Patent Publication Number: US-11658206-B2

Title: Deep trench structure for a capacitive device

Description:
BACKGROUND 
     Integrated circuits may be fabricated on a semiconductor wafer. Semiconductor wafers can be stacked or bonded on top of each other to form what is referred to as a three-dimensional integrated circuit. Some semiconductor wafers include micro-electromechanical-system (MEMS) devices, which involves the process of forming micro-structures with dimensions in the micrometer scale (one millionth of a meter). Typically, MEMS devices are built on silicon wafers and realized in thin films of materials. Examples of MEMS applications include motion sensors, accelerometers, gyroscopes, and humidity sensors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    is a diagram of an example environment in which systems and/or methods described herein may be implemented. 
         FIGS.  2 ,  3 ,  4 A, and  4 B  are diagrams of an example capacitive device described herein. 
         FIGS.  5 A- 5 K  are diagrams of an example implementation described herein. 
         FIG.  6    is a diagram of example components of one or more devices of  FIG.  1   . 
         FIG.  7    is a flowchart of an example process relating to forming a capacitive device described herein. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     A micro-electromechanical-system (MEMS) relative humidity sensor device is a MEMS device that may include one or more capacitive devices. A capacitive device may be a capacitor or may be a device that includes a plurality of capacitive elements electrically connected in parallel. A dielectric sensor may be placed between electrodes of a capacitor or a capacitive element. The dielectric sensor may be formed of a material having a dielectric constant that changes based on humidity. Changes in humidity cause a change in the dielectric constant of the dielectric sensor, which changes the capacitance of the capacitor or the capacitive element. The changes in capacitance can be converted to a measurement of relative humidity. 
     A dielectric sensor of a capacitor or a capacitive element may be formed in a trench between two structures on which the electrodes are formed. The trench may formed by etching through one or more layers down to a metal etch-stop layer. However, the use of the metal etch-stop layer may reduce the depth of the trench, which reduces the size of the dielectric sensor and decreases the capacitance of the capacitor or the capacitive element. This may reduce the humidity-sensing performance of the capacitor or the capacitive element. Moreover, parasitic capacitance resulting from the conductivity of the metal etch-stop layer may further reduce the humidity-sensing performance of the capacitor or the capacitive element. 
     Some implementations described herein provide a deep trench structure for a capacitive device. In some implementations, one or more metal etch-stop layers may be omitted from the capacitive device such that the deep trench structure may be formed between electrodes of the capacitive device down to (and partially in) an interlayer dielectric (ILD) layer of the capacitive device. In this way, the deep trench structure may be formed to a depth and/or an aspect ratio that increases the volume of the deep trench structure relative to a trench structure formed using a metal etch-stop layer. Thus, the deep trench structure is capable of being filled with a greater amount of dielectric material, which increases the capacitance value of the capacitive device. Moreover, the parasitic capacitance of the capacitive device may be decreased by omitting the metal etch-stop layer. Accordingly, the deep trench structure (and the omission of the metal etch-stop layer) may increase the sensitivity of the capacitive device, may increase the humidity-sensing performance of the capacitive device, and/or may increase the performance of devices (e.g., MEMS devices and/or other types of semiconductor devices) and/or integrated circuits in which the capacitive device is included. 
       FIG.  1    is a diagram of an example environment  100  in which systems and/or methods described herein may be implemented. As shown in  FIG.  1   , environment  100  may include a plurality of semiconductor processing tools  102 - 112 . The plurality of semiconductor processing tools  102 - 112  may include a deposition tool  102 , an exposure tool  104 , a developer tool  106 , an etching tool  108 , a plating tool  110 , a wafer/die transport tool  112 , and/or another type of semiconductor processing tool. The plurality of semiconductor processing tools  102 - 112  included in example environment  100  may be included in a semiconductor clean room, a semiconductor foundry, a semiconductor processing and/or manufacturing facility, and/or the like. 
     The deposition tool  102  is a semiconductor processing tool that includes a semiconductor processing chamber and one or more devices capable of depositing various types of materials onto a substrate. In some implementations, the deposition tool  102  includes a spin coating tool that is capable of depositing a photoresist layer on a substrate such as a wafer. In some implementations, the deposition tool  102  includes a chemical vapor deposition (CVD) tool such as a plasma-enhanced CVD (PECVD) tool, a high-density plasma CVD (HDP-CVD) tool, a sub-atmospheric CVD (SACVD) tool, an atomic layer deposition (ALD) tool, a plasma-enhanced atomic layer deposition (PEALD) tool, or another type of CVD tool. In some implementations, the deposition tool  102  includes a physical vapor deposition (PVD) tool, such as a sputtering tool or another type of PVD tool. In some implementations, the example environment  100  includes a plurality of types of deposition tools  102 . 
     The exposure tool  104  is a semiconductor processing tool that is capable of exposing a photoresist layer to a radiation source, such as an ultraviolet light (UV) source (e.g., a deep UV light source, an extreme UV light source, and/or the like), an x-ray source, and/or the like. The exposure tool  104  may expose a photoresist layer to the radiation source to transfer a pattern from a photomask to the photoresist layer. The pattern may include one or more semiconductor device layer patterns for forming one or more semiconductor devices, may include a pattern for forming one or more structures of a semiconductor device, may include a pattern for etching various portions of a semiconductor device, and/or the like. In some implementations, the exposure tool  104  includes a scanner, a stepper, or a similar type of exposure tool. 
     The developer tool  106  is a semiconductor processing tool that is capable of developing a photoresist layer that has been exposed to a radiation source to develop a pattern transferred to the photoresist layer from the exposure tool  104 . In some implementations, the developer tool  106  develops a pattern by removing unexposed portions of a photoresist layer. In some implementations, the developer tool  106  develops a pattern by removing exposed portions of a photoresist layer. In some implementations, the developer tool  106  develops a pattern by dissolving exposed or unexposed portions of a photoresist layer through the use of a chemical developer. 
     The etching tool  108  is a semiconductor processing tool that is capable of etching various types of materials of a substrate, wafer, or semiconductor device. For example, the etch tool  108  may include a wet etch tool, a dry etch tool, and/or the like. In some implementations, the etch tool  108  includes a chamber that is filled with an etchant, and the substrate is placed in the chamber for a particular time period to remove particular amounts of one or more portions of the substrate. In some implementations, the etch tool  108  may etch one or more portions of a the substrate using a plasma etch or a plasma-assisted etch, which may involve using an ionized gas to isotropically or directionally etch the one or more portions. 
     The plating tool  110  is a semiconductor processing tool that is capable of plating a substrate (e.g., a wafer, a semiconductor device, and/or the like) or a portion thereof with one or more metals. For example, the plating tool  110  may include a copper electroplating device, an aluminum electroplating device, a nickel electroplating device, a tin electroplating device, a compound material or alloy (e.g., tin-silver, tin-lead, and/or the like) electroplating device, and/or an electroplating device for one or more other types of conductive materials, metals, and/or the like. 
     Wafer/die transport tool  112  includes a mobile robot, a robot arm, a tram or rail car, an overhead hoist transfer (OHT) vehicle, and/or another type of device that are used to transport wafers and/or dies between semiconductor processing tools  102 - 110  and/or to and from other locations such as a wafer rack, a storage room, and/or the like. In some implementations, wafer/die transport tool  112  may be a programmed device to travel a particular path and/or may operate semi-autonomously or autonomously. 
     The number and arrangement of devices shown in  FIG.  1    are provided as one or more examples. In practice, there may be additional devices, fewer devices, different devices, or differently arranged devices than those shown in  FIG.  1   . Furthermore, two or more devices shown in  FIG.  1    may be implemented within a single device, or a single device shown in  FIG.  1    may be implemented as multiple, distributed devices. Additionally, or alternatively, a set of devices (e.g., one or more devices) of environment  100  may perform one or more functions described as being performed by another set of devices of environment  100 . 
       FIGS.  2 ,  3 ,  4 A, and  4 B  are diagrams of an example capacitive device  200 . Capacitive device  200  may be a capacitor or a device that includes a plurality of capacitive elements. In some implementations, capacitive device  200  may be included in another device or system, such as a MEMS device (e.g., a MEMS relative humidity sensor) or an integrated circuit, among other examples. 
       FIG.  2    shows a perspective view of the example capacitive device  200 . As shown in  FIG.  2   , the capacitive device  200  may include a substrate  202 . The substrate  202  may include a semiconductor die substrate, a semiconductor wafer, or another type of substrate in which semiconductor devices may be formed. In some implementations, the substrate  202  is formed of silicon, a material including silicon, a III-V compound semiconductor material such as gallium arsenide (GaAs), a silicon on insulator (SOI), or another type of semiconductor material. 
     As further shown in  FIG.  2   , the capacitive device  200  may include a first dielectric layer  204  above and/or on the substrate  202 . The dielectric layer  204  may be an interlayer dielectric (ILD) layer formed of an electrically insulating material that electrically insulates one or more structures or layers of the capacitive device  200  from other structures or layers of the capacitive device  200 . For example, the dielectric layer  204  may include tantalum nitride (TaN), silicon oxide (SiO x ), silicate glass, silicon oxycarbide, a silicon nitride (Si x N y ), and/or the like. 
     As further shown in  FIG.  2   , the capacitive device  200  may include a dielectric layer  206  above and/or on the dielectric layer  204 . The dielectric layer  206  may be an intermetal dielectric (IMD) layer formed of an electrically insulating material that electrically insulates one or more structures or layers of the capacitive device  200  from one or more metallization layers or metal structures of the capacitive device  200 . For example, the dielectric layer  206  may include tantalum nitride (TaN), silicon oxide (SiO x ), silicate glass, silicon oxycarbide, a silicon nitride (Si x N y ), and/or the like. 
     As further shown in  FIG.  2   , the capacitive device  200  may include a plurality of electrode structures  208  (e.g., electrode structure  208   a  and electrode structure  208   b ). The electrode structures  208  may be formed above and/or on the dielectric layer  206 . Each electrode structure  208  may be formed of a conductive metal capable of carrying an electric charge such as gold, aluminum, or silver, among other examples. An electrode structure  208  may be configured to store an electric charge. For example, the electrode structure  208   a  may be configured to store a positive charge (and thus, may be referred to as a positive charge electrode structure, a positive electrode structure, or a p-electrode structure), and the electrode structure  208   b  may be configured to store a negative charge (and thus, may be referred to as a negative charge electrode structure, a negative electrode structure, or an n-electrode structure). 
     Each electrode structure  208  may include an electrode pad  210  that electrically connects the electrode structure  208  to interconnects, vias, external contact pads, and/or other structures of the capacitive device  200  (or the device or system in which the capacitive device  200  is included). The electrode pad  210  may connect to a main structure  212 , which may also be referred to as a trunk line, a backbone, and/or the like. A plurality of electrodes  214  may branch off of the main structure  212 . 
     As further shown in  FIG.  2   . the main structure  212  and the electrodes  214  may form a comb structure in which the electrodes  214  are positioned or configured substantially perpendicular to the main structure  212 . Moreover, the electrodes  214  of the electrode structure  208   a  and the electrodes  214  of the electrode structure  208   b  may be interdigitated. In these examples, the electrodes  214  of the electrode structure  208   a  may be positioned or configured in the spaces between the electrodes  214  of the electrode structure  208   b , and the electrodes  214  of the electrode structure  208   b  may be positioned or configured in the spaces between the electrodes  214  of the electrode structure  208   a.    
     As further shown in  FIG.  2   , the capacitive device  200  may include a dielectric layer  216  above and/or on the dielectric layer  206 , and in between electrodes  214  of the electrode structures  208 . The dielectric layer  216  may be formed of a dielectric material that is sensitive to humidity, such as a polyimide layer or another polymer that is electrically insulating and sensitive to atmospheric humidity. The dielectric layer  216  may be sensitive to humidity in that the dielectric constant of the dielectric layer  216  changes based on the humidity of the environment in which the capacitive device  200  is located. 
     The dielectric layer  216  may be located or positioned in a non-conductive region  218  between respective pairs of electrodes  214 . Each pair of electrodes  214  may include an electrode  214  of the electrode structure  208   a  and an electrode  214  of the electrode structure  208   b . Thus, each pair of electrodes  214  may include a positive electrode (or positive charge electrode or p-electrode) and a negative electrode (or negative charge electrode or n-electrode). Accordingly, when the capacitive device  200  is in operation, an electric field may be generated in the dielectric layer  216  in a non-conductive region  218  between a pair of electrodes  214  as a result of positive charge stored by a positive electrode and negative charge stored by a negative electrode of the pair of electrodes  214 . A combination of a positive electrode, a negative electrode, and the dielectric layer  216  in a non-conductive region  218  between the positive electrode and the negative electrode may form a capacitive element  220  (or capacitor) of the capacitive device  200 . 
       FIG.  3    shows a cross-sectional view of a portion of the capacitive device  200  along line AA of  FIG.  2   . As shown in  FIG.  3   , the dielectric layer  204  may be located above and/or on the substrate  202 , the dielectric layer  206  may be located above and/or on the dielectric layer  204  without an intervening metallization layer between the dielectric layer  204  and the dielectric layer  206 , and the electrode pads  210  and the electrodes  214  of the electrode structures  208  may be located above and/or on the dielectric layer  206 . 
     As further shown in  FIG.  3   , deep trench structures  302  may be formed in the dielectric layer  206  between electrodes  214  such that the electrodes  214  are positioned on substantially trapezoidal shaped structures of the dielectric layer  206 . In particular, a deep trench structure  302  may be located in a non-conductive region  218  between a pair of electrodes  214  configured to store opposing charge of a capacitive element  220 . For example, a deep trench structure  302  may be located between an electrode  214   a  (e.g., configured to store a positive charge or a negative charge) and an electrode  214   b  (e.g., configured to store a type of charge that opposes the type of charge stored by electrode  214   a  so if electrode  214   a  stores a positive charge, electrode  214   b  stores a negative charge, or vice versa). The deep trench structures  302  of the capacitive device  200  may be filled with the dielectric layer  216 . The dielectric layer  216  may also be formed above and/or on the electrodes  214  to protect the electrodes from corrosion and other environmental effects. 
     In situations where the capacitive device  200  is included in a relative humidity sensing device (e.g., a MEMS relative humidity sensor device or another type of relative humidity sensing device), the dielectric layer  206  in the deep trench structure  302  may function as a humidity sensing layer. In these situations, the dielectric constant of the humidity sensing layer may be based on and/or may change based on humidity in the environment in which the relative humidity sensing device is located. Changes in the dielectric constant of the humidity sensing layer may result in changes to the electric field (and thus, the capacitance) between the electrodes  214   a  and  214   b . The relative humidity sensing device may include additional circuitry and/or components to measure the electric field and/or the capacitance between the electrodes  214   a  and  214   b  and/or convert the measurement to a relative humidity value. 
       FIG.  4 A  shows a cross-sectional close-up view  304  from a portion of the capacitive device  200  shown in  FIG.  3   . As shown in  FIG.  4 A , the dielectric layer  204  may be located above and/or on the substrate  202 , the dielectric layer  206  may be located above and/or on the dielectric layer  204  without an intervening metallization layer between the dielectric layer  204  and the dielectric layer  206 , the electrode pads  210  and the electrodes  214   a  and  214   b  of the capacitive element  220  may be located above and/or on the dielectric layer  206 , and the deep trench structure  302  may be located in and/or through the dielectric layer  206  between the electrodes  214   a  and  214   b.    
     As further shown in  FIG.  4 A , the capacitive device  200  may include one or more passivation layers, such as a passivation layer  402 , a passivation layer  404 , and a passivation layer  406 . The passivation layer  402  may be located above and/or on the electrodes  214   a  and  214   b . The passivation layer  402  may include an oxide material, such as a silicon oxide (SiO x ), a metallized oxide, or another type of oxide material. The passivation layer  402  may provide outside circuit passivation and may electrically isolate the electrodes  214   a  and  214   b  from other electrodes  214  and other circuits and/or devices of the capacitive device  200 . 
     The passivation layer  404  may be located above and/or on passivation layer  402  (e.g., which is above and/or on the electrodes  214   a  and  214   b ). The passivation layer  404  may include a nitride material, such as a silicon nitride (Si x N y ) or another type of nitride material. The passivation layer  404  may provide outside circuit passivation and may electrically isolate the electrodes  214   a  and  214   b  from other electrodes  214  and other circuits and/or devices of the capacitive device  200 . 
     The passivation layer  406  may be located above and/or on passivation layer  404  (e.g., which is above and/or on the electrodes  214   a  and  214   b ). Moreover, the passivation layer  406  may be located in the deep trench structure  302 . In particular, the passivation layer  406  may be located on the bottom of the deep trench structure  302  and on the sidewalls of the deep trench structure  302 . In this way, the passivation layer  406  in the deep trench structure  302  forms a trench liner that provides cavity passivation for the deep trench structure  302 . In some implementations, the passivation layer  406  includes a nitride material such as a silicon nitride (Si x N y ) or another type of nitride material. The dielectric layer  216  (e.g., the humidity sensing layer, in some implementations) may be located above and/or on the passivation layer  406  in the deep trench structure  302  and above the electrodes  214   a  and  214   b.    
     As further shown in  FIG.  4 A , the deep trench structure  302  may be located in a portion of the dielectric layer  204  below a top surface of the dielectric layer  204  referred to as an over-etch region  408 . The over-etch region  408  may be formed in the dielectric layer  204  during etching of the dielectric layer  206  when forming the deep trench structure  302  to achieve a particular trench depth of the deep trench structure  302 , to achieve a particular trench width of the deep trench structure  302 , and/or to achieve a particular aspect ratio for the deep trench structure  302 . In these examples, the bottom of the deep trench structure  302  is located in the over-etch region  408 , and therefore is located in a portion of the dielectric layer  204  below the top surface of the dielectric layer  204 . The passivation layer  406  may be formed on the dielectric layer  204  in the over-etch region  408  at the bottom of the deep trench structure  302  and at least partially below the top surface of the dielectric layer  204 . 
       FIG.  4 B  shows a cross-sectional close-up view  410  from a portion of the capacitive device  200  shown in  FIG.  4 A . As shown in  FIG.  4 B , various layers and/or structures of the capacitive device  200  may be formed to particular dimensions or dimensional ranges. In particular, the dielectric layer  206  may be formed to a height (or thickness) a, the electrodes  214   a  and  214   b  may be formed to a height (or thickness) b, the passivation layer  402  may be formed to a height (or thickness) c, the passivation layer  404  may be formed to a height (or thickness) d, and/or the passivation layer  404  may be formed to a height (or thickness) e. The dielectric layer  206  may be formed to the height a such that a particular depth f of the deep trench structure  302  may be achieved, such that a particular aspect ratio of the deep trench structure  302  may be achieved, and/or such that the volume within the deep trench structure  302  may be achieved. As an example, the height a of the dielectric layer  206  may be approximately 24,000 angstroms. 
     The electrodes  214   a  and  214   b  may each be formed to the height b such that a particular charge-storage capacity of the electrodes  214   a  and  214   b  may be achieved, such that a particular capacitance value for the capacitive device  200  and/or the capacitive element  220  may be achieved, and/or such that a particular capacitance value range for the capacitive device  200  and/or the capacitive element  220  may be achieved. As an example, the height b of the electrodes  214   a  and  214   b  may be approximately 8,000 angstroms. 
     The passivation layer  402  may be formed to the height c such that the passivation layer  402  may provide a particular amount of circuit passivation, such that a particular depth f of the deep trench structure  302  may be achieved, such that a particular aspect ratio of the deep trench structure  302  may be achieved, and/or such that the volume within the deep trench structure  302  may be achieved. As an example, the height c of the passivation layer  402  may be approximately 2,000 angstroms. 
     The passivation layer  404  may be formed to the height d such that the passivation layer  404  may provide a particular amount of circuit passivation, such that a particular depth f of the deep trench structure  302  may be achieved, such that a particular aspect ratio of the deep trench structure  302  may be achieved, and/or such that the volume within the deep trench structure  302  may be achieved. As an example, the height d of the passivation layer may be approximately 3,000 angstroms. 
     The passivation layer  406  may be formed to the height e such that the passivation layer  406  may provide a particular amount of trench passivation, such that a particular depth f of the deep trench structure  302  may be achieved, such that a particular aspect ratio of the deep trench structure  302  may be achieved, and/or such that the volume within the deep trench structure  302  may be achieved. As an example, the height e of the passivation layer may be approximately 4,000 angstroms. 
     The over-etch region  408  may be formed to the depth g such that a particular depth f of the deep trench structure  302  may be achieved, such that a particular aspect ratio of the deep trench structure  302  may be achieved, and/or such that the volume within the deep trench structure  302  may be achieved. As an example, the depth [[f]] g of the over-etch region  408  may be in a range of approximately 1,000 angstroms to approximately 9,000 angstroms. 
     The deep trench structure  302  may be formed to the depth f the width h, the sidewall angle j, and/or to a particular aspect ratio between the width h and the depth f such that one or more operational parameters and/or performance parameters for the capacitive device  200  and/or the capacitive element  220  are achieved. As an example, the deep trench structure  302  may be formed to the depth f the width h, the sidewall angle j, and/or to a particular aspect ratio between the width h and the depth f such that a particular capacitive value or capacitive value range (e.g., approximately 15,920 picofarads, approximately 15,650 picofarads to approximately 16,060 picofarads, among other examples) for the capacitive device  200  and/or the capacitive element  220  is achieved. As another example, the deep trench structure  302  may be formed to the depth f the width h, the sidewall angle j, and/or to a particular aspect ratio between the width h and the depth f such that a threshold amount of parasitic capacitive for the capacitive device  200  and/or the capacitive element  220  is achieved. As another example, the deep trench structure  302  may be formed to the depth f the width h, the sidewall angle j, and/or to a particular aspect ratio between the width h and the depth f such that a particular amount of volume (e.g., an amount of volume in which the dielectric layer  216  may be deposited) in the deep trench structure  302  is achieved. 
     An example depth f of the deep trench structure  302  may be in a range of approximately 42,000 angstroms to approximately 50,000 angstroms to achieve and/or satisfy one or more of the operational parameters and/or performance parameters described above. An example aspect ratio of the deep trench structure  302 , between the width h of the deep trench structure  302  and the depth f of the deep trench structure  302 , may be in a range of approximately 0.26 to approximately 0.38 to achieve and/or satisfy one or more of the operational parameters and/or the performance parameters described above. In some implementations, an example width h of the deep trench structure  302  is in a range of approximately 13,000 angstroms to approximately 15,000 angstroms to achieve and/or satisfy one or more of the operational parameters and/or performance parameters described above. In some implementations, an example width h of the deep trench structure  302  is greater than approximately 15,000 angstroms to achieve and/or satisfy one or more of the operational parameters and/or performance parameters described above. An example sidewall angle j of the sidewalls of the deep trench structure  302  may be in a range of approximately 7 degrees to approximately 8 degrees to achieve and/or satisfy one or more of the operational parameters and/or performance parameters described above. 
     The electrodes  214   a  and  214   b  may each be formed to a width k such that a particular charge-storage capacity of the electrodes  214   a  and  214   b  may be achieved, such that a particular capacitance value for the capacitive device  200  and/or the capacitive element  220  may be achieved, and/or such that a particular capacitance value range for the capacitive device  200  and/or the capacitive element  220  may be achieved. As an example, the width k of the electrodes  214   a  and  214   b  may be approximately 11,000 angstroms. 
     As indicated above,  FIGS.  2 ,  3 ,  4 A, and  4 B  are provided as one or more examples. Other examples may differ from what is described with regard to  FIGS.  2 ,  3 ,  4 A, and  4 B . 
       FIGS.  5 A- 5 K  are diagrams of an example implementation  500  described herein. In particular, example implementation  500  may be an example of forming the capacitive device  200  or a portion thereof. As shown in  FIG.  5 A , the portion of the capacitive device  200  may include a capacitive element  220 . As further shown in  FIG.  5 A , the capacitive device  200  may include the substrate  202  on which other layers and/or structures of the capacitive device  200  may be formed. 
     As shown in  FIG.  5 B , the dielectric layer  204  (e.g., the ILD layer) may be formed above and/or on the substrate  202 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the dielectric layer  204  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. 
     As shown in  FIG.  5 C , a first portion  206   a  of the dielectric layer  206  (e.g., the IMD layer) may be formed above and/or on the dielectric layer  204 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the first portion  206   a  of the dielectric layer  206  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. 
     As shown in  FIG.  5 D , a second portion  206   b  of the dielectric layer  206  (e.g., the IMD layer) may be formed above and/or on the first portion  206   a  of the dielectric layer  206 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the second portion  206   b  of the dielectric layer  206  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. 
     In some implementations, the dielectric layer  206  is composed of the first portion  206   a  and the second portion  206   b , and the first portion  206   a  and the second portion  206   b  are formed in separate deposition operations. In some implementations, the height (or thickness) of the first portion  206   a  and the height (or thickness) of the second portion  206   b  are the same height (or thickness). In some implementations, the height (or thickness) of the first portion  206   a  and the height (or thickness) of the second portion  206   b  are different heights (or different thicknesses). In some implementations, the dielectric layer  206  is composed of a single dielectric layer that is formed in a single deposition operation. The dielectric layer  206  may be formed above and/or on the dielectric layer  204  without an intervening metallization layer between the dielectric layer  204  and the dielectric layer  206 . 
     As shown in  FIG.  5 E , a metallization layer  502  may be formed above and/or on the dielectric layer  206 . A semiconductor processing tool may form or deposit the metallization layer  502  above and/or on the dielectric layer  206 . In some implementations, the deposition tool  102  deposits the metallization layer  502  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. In some implementations, the plating tool  110  deposits the metallization layer  502  using a plating technique such as electroplating (or electro-chemical deposition). In these examples, the plating tool  110  may apply a voltage across an anode formed of a plating material and a cathode (e.g., a substrate). The voltage causes a current to oxidize the anode, which causes the release of plating material ions from the anode. These plating material ions form a plating solution that travels through a plating bath toward the capacitive device  200 . The plating solution reaches the capacitive device  200  and deposits plating material ions onto the dielectric layer  206  to form the metallization layer  502 . 
     As shown in  FIG.  5 F , a plurality of portions of the metallization layer  502  may be etched through to the dielectric layer  206  to form the electrode pads  210  and the electrodes  214  of the electrode structures  208  included in the capacitive device  200 . For example, an electrode pad  210  and one or more electrodes  214   a  may be formed for an electrode structure  208   a , and another electrode pad  210  and one or more electrodes  214   b  may be formed for an electrode structure  208   b . The electrode pads  210  and the electrodes  214  may be formed by coating the metallization layer  502  with a photoresist (e.g., using the deposition tool  102 ), forming a pattern in the photoresist by exposing the photoresist to a radiation source (e.g., using the exposure tool  104 ), removing either the exposed portions or the non-exposed portions of the photoresist (e.g., using developer tool  106 ), and etching the plurality of portions of the metallization layer  502  to the dielectric layer  206  based on the pattern in the photoresist. In some implementations, the metallization layer  502  may be formed to a height (or thickness) such that the electrodes  214   a  and  214   b  satisfy a capacitance value parameter for the capacitive device  200 , and/or the metallization layer  502  may be etched so that a width of the electrodes  214   a  and  214   b  satisfy the capacitance value parameter for the capacitive device  200 . 
     As shown in  FIG.  5 G , a deep trench structure  302  may be formed in and/or through the metallization layer  502 , and in and/or through the dielectric layer  206 . Moreover, the deep trench structure  302  may be formed at least partially in and/or at least partially through the dielectric layer  204  such that an over-etch region  408  is formed below the top surface of the dielectric layer  204 . The deep trench structure  302  may be formed by coating the metallization layer  502  and/or the dielectric layer  206  with a photoresist (e.g., using the deposition tool  102 ), forming a pattern in the photoresist by exposing the photoresist to a radiation source (e.g., using the exposure tool  104 ), removing either the exposed portions or the non-exposed portions of the photoresist (e.g., using developer tool  106 ), and etching through the dielectric layer  206  and a portion of the dielectric layer  204  based on the pattern in the photoresist to form the deep trench structure  302  and the over-etch region  408 . In some implementations, the deep trench structure  302  may be formed to a depth, a width, an aspect ratio, and/or a sidewall angle such that the deep trench structure  302  satisfies a capacitance value parameter for the capacitive device  200 , such that the deep trench structure  302  satisfies a parasitic capacitance parameter for the capacitive device  200 , such that a particular volume of dielectric material can be filled in the deep trench structure  302 , and/or such that other operation parameters and/or performance parameters of the capacitive device  200  are achieved and/or satisfied. 
     As shown in  FIG.  5 H , a passivation layer  402  (e.g., a circuit passivation layer) may be formed above and/or on the electrodes  214   a  and  214   b . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the passivation layer  402  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. In some implementations, the passivation layer  402  may be formed to a height (or thickness) to satisfy a circuit passivation parameter for the capacitive device  200 . 
     As shown in  FIG.  5 I , a passivation layer  404  (e.g., a circuit passivation layer) may be formed above and/or on the passivation layer  402 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the passivation layer  404  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. In some implementations, the passivation layer  404  may be formed to a height (or thickness) to satisfy a circuit passivation parameter for the capacitive device  200 . 
     As shown in  FIG.  5 J , a passivation layer  406  (e.g., a trench passivation layer) may be formed above and/or on the passivation layer  404  and in the deep trench structure  302 . In particular, the passivation layer  406  may be formed on the bottom of the deep trench structure  302  in the over-etch region  408  and on the sidewalls of the deep trench structure  302 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the passivation layer  406  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. In some implementations, the passivation layer  406  may be formed to a height (or thickness) to satisfy a trench passivation parameter for the capacitive device  200 . 
     As shown in  FIG.  5 K , a dielectric layer  216  (e.g., a humidity sensing layer) may be formed above and/or on the passivation layer  406 , above and/or on the electrodes  214   a  and  214   b , and in the deep trench structure  302 . A semiconductor processing tool (e.g., the deposition tool  102 ) may deposit the dielectric layer  216  using a CVD technique, a PVD technique, an ALD technique, or another type of deposition technique. In some implementations, the dielectric layer  216  may be formed to a height (or thickness) and/or of a particular dielectric material to satisfy a humidity sensing capability parameter for the capacitive device  200 , to satisfy a capacitance value parameter for the capacitive device  200 , to satisfy a parasitic capacitance parameter for the capacitive device  200 , and/or to satisfy other operation parameters and/or performance parameters of the capacitive device  200 . 
     As indicated above,  FIGS.  5 A- 5 K  are provided as one or more examples. Other examples may differ from what is described with regard to  FIGS.  5 A- 5 K . In some implementations, the process of forming the capacitive device  200  may include additional techniques and/or procedures, fewer techniques and/or procedures, different techniques and/or procedures, or differently arranged techniques and/or procedures than those depicted in  FIG.  5 A- 5 K . 
       FIG.  6    is a diagram of example components of a device  600 . In some implementations, one or more of the semiconductor processing tools  102 - 112  may include one or more devices  600  and/or one or more components of device  600 . As shown in  FIG.  6   , device  600  may include a bus  610 , a processor  620 , a memory  630 , a storage component  640 , an input component  650 , an output component  660 , and a communication component  670 . 
     Bus  610  includes a component that enables wired and/or wireless communication among the components of device  600 . Processor  620  includes a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. Processor  620  is implemented in hardware, firmware, or a combination of hardware and software. In some implementations, processor  620  includes one or more processors capable of being programmed to perform a function. Memory  630  includes a random access memory, a read only memory, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). 
     Storage component  640  stores information and/or software related to the operation of device  600 . For example, storage component  640  may include a hard disk drive, a magnetic disk drive, an optical disk drive, a solid state disk drive, a compact disc, a digital versatile disc, and/or another type of non-transitory computer-readable medium. Input component  650  enables device  600  to receive input, such as user input and/or sensed inputs. For example, input component  650  may include a touch screen, a keyboard, a keypad, a mouse, a button, a microphone, a switch, a sensor, a global positioning system component, an accelerometer, a gyroscope, and/or an actuator. Output component  660  enables device  600  to provide output, such as via a display, a speaker, and/or one or more light-emitting diodes. Communication component  670  enables device  600  to communicate with other devices, such as via a wired connection and/or a wireless connection. For example, communication component  670  may include a receiver, a transmitter, a transceiver, a modem, a network interface card, and/or an antenna. 
     Device  600  may perform one or more processes described herein. For example, a non-transitory computer-readable medium (e.g., memory  630  and/or storage component  640 ) may store a set of instructions (e.g., one or more instructions, code, software code, and/or program code) for execution by processor  620 . Processor  620  may execute the set of instructions to perform one or more processes described herein. In some implementations, execution of the set of instructions, by one or more processors  620 , causes the one or more processors  620  and/or the device  600  to perform one or more processes described herein. In some implementations, hardwired circuitry may be used instead of or in combination with the instructions to perform one or more processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software. 
     The number and arrangement of components shown in  FIG.  6    are provided as an example. Device  600  may include additional components, fewer components, different components, or differently arranged components than those shown in  FIG.  6   . Additionally, or alternatively, a set of components (e.g., one or more components) of device  600  may perform one or more functions described as being performed by another set of components of device  600 . 
       FIG.  7    is a flowchart of an example process  700  associated with forming a capacitive device. In some implementations, one or more process blocks of  FIG.  7    may be performed by one or more semiconductor processing tools (e.g., one or more of the semiconductor processing tools  102 - 112 ). Additionally, or alternatively, one or more process blocks of  FIG.  7    may be performed by one or more components of device  600 , such as processor  620 , memory  630 , storage component  640 , input component  650 , output component  660 , and/or communication component  670 . 
     As shown in  FIG.  7   , process  700  may include forming a first dielectric layer on a substrate of a capacitive device (block  710 ). For example, a semiconductor processing tool (e.g., the deposition tool  102 ) may form a first dielectric layer  204  on a substrate  202  of a capacitive device  200 , as described above. 
     As further shown in  FIG.  7   , process  700  may include forming a second dielectric layer on the first dielectric layer (block  720 ). For example, a semiconductor processing tool (e.g., the deposition tool  102 ) may form a second dielectric layer  206  on the first dielectric layer  204 , as described above. 
     As further shown in  FIG.  7   , process  700  may include forming a metal layer on the second dielectric layer (block  730 ). For example, a semiconductor processing tool (e.g., the deposition tool  102 , the plating tool  110 , and/or another semiconductor processing tool) may form a metal layer  502  on the second dielectric layer  206 , as described above. 
     As further shown in  FIG.  7   , process  700  may include etching the metal layer to form a first electrode of the capacitive device, a first electrode pad, associated with the first electrode, of the capacitive device, a second electrode of the capacitive device, and a second electrode pad, associated with the second electrode, of the capacitive device (block  740 ). For example, one or more semiconductor processing tools (e.g., the deposition tool  102 , the exposure tool  104 , the developer tool  106 , the etching tool  108 , and/or another semiconductor processing tool) may etch the metal layer  502  to form a first electrode  214   a  of the capacitive device  200 , a first electrode pad  210  associated with the first electrode  214   a  of the capacitive device  200 , a second electrode  214   b  of the capacitive device  200 , and a second electrode pad  210  associated with the second electrode  214   b  of the capacitive device  200 , as described above. 
     As further shown in  FIG.  7   , process  700  may include etching through the second dielectric layer and into a portion of the first dielectric layer to form a deep trench structure between the first electrode and the second electrode (block  750 ). For example, one or more semiconductor processing tools (e.g., the deposition tool  102 , the exposure tool  104 , the developer tool  106 , the etching tool  108 , and/or another semiconductor processing tool) may etch through the second dielectric layer  206  and into a portion  408  of the first dielectric layer  204  to form a deep trench structure  302  between the first electrode  214   a  and the second electrode  214   b , as described above. 
     As further shown in  FIG.  7   , process  700  may include forming a humidity sensing layer in the deep trench structure (block  760 ). For example, the semiconductor processing tool (e.g., the deposition tool  102 ) may form a humidity sensing layer  216  in the deep trench structure  302 , as described above. 
     Process  700  may include additional implementations, such as any single implementation or any combination of implementations described below and/or in connection with one or more other processes described elsewhere herein. 
     In a first implementation, process  700  includes forming (e.g., using the deposition tool  102 ) a first electrical passivation layer  402  on the first electrode  214   a  and on the second electrode  214   b , forming (e.g., using the deposition tool  102 ) a second electrical passivation layer  404  on the first electrical passivation layer  402 , and forming (e.g., using the deposition tool  102 ) a trench passivation layer  406  on the second electrical passivation layer  404  and in the deep trench structure  302 . In a second implementation, alone or in combination with the first implementation, forming the humidity sensing layer  216  in the deep trench structure  302  includes forming the humidity sensing layer  216  over the trench passivation layer  406  in the deep trench structure  302 . 
     In a third implementation, alone or in combination with one or more of the first and second implementations, etching through the second dielectric layer  206  and into the portion of the first dielectric layer  204  to form the deep trench structure  302  includes etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  to a particular height such that the capacitive device  200  satisfies at least one of a capacitance value parameter or a parasitic capacitance parameter. In a fourth implementation, alone or in combination with one or more of the first through third implementations, etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  includes etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  to a particular width such that the capacitive device  200  satisfies at least one of a capacitance value parameter or a parasitic capacitance parameter. 
     In a fifth implementation, alone or in combination with one or more of the first through fourth implementations, etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  includes etching through the second dielectric layer  206  and into the portion of the first dielectric layer  204  to form the deep trench structure  302  to a particular aspect ratio such that the capacitive device  200  satisfies at least one of a capacitance value parameter or a parasitic capacitance parameter. In a sixth implementation, alone or in combination with one or more of the first through fifth implementations, etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  includes etching through the second dielectric layer  206  and into the portion  408  of the first dielectric layer  204  to form the deep trench structure  302  to a particular volume such that the capacitive device  200  satisfies at least one of a capacitance value parameter or a parasitic capacitance parameter. 
     In a seventh implementation, alone or in combination with one or more of the first through sixth implementations, etching the metal layer  502  to form the first electrode  214   a  and the second electrode  214   b  includes etching the metal layer  502  to form the first electrode  214   a  and the second electrode  214   b  to respective widths such that the capacitive device  200  satisfies a capacitance parameter. In an eighth implementation, alone or in combination with one or more of the first through seventh implementations, forming the second dielectric layer  206  on the first dielectric layer  204  includes forming the second dielectric layer  206  directly on the first dielectric layer  204  without an intervening metallization layer. 
     Although  FIG.  7    shows example blocks of process  700 , in some implementations, process  700  may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in  FIG.  7   . Additionally, or alternatively, two or more of the blocks of process  700  may be performed in parallel. 
     In this way, one or more metal etch-stop layers may be omitted from the capacitive device such that the deep trench structure may be formed between electrodes of the capacitive device down to (and partially in) an ILD layer of the capacitive device. In this way, the deep trench structure may be formed to a depth and/or an aspect ratio that increases the volume of the deep trench structure relative to a trench structure formed using a metal etch-stop layer. Thus, the deep trench structure is capable of being filled with a greater amount of dielectric material, which increases the capacitance value of the capacitive device. Moreover, the parasitic capacitance of the capacitive device may be decreased by omitting the metal etch-stop layer. Accordingly, the deep trench structure (and the omission of the metal etch-stop layer) may increase the sensitivity of the capacitive device, may increase the humidity-sensing performance of the capacitive device, and/or may increase the performance of devices (e.g., MEMS devices and/or other types of semiconductor devices) and/or integrated circuits in which the capacitive device is included. 
     As described in greater detail above, some implementations described herein provide a capacitive device. The capacitive device includes a first electrode and a second electrode. The capacitive device includes a deep trench structure between the first electrode and the second electrode. A bottom of the deep trench structure is in an over-etch region that is below a surface of an ILD layer. The ILD layer is below the first electrode and the second electrode. The capacitive device includes a dielectric layer in the deep trench structure. 
     As described in greater detail above, some implementations described herein provide a capacitive device. The capacitive device includes a positive charge electrode structure including a plurality of positive electrodes connected to a first electrode pad. The capacitive device includes a negative charge electrode structure including a plurality of negative electrodes connected to a second electrode pad. The capacitive device includes a plurality of deep trench structures. A deep trench structure, of the plurality of deep trench structures, is located between a pair of a positive electrode of the plurality of positive electrodes and a negative electrode of the plurality of negative electrodes. An aspect ratio, between a width of the deep trench structure and a height of the deep trench structure, is in a range of approximately 0.26 to approximately 0.38. The capacitive device includes a humidity sensing layer in the plurality of deep trench structures. 
     As described in greater detail above, some implementations described herein provide a method. The method includes forming a first dielectric layer on a substrate of a capacitive device. The method includes forming a second dielectric layer on the first dielectric layer. The method includes forming a metal layer on the second dielectric layer. The method includes etching the metal layer to form a first electrode of the capacitive device, a first electrode pad, associated with the first electrode, of the capacitive device, a second electrode of the capacitive device, and a second electrode pad, associated with the second electrode, of the capacitive device. The method includes etching through the second dielectric layer and into a portion of the first dielectric layer to form a deep trench structure between the first electrode and the second electrode. The method includes forming a humidity sensing layer in the deep trench structure. The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.