S-IMD 400 further includes an analog-to-digital (A/D) data acquisition system (DAS) 350 coupled to one or more electrodes via the switch 326 to sample cardiac signals across any pair of desired electrodes. The A/D converter 350 is configured to acquire intracardiac electrogram signals, convert the raw analog data into digital data and store the digital data for later processing and/or telemetric transmission to an external device 402 (e.g., a programmer, local transceiver, or a diagnostic system analyzer). The A/D converter 350 is controlled by a control signal 356 from the microcontroller 320. [0081] The switch 326 may be coupled to an LV lead having multiple LV electrodes, at least one of the LV electrodes configured to be located proximate to the LV site corresponding to the pacing site and to deliver the burst pacing therapy. The switch 326 may be further coupled to a second lead with at least one of a superior vena cava (SVC) coil electrode or an RV coil electrode, the shock vector including a CAN of the S-IMD and at least one of the SVC coil electrode or the RV coil electrode. [0082] The microcontroller 320 is operably coupled to a memory 360 by a suitable data/address bus 362. The programmable operating parameters used by the microcontroller 320 are stored in the memory 360 and used to customize the operation of the S-IMD 400 to suit the needs of a particular patient. The operating parameters of the S-IMD 400 may be non-invasively programmed into the memory 360 through a telemetry circuit 364 in telemetric communication via communication link 366 (e.g., MICS, Bluetooth low energy, and/or the like) with the external device 402. [0083] The S-IMD 400 can further include one or more physiological sensors 370. Such sensors are commonly referred to as "rate-responsive" 15662WOO1 (013-0610PCT1) 25 PATENT sensors because they are typically used to adjust pacing stimulation rates according to the exercise state of the patient. However, the physiological sensor 370 may further be used to detect changes in cardiac output, changes in the physiological condition of the heart, or diurnal changes in activity (e.g., detecting sleep and wake states). Signals generated by the physiological sensors 370 are passed to the microcontroller 320 for analysis. While shown as being included within the S-IMD 400, the physiological sensor(s) 370 may be external to the S- IMD 400, yet still, be implanted within or carried by the patient. Examples of physiological sensors might include sensors that, for example, sense respiration rate, pH of blood, ventricular gradient, activity, position/posture, minute ventilation, and/or the like. [0084] A battery 372 provides operating power to all of the components in the S-IMD 400. The battery 372 is capable of operating at low current drains for long periods of time and is capable of providing a high-current pulses (for electrolytic capacitor charging) when the patient requires a shock pulse (e.g., in excess of 2 A, at voltages above 2 V, for periods of 10 seconds or more). In one example, the electrolytic capacitor that receives the high-current pulses is an electrolytic capacitor manufactured using the process of Figure 1. In particular, the electrolytic capacitor can withstand higher voltages of up to 950 Volts with multiple continuous pulses above 300 times without failure. The battery 372 also desirably has a predictable discharge characteristic so that elective replacement time can be detected. As one example, the S-IMD 400 employs lithium/silver vanadium oxide batteries. [0085] The S-IMD 400 further includes an impedance measuring circuit 374, which can be used for many things, including sensing respiration phase. The impedance measuring circuit 374 is coupled to the switch 326 so that any desired electrode and/or terminal may be used to measure impedance in connection with monitoring respiration phase. The S-IMD 400 is further equipped with a 15662WOO1 (013-0610PCT1) 26 PATENT communication modem (modulator/demodulator) 340 to enable wireless communication with other devices, implanted devices and/or external devices. In one implementation, the communication modem 340 may use high frequency modulation of a signal transmitted between a pair of electrodes. As one example, the signals may be transmitted in a high frequency range of approximately 10-80 kHz, as such signals travel through the body tissue and fluids without stimulating the heart or being felt by the patient. [0086] The microcontroller 320 further controls a shocking circuit 380 by way of a timing control 332. The shocking circuit 380 generates shocking pulses, such as MV shocks, LV shocks, etc., as controlled by the microcontroller 320. In accordance with some embodiments, the shocking circuit 380 includes a single change storage electrolytic capacitor that delivers entire phase I and phase II therapies. In one example, the electrolytic capacitor is manufactured utilizing the process of Figure 1. The shocking circuit 380 is controlled by the microcontroller 320 by a control signal 382. [0087] Although not shown, the microcontroller 320 may further include other dedicated circuitry and/or firmware/software components that assist in monitoring various conditions of the patient's heart and managing pacing therapies. The microcontroller 320 further includes a timing control 332, an arrhythmia detector 334, a morphology detector 336 and multi-phase VF therapy controller 333. The timing control 332 is used to control various timing parameters, such as stimulation pulses (e.g., pacing rate, atria-ventricular (AV) delay, atrial interconduction (A-A) delay, ventricular interconduction (V-V) delay, etc.) as well as to keep track of the timing of RR-intervals, refractory periods, blanking intervals, noise detection windows, evoked response windows, alert intervals, marker channel timing, and the like. The timing control 332 controls a timing for delivering the phase I, II and III therapies in a coordinated manner. The timing control 332 controls the phase II and III therapy timed relative to the MV shocks to cooperate 15662WOO1 (013-0610PCT1) 27 PATENT with the MV shocks to terminate fibrillation waves of the ventricular arrhythmia episode and to reduce a defibrillation threshold of the heart below a shock-only defibrillation threshold. [0088] The arrhythmia detector 334 is configured to apply one or more arrhythmia detection algorithms for detecting arrhythmia conditions. By way of example, the arrhythmia detector 334 may apply various VF detection algorithms. The arrhythmia detector 334 is configured to declare a ventricular fibrillation (VF) episode based on the cardiac events. [0089] The therapy controller 333 is configured to perform the operations described herein. The therapy controller 333 is configured to identify a multi-phase VF therapy based on the ventricular fibrillation episode, the multi-phase VF therapy including MV shocks, LV shocks and a pacing therapy. The therapy controller 333 is configured to manage delivery of the burst pacing therapy at a pacing site in a coordinated manner after the MV and LV shocks. The pacing site is located at one of a left ventricular (LV) site or a right ventricular (RV) site. The therapy controller 333 is configured to manage delivery of the MV shock along a shocking vector between shocking electrodes. [0090] The therapy controller 333 is further configured to analyze a timing of VF beats to obtain at least one of a VF cycle length (CL) or variation and to determine at least one of a number of pulses in a pulse train of the burst pacing therapy or a duration of pulse train of the burst pacing therapy based on at least one of the VF cycle length or variation. The therapy controller 333 may be further configured to set a timing delay to time the burst pacing therapy such that one or more of pulses therefrom occur during a period of time in which a local tissue region surrounding the pacing site is excitable and not refractory. The therapy controller 333 may be configured to set a frequency of the burst pacing therapy at a high frequency relative to a cycle length of non-fibrillation arrhythmias. 15662WOO1 (013-0610PCT1) 28 PATENT [0091] In accordance with embodiments, the S-IMD 400 may represent a subcutaneous implantable cardioverter defibrillator (SICD). Optionally, the communication modem 340 may be configured to wirelessly communicate with a leadless pacemaker, such as to pass timing information there between. The SICD may deliver phase I and II therapies, while the phase III pacing therapy may be delivered by the S-CID or the leadless pacemaker. The communication modem 340 may transmit timing information to a leadless pacemaker such as when sending an instruction for the leadless pacemaker to deliver pacing therapies in connection with embodiments herein. The communication modem 340 may receive timing information from a leadless pacemaker such as when receiving a direction from the leadless pacemaker that the low voltage therapy has been delivered or is currently being delivered and that SICD should now deliver the HV shock(s). [0092] Figure 5 illustrates an image captured by a scanning electron microscope (SEM) of a metal foil 500 that is formed without using the disclosed process as described in relation to Figure 1. In particular, no vibrational energy or forces were applied to the metal foil during the manufacturing process of the metal foil 500. As a result, the thickness 502 is significantly varied from an initial 115 microns to 109.8 microns. [0093] Meanwhile, Figure 6 illustrates an image captured by a SEM of a metal foil 600 that utilized the etching process of Figure 1 that uses vibrational energy during presoaking, etching, and tunnel widening to form an anode, or electrolytic material. As a result of using the process of Figure 1 the metal foil 600 has a thickness 602 retains closer to the original thickness of the material of around 115 microns and therefore, allows for less thinning during etching. In addition, a more uniform surface profile is provided as compared to the metal foil 500 of Figure 5. Having a more uniform surface profile promotes less stress/strain concentration when the metal foil 600 is manipulated during capacitor 15662WOO1 (013-0610PCT1) 29 PATENT manufacturing, promoting both in higher manufacturing yield, and lower defects in manufactured product, due to more mechanically robust constituent anodes as well as somewhat reduced probability of particle generation which can result in latent failures. [0094] Additionally, the method as described in relation to Figure 1 shows an increase in the metal foil capacitance as much as 6% compared to only using a moly acid process in that does not utilize vibration during just the etching process. The use of the method Figure 1 of using vibrational energy during just the etching process also shows an increase in energy density of a resulting capacitor by up to 6%. Because of the increase in energy density, alternatively to achieve the same energy density currently provided without using vibrational energy as provided in the process of Figure 1, lower etching coulombs could be applied to maintain the same metal foil capacitance to produce stronger metal foil and thus reduce manufacturing costs. With the use of the moly acid process with vibrational (energy) excitation applied to the metal foil in the various steps of etch and widening, a 13% to 15% increase in metal foil capacitance has been observed over not using vibrational energy during the manufacturing process of Figure 1. Thus, all problems described herein are overcome and an improved manufacturing process for forming electrolytic materials and in particular anodes for a capacitor is provided. [0095] The average sheet capacitance of a control without the molybdic acid additive and the 5 to 20 second presoak was 325 microF and the average sheet capacitance using the molybdic acid additive at 400 ppm and a 9 second presoak with physical excitation only during etch and presoak was 373 microF indicating a 12.8 % increase in metal foil capacitance. Capacitors built using the method described herein showed a 11 to 12 % increase in delivered energy over the control. The capacitor pairs built with the method described herein allowed for a 40J cap pair at nominal voltage versus 36J and a 44.5J cap pair at safety shock 15662WOO1 (013-0610PCT1) 30 PATENT over 40J. This could allow for higher longevity if applied or higher current densities above 6J/cc for future designs. Lastly, the increase in metal foil capacitance allows for more degrees of freedom of design for other ICD device components and still maintain overall dimensions and electrical outputs. When physical excitation was used only at widening, a 1.5% increase in metal foil capacitance was found over not using the vibrational excitation. Closing [0096] It should be clearly understood that the various arrangements and processes broadly described and illustrated with respect to the Figures, and/or one or more individual components or elements of such arrangements and/or one or more process operations associated of such processes, can be employed independently from or together with one or more other components, elements and/or process operations described and illustrated herein. Accordingly, while various arrangements and processes are broadly contemplated, described and illustrated herein, it should be understood that they are provided merely in illustrative and non-restrictive fashion, and furthermore can be regarded as but mere examples of possible working environments in which one or more arrangements or processes may function or operate. [0097] It is to be understood that the subject matter described herein is not limited in its application to the details of construction and the arrangement of components set forth in the description herein or illustrated in the drawings hereof. The subject matter described herein is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 15662WOO1 (013-0610PCT1) 31 PATENT [0098] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings herein without departing from its scope. While the dimensions, types of materials and coatings described herein are intended to define various parameters, they are by no means limiting and are illustrative in nature. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the embodiments should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects or order of execution on their acts. 15662WOO1 (013-0610PCT1) 32 PATENT

Claims

WHAT IS CLAIMED IS: 1. A method for manufacturing an electrolytic capacitor for an implantable medical device comprising: placing a metal foil within an etch solution; etching tunnels in the metal foil during an electrochemical reaction; and vibrating the metal foil while the metal foil is within the etch solution.

2. The method of claim 1, wherein the method further comprises presoaking the metal foil in the etch solution for a determined period of time before etching the tunnels in the metal foil; and wherein the vibrating of the metal foil occurs either during the presoaking or during the etching.

3. The method of claim 2, wherein the determined period of time is between 5 and 20 seconds.

4. The method of claim 2, wherein the method further comprises widening the tunnels in the metal foil after etching the tunnels in the metal foil, and wherein the vibrating of the metal foil occurs during at least one of the presoaking, the etching, or the widening.

5. The method of claim 1, wherein vibrating the metal foil includes providing a linear displacement of the metal foil or a non-linear displacement of the metal foil.

6. The method of claim 1, wherein vibrating the metal foil comprises at least one of vibrating the metal foil directly or vibrating the metal foil indirectly.

7. The method of claim 6, wherein vibrating the metal foil directly includes engaging the metal foil with a probe and providing vibrational energy. 15662WOO1 (013-0610PCT1) 33 PATENT

8. The method of claim 6, wherein vibrating the metal foil indirectly includes vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil.

9. The method of claim 1, wherein the metal foil is an aluminum foil and the etch solution is a chloride solution with an oxidizer that is at least 5% by weight of the chloride solution.

10. The method of claim 8, wherein the etch solution also includes 10 to 4000 ppm molybdic acid.

11. A method for manufacturing an electrolytic capacitor for an implantable medical device comprising: presoaking an aluminum foil in an etch solution that includes molybdenum for a determined period of time; etching the aluminum foil within the etch solution to form tunnels within the aluminum foil; widening the tunnels of the aluminum foil; and wherein vibrational energy is applied to the aluminum foil during at least one of the presoaking, etching or widening.

12. The method of claim 11, wherein vibrating the aluminum foil comprises at least one of vibrating the aluminum foil directly or vibrating the metal foil indirectly.

13. The method of claim 12, wherein vibrating the aluminum foil directly includes engaging the metal foil with a probe and providing vibrational energy at a linear displacement or a non-linear displacement. 15662WOO1 (013-0610PCT1) 34 PATENT

14. The method of claim 12, wherein vibrating the aluminum foil indirectly includes vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil.

15. A method for manufacturing an electrolytic capacitor for an implantable medical device comprising: presoaking an aluminum foil in an etch solution that includes molybdenum for a determined period of time; applying a determined current density to the etch solution to etch to form tunnels within the aluminum foil; widening the tunnels of the aluminum foil to form an electrolytic material; and applying vibrational energy to the aluminum foil during each of the presoaking, applying, and widening.

16. The method of claim 15, wherein the determined period of time is between 5 and 20 seconds and the determined current density is between 0.25 to 0.3 amps/cm².

17. The method of claim 15, further comprising: forming an electrolytic capacitor having an anode formed from the electrolytic material.

18. The method of claim 15, wherein vibrating the aluminum foil comprises at least one of vibrating the aluminum foil directly or vibrating the metal foil indirectly. 15662WOO1 (013-0610PCT1) 35 PATENT

19. The method of claim 15, wherein applying vibrational energy includes providing either linear displacement on the aluminum foil or non-linear displacement on the aluminum foil.

20. The method of claim 18, wherein vibrating the aluminum foil indirectly includes vibrating a clip coupled to the metal foil or vibrating a foil holder that holds the metal foil. 15662WOO1 (013-0610PCT1) 36 PATENT