Patent Publication Number: US-11646262-B2

Title: Semiconductor device with horizontally arranged capacitor and method for fabricating the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a semiconductor device and a method for fabricating the semiconductor device, and more particularly, to a semiconductor device with a horizontally arranged capacitor and the method for fabricating the semiconductor device with the horizontally arranged capacitor. 
     DISCUSSION OF THE BACKGROUND 
     Semiconductor devices are used in a variety of electronic applications, such as personal computers, cellular telephones, digital cameras, and other electronic equipment. The dimensions of semiconductor devices are continuously being scaled down to meet the increasing demand of computing ability. However, a variety of issues arise during the scaling-down process, and such issues are continuously increasing. Therefore, challenges remain in achieving improved quality, yield, performance, and reliability and reduced complexity. 
     This Discussion of the Background section is provided for background information only. The statements in this Discussion of the Background are not an admission that the subject matter disclosed in this section constitutes prior art to the present disclosure, and no part of this Discussion of the Background section may be used as an admission that any part of this application, including this Discussion of the Background section, constitutes prior art to the present disclosure. 
     SUMMARY 
     One aspect of the present disclosure provides a semiconductor device including a first palm portion positioned above a substrate; a second palm portion positioned above the substrate and opposite to the first palm portion; a first finger portion arranged substantially in parallel with a main surface of the substrate, positioned between the first palm portion and the second palm portion, and connecting to the first palm portion; a second finger portion arranged substantially in parallel with the first finger portion, positioned between the first palm portion and the second palm portion, and connecting to the second palm portion; a capacitor insulation layer positioned between the first finger portion and the second finger portion; a first spacer positioned between the first palm portion and second finger portion; and a second spacer positioned between the second palm portion and the first finger portion. 
     In some embodiments, the semiconductor device includes a bottom conductive layer arranged substantially in parallel with the second finger portion, positioned between the first palm portion and the second palm portion, and connecting to the first palm portion. 
     In some embodiments, the semiconductor device includes a third spacer positioned between the bottom conductive layer and the second palm portion. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The first palm portion is positioned on the impurity region and contacting the impurity region. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The second palm portion is positioned on the impurity region and contacting the impurity region. 
     In some embodiments, the semiconductor device includes a stop layer arranged substantially in parallel with the capacitor insulation layer and positioned between the second finger portion and the bottom conductive layer. 
     In some embodiments, the semiconductor device includes a bottom conductive layer arranged substantially in parallel with the second finger portion, positioned between the first palm portion and the second palm portion, and connecting to the second palm portion. 
     In some embodiments, the semiconductor device includes a third spacer positioned between the bottom conductive layer and the first palm portion. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The first palm portion is positioned on the impurity region and contacting the impurity region. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The second palm portion is positioned on the impurity region and contacting the impurity region. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The first palm portion is electrically coupled to the impurity region through a bottom conductive layer. 
     In some embodiments, the semiconductor device includes an impurity region positioned in the substrate. The second palm portion is electrically coupled to the impurity region through a bottom conductive layer. 
     In some embodiments, the semiconductor device includes a buried insulation layer positioned in the substrate. The impurity region is positioned above the buried insulation layer. 
     In some embodiments, a thickness of the first finger portion and a thickness of the second finger portion are different. 
     In some embodiments, a width of the first finger portion and a width of the second finger portion are different. 
     In some embodiments, a width of the first spacer and a width of the second spacer are different. 
     In some embodiments, a thickness of the bottom conductive layer and a thickness of the second finger portion are different. 
     Another aspect of the present disclosure provides a method for fabricating a semiconductor device including providing a substrate; sequentially forming a first conductive layer, an insulation layer, and a second conductive layer over the substrate to configure a stack; patterning the stack to form a first recess and expose an impurity region in the substrate; forming a first spacer to cover a sidewall of the first conductive layer; forming a first palm portion in the first recess and connecting to the second conductive layer; patterning the stack to form a third recess, turn the second conductive layer into a first finger portion, and turn the first conductive layer into a second finger portion, wherein the third recess is opposite to the first palm portion; forming a second spacer to cover a sidewall of the first finger portion, wherein the second spacer is opposite to the first palm portion; and forming a second palm portion in the third recess and connecting to the second finger portion. 
     In some embodiments, the method for fabricating the semiconductor device includes a step of forming a bottom conductive layer substantially in parallel with a main surface of the substrate and connecting to the first palm portion. 
     In some embodiments, the bottom conductive layer and the second finger portion include a same material. 
     Due to the design of the semiconductor device of the present disclosure, the contact area of the capacitor structure may be increased. As a result, the performance of the semiconductor device may be improved. In addition, the process flow may be easily integrated with fin type transistors. 
     The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter, and form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. 
    
    
     
       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 should be 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    illustrates, in a flowchart diagram form, a method for fabricating a semiconductor device in accordance with one embodiment of the present disclosure; 
         FIGS.  2  to  14    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating the semiconductor device in accordance with one embodiment of the present disclosure; 
         FIGS.  15  to  18    illustrate, in schematic cross-sectional view diagrams, semiconductor devices in accordance with some embodiments of the present disclosure; 
         FIGS.  19  to  22    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating a semiconductor device in accordance with another embodiment of the present disclosure; 
         FIGS.  23  to  27    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating a semiconductor device in accordance with another embodiment of the present disclosure; 
         FIG.  28    illustrates, in a schematic cross-sectional view diagram, a semiconductor device in accordance with another embodiment of the present disclosure. 
     
    
    
     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. 
     It should be understood that when an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it can be directly connected to or coupled to another element or layer, or intervening elements or layers may be present. 
     It should be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. Unless indicated otherwise, these terms are only used to distinguish one element from another element. Thus, for example, a first element, a first component or a first section discussed below could be termed a second element, a second component or a second section without departing from the teachings of the present disclosure. 
     Unless the context indicates otherwise, terms such as “same,” “equal,” “planar,” or “coplanar,” as used herein when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to reflect this meaning For example, items described as “substantially the same,” “substantially equal,” or “substantially planar,” may be exactly the same, equal, or planar, or may be the same, equal, or planar within acceptable variations that may occur, for example, due to manufacturing processes. 
     In the present disclosure, a semiconductor device generally means a device which can function by utilizing semiconductor characteristics, and an electro-optic device, a light-emitting display device, a semiconductor circuit, and an electronic device are all included in the category of the semiconductor device. 
     It should be noted that, in the description of the present disclosure, above (or up) corresponds to the direction of the arrow of the direction Z, and below (or down) corresponds to the opposite direction of the arrow of the direction Z. 
       FIG.  1    illustrates, in a flowchart diagram form, a method  10  for fabricating a semiconductor device  1 A in accordance with one embodiment of the present disclosure.  FIGS.  2  to  14    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating the semiconductor device  1 A in accordance with one embodiment of the present disclosure. 
     It should be noted that the terms “forming,” “formed” and “form” may mean and include any method of creating, building, patterning, implanting, or depositing an element, a dopant or a material. Examples of forming methods may include, but are not limited to, atomic layer deposition, chemical vapor deposition, physical vapor deposition, sputtering, co-sputtering, spin coating, diffusing, depositing, growing, implantation, photolithography, dry etching and wet etching. 
     It should be noted that the functions or steps noted herein may occur in an order different from the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in a reversed order, depending upon the functionalities or steps involved. 
     With reference to  FIGS.  1  to  3   , at step S 11 , a substrate  101  may be provided, an impurity region  103  may be formed in the substrate  101 , and a bottom conductive layer  105  may be formed on the substrate  101 . 
     With reference to  FIG.  2   , the substrate  101  may be a bulk semiconductor substrate, a multi-layered or gradient substrate, or the like. The substrate  101  may include a semiconductor material, such as an elemental semiconductor including Si and Ge; a compound or alloy semiconductor including SiC, SiGe, GaAs, GaP, GaAsP, AlInAs, AlGaAs, GaInAs, InAs, GaInP, InP, InSb, or GaInAsP; or a combination thereof. The substrate  101  may be doped or undoped. 
     With reference to  FIG.  2   , the impurity region  103  may be formed in the substrate  101 . The top surface of the impurity region  103  may be substantially coplanar with the top surface of the substrate  101 . A photoresist layer may be formed over the substrate  101 . The photoresist layer may be patterned to expose the area where the impurity region  103  to be formed. The photoresist layer may be formed by using a spin-on technique and may be patterned using acceptable photolithography techniques. Once the photoresist layer is patterned, an n-type impurity or a p-type impurity implantation process may be performed, and the photoresist layer may act as a mask to substantially prevent impurities from being implanted into the covered area. After the implantation process, the photoresist layer may be removed, such as by an acceptable ashing process. 
     The n-type impurity implantation process may add impurities that contribute free electrons to an intrinsic semiconductor. In a silicon-containing substrate, examples of n-type dopants, i.e., impurities, include but are not limited to antimony, arsenic, or phosphorous. The p-type impurity implantation process may add impurities to an intrinsic semiconductor that creates deficiencies of valence electrons. In a silicon-containing substrate, examples of p-type dopants, i.e., impurities include but are not limited to boron, aluminum, gallium, or indium. The dopant concentration of the impurity region  103  may be between about 1E17 atoms/cm{circumflex over ( )}3 and between about 1E18 atoms/cm{circumflex over ( )}3. 
     It should be noted that, the term “about” modifying the quantity of an ingredient, component, or reactant of the present disclosure employed refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or solutions. Furthermore, variation can occur from inadvertent error in measuring procedures, differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods, and the like. In one aspect, the term “about” means within 10% of the reported numerical value. In another aspect, the term “about” means within 5% of the reported numerical value. Yet, in another aspect, the term “about” means within 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% of the reported numerical value. 
     With reference to  FIG.  2   , the bottom conductive layer  105  may be blanket deposited on the substrate  101  and may be electrically connected to the impurity region  103  by contacting the impurity region  103 . It should be noted that, in the current stage, the bottom conductive layer  105  may cover the whole substrate  101  in a top-view perspective (not shown). In some embodiments, the bottom conductive layer  105  may be formed of, for example, polycrystalline silicon, polycrystalline germanium, polycrystalline silicon germanium, or the like. The bottom conductive layer  105  may be doped or undoped. For example, the bottom conductive layer  105  may be doped with n-type dopants or p-type dopants. 
     In some embodiments, the bottom conductive layer  105  may be formed of, for example, tungsten, cobalt, zirconium, tantalum, titanium, aluminum, ruthenium, copper, metal carbides (e.g., tantalum carbide, titanium carbide, tantalum magnesium carbide), metal nitrides (e.g., titanium nitride), transition metal aluminides, or a combination thereof. In some embodiments, the bottom conductive layer  105  may be formed by, for example, chemical vapor deposition, plasma-enhanced chemical vapor deposition, sputtering, or other suitable deposition techniques. 
     With reference to  FIGS.  1  and  4   , at step S 13 , a stop layer  107  may be formed on the bottom conductive layer  105 , a plurality of first conductive layers  401 , a plurality of insulation layers  405 , and a plurality of second conductive layers  403  may be sequentially and alternatively formed on the stop layer  107  to configure a stack. 
     With reference to  FIG.  4   , the stop layer  107  may be blanket deposited on the bottom conductive layer  105 . In some embodiments, the stop layer  107  may be formed of, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like. In some embodiments, the stop layer  107  may be formed of, for example, a low-k material. The low-k material may have a dielectric constant less than 3.6. In some embodiments, the stop layer  107  may be formed of, for example, oxides, nitrides, oxynitrides, silicates (e.g., metal silicates), aluminates, titanates, nitrides, high-k materials, or any combination thereof. In some embodiments, the stop layer  107  may include multiple layers. For example, a layer of silicon oxide and a layer of high-k materials. 
     The high-k materials may have a dielectric constant greater than about 7.0 and may be a metal oxide or a silicate of Hf, Al, Zr, La, Mg, Ba, Ti, Pb, or a combination thereof. Examples of high-k materials include, but are not limited to, metal oxides such as hafnium oxide, hafnium silicon oxide, hafnium silicon oxynitride, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, zirconium silicon oxynitride, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate. The high-k materials may further include dopants such as, for example, lanthanum and aluminum. 
     In some embodiments, the stop layer  107  may be formed by atomic layer deposition, chemical vapor deposition, molecular-beam deposition, plasma-enhanced chemical vapor deposition, chemical solution deposition, the like, or a combination thereof. In some embodiments, the thickness of the stop layer  107  may vary depending on the deposition process as well as the composition and number of materials used. 
     With reference to  FIG.  4   , the plurality of first conductive layers  401 , the plurality of insulation layers  405 , and the plurality of second conductive layers  403  may be alternatively deposited. For brevity, clarity, and convenience of description, only one first conductive layer  401 , one second conductive layer  403 , and one insulation layer  405  are described. For example, the first conductive layer  401  may be blanket formed on the stop layer  107 . The insulation layer  405  may be blanket formed on the first conductive layer  401 . The second conductive layer  403  may be blanket formed on the insulation layer  405 . Another insulation layer  405  may be blanket formed on the second conductive layer  403 . Another first conductive layer  401  may be blanket formed on the other insulation layer  405 . Another insulation layer  405  and another second conductive layer  403  may be sequentially formed on the other first conductive layer  401 . Other first conductive layer  401 , second conductive layer  403 , and insulation layer  405  may be stacked with a similar manner. 
     It should be noted that the number of the first conductive layer  401 , the second conductive layer  403 , and the insulation layer  405  in  FIG.  4    are just for illustration purpose. The number of the first conductive layer  401 , the second conductive layer  403 , and the insulation layer  405  may be more or less than that illustrated in the  FIG.  4   . 
     In some embodiments, the first conductive layer  401  and the second conductive layer  403  may be formed of, for example, a group IV material, such as Si, Ge, SiGe, SiGeSn, or the like, or a group III-group V compound material, such as GaAs, GaP, GaAsP, AlInAs, AlGaAs, GaInAs, InAs, GaInP, InP, InSb, GaInAsP, or the like. In some embodiments, the first conductive layer  401  and the second conductive layer  403  include silicon. In some embodiments, the first conductive layer  401  and the second conductive layer  403  include carbon doped silicon (Si:C). This Si:C layer can be grown in the same chamber used for other epitaxy steps or in a dedicated Si:C epitaxy chamber. The Si:C can include carbon in the range of 0.2 to 3.0%. 
     In some embodiments, the first conductive layer  401  and the second conductive layer  403  may be formed of different materials. The difference in materials may allow for the different strains for the first conductive layer  401  and the second conductive layer  403 . For example, the first conductive layer  401  is a layer of Si 0.50 Ge 0.50  and second conductive layer  403  is a layer of Si. The first conductive layer  401  may have natural lattice constant larger than that of the second conductive layer  403 . Hence, the first conductive layer  401  may be compressively strained and the second conductive layer  403  may be tensilely strained. In some embodiments, the first conductive layer  401  and the bottom conductive layer  105  may be formed of a same material but is not limited thereto. In some embodiments, the second conductive layer  403  and the bottom conductive layer  105  may be formed of a same material but is not limited thereto. 
     In some embodiments, the first conductive layer  401  and the second conductive layer  403  may include epitaxial semiconductor materials grown from gaseous or liquid precursors. The first conductive layer  401  and the second conductive layer  403  may be formed by rapid thermal chemical vapor deposition, metal-organic chemical vapor deposition, molecular beam epitaxy, liquid phase epitaxy, vapor phase epitaxy, ultra-high-vacuum chemical vapor deposition, low-pressure chemical vapor deposition, limited reaction processing chemical vapor deposition, or the like. In some embodiments, first conductive layer  401  and the second conductive layer  403  may include a crystalline material. 
     In some embodiments, epitaxial silicon, SiGe, and/or carbon doped silicon (Si:C) may be doped during deposition (in-situ doped) by adding dopants, n-type dopants (e.g., phosphorus or arsenic) or p-type dopants (e.g., boron or gallium). The dopant concentration of the first conductive layer  401  and the second conductive layer  403  may be between about 1E19 cm{circumflex over ( )}−3 to 2E21 cm{circumflex over ( )}−3, or between 1E20 cm{circumflex over ( )}−3 and 1E21 cm{circumflex over ( )}−3. 
     In some embodiments, the gas source for the deposition of epitaxial semiconductor material includes a silicon containing gas source, a germanium containing gas source, or a combination thereof. For example, an epitaxial Si layer can be deposited from a silicon gas source that is selected from the group consisting of silane, disilane, trisilane, tetrasilane, hexachlorodisilane, tetrachlorosilane, dichlorosilane, trichlorosilane, methylsilane, dimethylsilane, ethylsilane, methyldisilane, dimethyldisilane, hexamethyldisilane and a combination thereof. 
     An epitaxial germanium layer may be deposited from a germanium gas source that is selected from the group consisting of germane, digermane, halogermane, dichlorogermane, trichlorogermane, tetrachlorogermane and a combination thereof. 
     An epitaxial silicon germanium alloy layer may be formed utilizing a combination of such gas sources. Carrier gases like hydrogen, nitrogen, helium and argon may be used. 
     In some embodiments, the first conductive layer  401  may be condensed using a thermal oxidation process, for example, that results in the Si in the SiGe layer (e.g., the first conductive layer  401 ) being consumed (by the oxidation process) while the Ge is driven down into the underlying layer. The thermal oxidation process may include, for example, exposing the initial SiGe layer to a temperature of from about 900° C. to about 1,200° C., e.g., about 1,100° C. for a duration from about 5 minutes to about 15 minutes, in O 2 . 
     In some embodiments, the thickness T 1  of the first conductive layer  401  may be less than the thickness T 2  of the second conductive layer  403 . In some embodiments, the first conductive layer  401  and the second conductive layer  403  may have thicknesses less than a critical thickness. In some embodiments, the second conductive layer  403  may have thicknesses in the range between about 6 nm and about 20 nm. The first conductive layer  401  may have thicknesses in the range between about 4 nm and about 10 nm. In some embodiments, the thickness T 1  of the first conductive layer  401  may be greater than or equal to the thickness T 2  of the second conductive layer  403 . In some embodiments, the thickness T 1  of the first conductive layer  401  may be greater than or equal to the thickness T 3  of the bottom conductive layer  105 . In some embodiments, the thickness T 1  of the first conductive layer  401  may be less than the thickness T 3  of the bottom conductive layer  105 . 
     With reference to  FIG.  4   , the insulation layer  405  may be formed of, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like. In some embodiments, the insulation layer  405  may be formed of, for example, a low-k material. In some embodiments, the insulation layer  405  may be formed of, for example, oxides, nitrides, oxynitrides, silicates (e.g., metal silicates), aluminates, titanates, nitrides, high-k materials, or any combination thereof. In some embodiments, the insulation layer  405  may include multiple layers. For example, a layer of silicon oxide and a layer of high-k materials. In some embodiments, the insulation layer  405  may be formed of a same material as the stop layer  107  but is not limited thereto. 
     The high-k materials may have a dielectric constant greater than about 7.0 and may be a metal oxide or a silicate of Hf, Al, Zr, La, 
     Mg, Ba, Ti, Pb, or a combination thereof. Examples of high-k materials include, but are not limited to, metal oxides such as hafnium oxide, hafnium silicon oxide, hafnium silicon oxynitride, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, zirconium silicon oxynitride, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate. The high-k materials may further include dopants such as, for example, lanthanum and aluminum. 
     In some embodiments, the insulation layer  405  may be formed by atomic layer deposition, chemical vapor deposition, molecular-beam deposition, plasma-enhanced chemical vapor deposition, chemical solution deposition, the like, or a combination thereof. In some embodiments, the thickness T 4  of the insulation layer  405  may be greater than or equal to the thickness T 5  of the stop layer  107 . In some embodiments, the thickness T 4  of the insulation layer  405  may be less than the thickness T 5  of the stop layer  107 . In some embodiments, the thickness of the insulation layer  405  may vary depending on the deposition process as well as the composition and number of materials used. 
     The bottom conductive layer  105 , the stop layer  107 , the plurality of first conductive layers  401 , the plurality of insulation layers  405 , and the plurality of second conductive layers  403  together configure a stack. 
     With reference to  FIG.  1    and  FIGS.  5  and  6   , at step S 15 , the stack may be patterned to form a first recess R 1 . 
     With reference to  FIG.  5   , a first mask layer  407  may be formed on the topmost layer of the stack (i.e., the second conductive layer  403  in the present embodiment). The first mask layer  407  may be line shape in a top-view perspective (not shown). The first mask layer  407  may be, for example, a hard mask layer formed of a material having etching selectivity to the first conductive layer  401 , the second conductive layer  403 , the insulation layer  405 , the stop layer  107 , and the bottom conductive layer  105 . In some embodiments, the first mask layer  407  may be formed of, for example, amorphous carbon, silicon borocarbonitride, silicon oxycarbonitride, or silicon oxycarbide. 
     With reference to  FIG.  6   , an etch process may be performed to the intermediate semiconductor device illustrated in  FIG.  5    to form the first recess R 1 . The etch process may be, for example, a reactive ion etch, a neutral beam etch, the like, or a combination thereof. The etch process may be anisotropic. After the etch process, the sidewalls of the plurality of first conductive layers  401  and the plurality of second conductive layers  403  may be exposed through the first recess R 1 . In some embodiments, the etch process may be a timed isotropic wet etch process. In some embodiments, the etch process may be a selective dry etch process. In some embodiments, the etch process may be a combination of dry and wet etch processes. 
     In some embodiments, the etch rate of the first conductive layer  401  may be faster than the etch rate of the second conductive layer  403  during the etch process. After the etch process, the width of the plurality of first conductive layers  401  may be shorter than the width of the plurality of second conductive layers  403  and the plurality of insulation layers  405 . The recesses adjacent to the plurality of first conductive layers  401  may be regarded as a plurality of dimples  241 D. This plurality of dimples  241 D may be the result of the plurality of first conductive layer  401  being etched laterally during the etch process. 
     With reference to  FIG.  1    and  FIGS.  7  and  8   , at step S 17 , a plurality of first spacers  241  may be formed to cover the sidewalls of the plurality of first conductive layers  401 . 
     With reference to  FIG.  7   , a layer of first dielectric material  409  may be conformally formed to the intermediate semiconductor device illustrated in  FIG.  7   . The layer of first dielectric material  409  may completely fill the plurality of dimples  241 D. In some embodiments, the first dielectric material  409  may be the same as the material of the stop layer  107  or the material of the insulation layer  405 , but is not limited thereto. In some embodiments, the first dielectric material  409  may be for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like. In some embodiments, the first dielectric material  409  may be formed of, for example, a low-k material. In some embodiments, the first dielectric material  409  may be formed of, for example, oxides, nitrides, oxynitrides, silicates (e.g., metal silicates), aluminates, titanates, nitrides, high-k materials, or any combination thereof. The layer of first dielectric material  409  may be formed by, for example, atomic layer deposition, chemical vapor deposition, plasma-enhanced chemical vapor deposition. 
     With reference to  FIG.  8   , an etch process, such as an anisotropic dry etch process, may be performed to remove portions of the layer of first dielectric material  409 . After the etch process, the first dielectric material  409  outside the plurality of dimples  241 D may be removed. The first dielectric material  409  remained in the plurality of dimples  241 D may be regarded as the plurality of first spacers  241 . The first recess R 1  may be turned into the second recess R 2 . The sidewalls of the plurality of second conductive layers  403  may be exposed through the second recess R 2 . In contrast, the sidewalls of the plurality of first conductive layers  401  may be covered by the plurality of first spacers  241  and may not exposed through the second recess R 2 . After the etch process, the first mask layer  407  may be removed. 
     In some embodiments, before the etch process, the first dielectric material  409  deposited outside the plurality of dimples  241 D may be transformed into a transformed dielectric material (not shown). In an embodiment, transformed dielectric material may have a different etch selectivity than the first dielectric material  409 . By altering the etch selectivity of the transformed dielectric material as compared to the first dielectric material  409 , the etch process to remove excess first dielectric material  409  from outside the plurality of dimples  241 D may be more easily controlled. In such situation, the etch process may be an isotropic etch process. Transformation may occur by plasma treatment, implantation, oxidation, or a combination thereof. The transformation process is sufficient to alter the etch selectivity of the first dielectric material  409  outside of the plurality of dimples  241 D, but does not affect mobility or degrade performance of the plurality of first conductive layers  401  and the plurality of second conductive layers  403 . 
     In some embodiments, the plurality of first conductive layers  401  may not be laterally etched during the etch process. In other words, the sidewall of the stack may be substantially vertical. Alternatively, a selective oxidation process may be performed to selectively form the plurality of first spacers  241  on the sidewalls of the plurality of first conductive layers  401 . The selective oxidation process may be a selective wet oxidation or selective dry oxidation. If a selective wet oxidation process is desired, a high-pressure steam oxidation process may be performed. The high-pressure steam oxidation may include performing the oxidation above an atmospheric pressure in a combined H 2 O/N-based environment at relatively low temperatures ranging, for example, from about 500° C. to about 700° C. If a selective dry oxidation process is desired, a oxidation may be performed at atmospheric pressure, e.g., approximately 10,1325 pascals (Pa) (e.g., in an O 2  or O 2 /N 2  based environment at temperatures ranging, for example, from about 600° C. to about 800° C. The selective oxidation process may be time-based such that the plurality of first spacers  241  having a desired width may be achieved. The width W 1  of the plurality of first spacers  241  may be between about 5 nm and about 7 nm. Additional etch processes may be performed to remove excess oxidation material from sidewalls of the plurality of first conductive layers  401 . 
     With reference to  FIGS.  1  and  9   , at step S 19 , a first palm portion  211  may be formed in the second recess R 2 . 
     With reference to  FIG.  9   , the first palm portion  211  may be formed to fill the second recess R 2  and electrically connect to the plurality of second conductive layers  403  and the bottom conductive layer  105 . In some embodiments, the first palm portion  211  may be formed on the impurity region  103  and electrically connected to the impurity region  103 . In some embodiments, the first palm portion  211  may be formed of a same material as the plurality of second conductive layers  403  or the plurality of first conductive layers  401 . In some embodiments, the first palm portion  211  may be formed of a different material from the plurality of second conductive layers  403  or the plurality of first conductive layers  401 . 
     In some embodiments, the first palm portion  211  may be formed of, for example, tungsten, cobalt, zirconium, tantalum, titanium, aluminum, ruthenium, copper, metal carbides (e.g., tantalum carbide, titanium carbide, tantalum magnesium carbide), metal nitrides (e.g., titanium nitride), transition metal aluminides, or a combination thereof. In some embodiments, the first palm portion  211  may be formed by, for example, chemical vapor deposition, plasma-enhanced chemical vapor deposition, sputtering, or other suitable deposition techniques. 
     In some embodiments, the first palm portion  211  may be formed for example, a group IV material, such as Si, Ge, SiGe, SiGeSn, or the like, or a group III-group V compound material, such as GaAs, GaP, GaAsP, AlInAs, AlGaAs, GaInAs, InAs, GaInP, InP, InSb, GaInAsP, or the like. The first palm portion  211  may be formed by rapid thermal chemical vapor deposition, metal-organic chemical vapor deposition, molecular beam epitaxy, liquid phase epitaxy, vapor phase epitaxy, ultra-high-vacuum chemical vapor deposition, low-pressure chemical vapor deposition, limited reaction processing chemical vapor deposition, or the like. The first palm portion  211  may be doped by n-type dopants or p-type dopants. 
     With reference to  FIG.  9   , a planarization process, such as chemical mechanical polishing, may be performed to remove excess material and provide a substantially flat surface for subsequent processing steps. 
     With reference to  FIGS.  1 ,  10 , and  11   , at step S 21 , the stack may be patterned to form a third recess R 3 , the plurality of first conductive layers  401  may be turned into a plurality of second finger portions  223 ,  225 , the plurality of second conductive layers  403  may be turned into a plurality of first finger portions  213 ,  215 , and the plurality of insulation layers  405  may be turned into the plurality of capacitor insulation layers  231 ,  233 ,  235 . 
     With reference to  FIG.  10   , a second mask layer  411  may be formed on the topmost layer of the stack and may cover the first palm portion  211 . The second mask layer  411  may be line in a top-view perspective (not shown). The second mask layer  411  may be, for example, a hard mask layer formed of a material having etching selectivity to the first conductive layer  401 , the second conductive layer  403 , the insulation layer  405 , the stop layer  107 , and the bottom conductive layer  105 . In some embodiments, the second mask layer  411  may be formed of, for example, amorphous carbon, silicon borocarbonitride, silicon oxycarbonitride, or silicon oxycarbide. 
     With reference to  FIG.  11   , an etch process may be performed to the intermediate semiconductor device illustrated in  FIG.  10    to form the third recess R 3 . The etch process may be, for example, a reactive ion etch, a neutral beam etch, the like, or a combination thereof. The etch process may be anisotropic. The third recess R 3  may be opposite to the first palm portion  211  with the stack interposed therebetween. After the etch process, the sidewalls of the plurality of first conductive layers  401  and the plurality of second conductive layers  403  may be exposed through the third recess R 3 . In some embodiments, the etch process may be a timed isotropic wet etch process. In some embodiments, the etch process may be a selective dry etch process. In some embodiments, the etch process may be a combination of dry and wet etch processes. 
     In some embodiments, the etch rate of the second conductive layer  403  may be faster than the etch rate of the first conductive layer  401  during the etch process. After the etch process, a plurality of recesses maybe formed adjacent to the plurality of second conductive layers  403  and may be regarded as a plurality of dimples  243 D. This plurality of dimples  243 D may be the result of the plurality of second conductive layers  403  being etched laterally during the etch process. 
     After the etch process, the plurality of first conductive layers  401  may be turned into a plurality of second finger portions  223 ,  225 . The plurality of second conductive layers  403  may be turned into a plurality of first finger portions  213 ,  215 . The plurality of insulation layers  405  may be turned into the plurality of capacitor insulation layers  231 ,  233 ,  235 . 
     In some embodiments, the width W 2  of the plurality of capacitor insulation layers  231 ,  233 ,  235  may be greater than the width W 3  of the plurality of first finger portions  213 ,  215  or the width W 4  of the plurality of second finger portions  223 ,  225 . In some embodiments, the width W 3  of the plurality of first finger portions  213 ,  215  may be greater than or equal to the width W 4  of the plurality of second finger portions  223 ,  225 . In some embodiments, the width W 3  of the plurality of first finger portions  213 ,  215  may be less than the width W 4  of the plurality of second finger portions  223 ,  225 . In some embodiments, the width W 3  of the plurality of first finger portions  213 ,  215  may be equal to the width W 5  of the bottom conductive layer  105  but is not limited thereto. In some embodiments, the width W 2  of the plurality of capacitor insulation layers  231 ,  233 ,  235  may be equal to the width W 6  of the stop layer  107  but is not limited thereto. 
     With reference to  FIGS.  1 ,  12 , and  13   , at step S 23 , a plurality of second spacers  243  may be formed to cover the sidewalls of the plurality of first finger portions  213 ,  215  and a third spacer  245  may be formed to cover the sidewall of the bottom conductive layer  105 . 
     With reference to  FIG.  12   , a layer of second dielectric material  413  may be conformally formed to the intermediate semiconductor device illustrated in  FIG.  11   . The layer of second dielectric material  413  may completely fill the plurality of dimples  243 D. In some embodiments, the second dielectric material  413  may be the same as the material of the stop layer  107 , the first dielectric material  409 , or the material of the insulation layer  405 , but is not limited thereto. In some embodiments, the second dielectric material  413  may be for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like. In some embodiments, the second dielectric material  413  may be formed of, for example, a low-k material. In some embodiments, the second dielectric material  413  may be formed of, for example, oxides, nitrides, oxynitrides, silicates (e.g., metal silicates), aluminates, titanates, nitrides, high-k materials, or any combination thereof. The layer of second dielectric material  413  may be formed by, for example, atomic layer deposition, chemical vapor deposition, plasma-enhanced chemical vapor deposition. 
     With reference to  FIG.  13   , an etch process, such as an anisotropic dry etch process, may be performed to remove portions of the layer of second dielectric material  413 . After the etch process, the second dielectric material  413  outside the plurality of dimples  243 D may be removed. The second dielectric material  413  remained in the plurality of dimples  243 D may be regarded as the plurality of second spacers  243  and the third spacer  245 . The third recess R 3  may be turned into the fourth recess R 4 . The plurality of second spacers  243  and the third spacer  245  may be opposite to the first palm portion  211 . The sidewalls of the plurality of second finger portions  223 ,  225  may be exposed through the fourth recess R 4 . In contrast, the sidewalls of the plurality of first finger portions  213 ,  215  may be covered by the plurality of second spacers  243  and the sidewall of the bottom conductive layer  105  may be covered by the third spacer  245 . After the etch process, the second mask layer  411  may be removed. 
     In some embodiments, before the etch process, the second dielectric material  413  deposited outside the plurality of dimples  243 D may be transformed into a transformed dielectric material (not shown). In an embodiment, transformed dielectric material may have a different etch selectivity than the second dielectric material  413 . By altering the etch selectivity of the transformed dielectric material as compared to the second dielectric material  413 , the etch process to remove excess second dielectric material  413  from outside the plurality of dimples  243 D may be more easily controlled. In such situation, the etch process may be an isotropic etch process. Transformation may occur by plasma treatment, implantation, oxidation, or a combination thereof. The transformation process is sufficient to alter the etch selectivity of the second dielectric material  413  outside of the plurality of dimples  243 D, but does not affect mobility or degrade performance of the plurality of first finger portions  213 ,  215  and the plurality of second finger portions  223 ,  225 . 
     In some embodiments, the layer of second dielectric material  413  may not be laterally etched during the etch process. In other words, the sidewall of the stack may be substantially vertical. Alternatively, a selective oxidation process may be performed to selectively form the plurality of second spacers  243  on the sidewalls of the plurality of first finger portions  213 ,  215  and the third spacer  245  on the sidewall of the bottom conductive layer  105 . The selective oxidation process may be a selective wet oxidation or selective dry oxidation. If a selective wet oxidation process is desired, a high-pressure steam oxidation process may be performed. The high-pressure steam oxidation may include performing the oxidation above an atmospheric pressure in a combined H 2 O/N-based environment at relatively low temperatures ranging, for example, from about 500° C. to about 700° C. If a selective dry oxidation process is desired, a oxidation may be performed at atmospheric pressure, e.g., approximately 10,1325 pascals (Pa) (e.g., in an O 2  or O 2 /N 2  based environment at temperatures ranging, for example, from about 600° C. to about 800° C. The selective oxidation process may be time-based such that the plurality of second spacers  243  or the third spacer  245  having a desired width may be achieved. Additional etch processes may be performed to remove excess oxidation material from sidewalls of the plurality of first finger portions  213 ,  215 . 
     In some embodiments, the width W 7  of the plurality of second spacers  243  may be larger than or equal to the width W 1  of the plurality of first spacers  241 . In some embodiments, the width W 7  of the plurality of second spacers  243  may be less than the width W 1  of the plurality of first spacers  241 . In some embodiments, the width W 7  of the plurality of second spacers  243  may be between about 5 nm and about 7 nm. 
     With reference to  FIGS.  1  and  14   , at step S 25 , a second palm portion  221  may be formed in the fourth recess R 4 . 
     With reference to  FIG.  14   , the second palm portion  221  may be formed to fill the fourth recess R 4  and electrically connect to the plurality of second finger portions  223 ,  225 . The second palm portion  221  may be electrically insulated from the plurality of first finger portions  213 ,  215  and the bottom conductive layer  105  by the plurality of second spacers  243  and the third spacer  245 . In some embodiments, the second palm portion  221  may be formed of a same material as the plurality of second finger portions  223 ,  225  or the plurality of first finger portions  213 ,  215 . In some embodiments, the second palm portion  221  may be formed of a different material from the plurality of second finger portions  223 ,  225  or the plurality of first finger portions  213 ,  215 . In some embodiments, the second palm portion  221  may be formed of a same material as the first palm portion  211  but is not limited thereto. In some embodiments, the second palm portion  221  and the first palm portion  211  may have a same electrical type such as n-type or p-type. 
     In some embodiments, the second palm portion  221  may be formed of, for example, tungsten, cobalt, zirconium, tantalum, titanium, aluminum, ruthenium, copper, metal carbides (e.g., tantalum carbide, titanium carbide, tantalum magnesium carbide), metal nitrides (e.g., titanium nitride), transition metal aluminides, or a combination thereof. In some embodiments, the second palm portion  221  may be formed by, for example, chemical vapor deposition, plasma-enhanced chemical vapor deposition, sputtering, or other suitable deposition techniques. 
     In some embodiments, the second palm portion  221  may be formed for example, a group IV material, such as Si, Ge, SiGe, SiGeSn, or the like, or a group III-group V compound material, such as GaAs, GaP, GaAsP, AlInAs, AlGaAs, GaInAs, InAs, GaInP, InP, InSb, GaInAsP, or the like. The second palm portion  221  may be formed by rapid thermal chemical vapor deposition, metal-organic chemical vapor deposition, molecular beam epitaxy, liquid phase epitaxy, vapor phase epitaxy, ultra-high-vacuum chemical vapor deposition, low-pressure chemical vapor deposition, limited reaction processing chemical vapor deposition, or the like. The second palm portion  221  may be doped by n-type dopants or p-type dopants. 
     With reference to  FIG.  14   , a planarization process, such as chemical mechanical polishing, may be performed to remove excess material and provide a substantially flat surface for subsequent processing steps. 
     With reference to  FIG.  14   , the first palm portion  211  and the plurality of first finger portions  213 ,  215  together configure a bottom electrode. The second palm portion  221  and the plurality of second finger portions  223 ,  225  together configure a top electrode. The plurality of capacitor insulation layers  231 ,  233 ,  235 , the plurality of first spacers  241 , the plurality of second spacers  243 , and the third spacer  245  may electrically insulate the bottom electrode and the top electrode. The top electrode, the bottom electrode, and the plurality of capacitor insulation layers  231 ,  233 ,  235  together configure a capacitor structure. In some embodiments, the bottom electrode may further include the bottom conductive layer  105 . The bottom conductive layer  105  may be electrically insulated from the second finger portion  223  by the stop layer  107 . 
       FIGS.  15  to  18    illustrate, in schematic cross-sectional view diagrams, semiconductor devices  1 B,  1 C,  1 D, and  1 E in accordance with some embodiments of the present disclosure. 
     With reference to  FIG.  15   , the semiconductor device  1 B may have a structure similar to that illustrated in  FIG.  14   . The same or similar elements in  FIG.  15    as in  FIG.  14    have been marked with similar reference numbers and duplicative descriptions have been omitted. In the semiconductor device  1 B, the impurity region  103  may be disposed under the second palm portion  221  and contacting the second palm portion  221 . 
     With reference to  FIG.  16   , the semiconductor device  1 C may have a structure similar to that illustrated in  FIG.  14   . The same or similar elements in  FIG.  16    as in  FIG.  14    have been marked with similar reference numbers and duplicative descriptions have been omitted. In the semiconductor device  1 C, the third spacer  245  may be disposed between the bottom conductive layer  105  and the first palm portion  211  to electrically insulate the bottom conductive layer  105  and the first palm portion  211 . The second palm portion  221  may be contacting the bottom conductive layer  105  and electrically connected to the bottom conductive layer  105 . 
     With reference to  FIG.  17   , the semiconductor device  1 D may have a structure similar to that illustrated in  FIG.  16   . The same or similar elements in  FIG.  17    as in  FIG.  16    have been marked with similar reference numbers and duplicative descriptions have been omitted. In the semiconductor device  1 D, the impurity region  103  may be disposed under the second palm portion  221  and contacting the second palm portion  221 . 
     With reference to  FIG.  18   , the semiconductor device  1 E may have a structure similar to that illustrated in  FIG.  14   . The same or similar elements in  FIG.  18    as in  FIG.  14    have been marked with similar reference numbers and duplicative descriptions have been omitted. The semiconductor device  1 E may include a buried insulation layer  111 . The buried insulation layer  111  may be horizontally disposed in the substrate  101 . The impurity region  103  may be disposed above the buried insulation layer  111 . The buried insulation layer  111  may reduce the current leakage. 
       FIGS.  19  to  22    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating a semiconductor device IF in accordance with another embodiment of the present disclosure. 
     With reference to  FIG.  19   , an intermediate semiconductor device may be fabricated with a procedure similar to that illustrated in  FIGS.  2  to  6   . In contrast to  FIG.  6   , the stack may have a substantially vertical sidewall after the etch process. In the present embodiment, the first conductive layer  401  is a layer of Si 0.50 Ge 0.50  and second conductive layer  403  is a layer of Si. 
     With reference to  FIG.  20   , a low-temperature oxidation process may be conducted at a process temperature less than 700° C. to oxidize the exposed sidewalls of the plurality of first conductive layers  401  and the second conductive layer  403 . In the present embodiment, a wet oxidation conducted at 630° C. is employed. The plurality of first conductive layers  401  formed of Si 0.50 Ge 0.50  may oxidize at least ten times faster than the plurality of second conductive layers  403  formed of Si under such condition. As a result, the sacrificial layers  415  formed during the low-temperature oxidation process may be relatively thicker than the sacrificial layers  417  formed during the low-temperature oxidation process. 
     With reference to  FIG.  21   , an oxide etch process may be performed to remove the sacrificial layers  417 . The oxide etch process may be a plasma-assisted dry etch process that involves simultaneous exposure of a substrate to hydrogen, NF 3  and NH 3  plasma by-products or a wet etch using a solution containing hydrofluoric acid. The exposed plurality of second conductive layers  403  may be served as seed to epitaxially grow first palm portion  211 . It should be noted that and portions of the sacrificial layers  415  may also be removed. However, due to the sacrificial layers  415  are thicker than the sacrificial layers  417 , the sacrificial layers  415  may still cover the plurality of first conductive layers  401  after the removal of the sacrificial layers  417 . The remained sacrificial layers  415  may be referred to as the plurality of first spacers  241 . 
     With reference to  FIG.  22   , the other elements (e.g., the first palm portion  211  and the second palm portion  221 ) may be formed with a procedure similar to that illustrated in  FIGS.  9  to  14   . 
       FIGS.  23  to  27    illustrate, in schematic cross-sectional view diagrams, a flow for fabricating a semiconductor device  1 G in accordance with another embodiment of the present disclosure. 
     With reference to  FIG.  23   , an inter-dielectric layer  109  may be blanket deposited on the substrate  101 . The bottom conductive layer  105  may be formed in the bottom conductive layer  105  by, for example, a damascene process or other suitable process. The stop layer  107  may be optionally deposited on the inter-dielectric layer  109 . The plurality of first conductive layers  401 , the plurality of insulation layers  405 , and the plurality of second conductive layers  403  may be sequentially and alternatively formed on the stop layer  107 . 
     With reference to  FIG.  24   , the first recess R 1  and the plurality of dimples  241 D may be formed with a procedure similar to that illustrated in  FIGS.  5  and  6   . It should be noted that the inter-dielectric layer  109  may be intact after the etch process. 
     With reference to  FIG.  25   , the first spacers  241  and the first palm portion  211  may be formed with a procedure similar to that illustrated in  FIGS.  7  to  9   . The first palm portion  211  may be formed on the inter-dielectric layer  109  and may contact the bottom conductive layer  105 . That is, the first palm portion  211  may be electrically coupled to the impurity region  103  through the bottom conductive layer  105 . 
     With reference to  FIG.  26   , the fourth recess R 4  and the plurality of dimples  243 D may be formed with a procedure similar to that illustrated in  FIGS.  10  and  11   . It should be noted that the inter-dielectric layer  109  may be intact after the etch process. 
     With reference to  FIG.  27   , the second spacers  243  and the second palm portion  221  may be formed with a procedure similar to that illustrated in  FIGS.  12  to  14   . 
       FIG.  28    illustrates, in a schematic cross-sectional view diagram, a semiconductor device  1 H in accordance with another embodiment of the present disclosure. 
     With reference to  FIG.  28   , the semiconductor device  1 H may have a structure similar to that illustrated in  FIG.  27   . The same or similar elements in  FIG.  28    as in  FIG.  27    have been marked with similar reference numbers and duplicative descriptions have been omitted. In the semiconductor device  1 H, the impurity region  103  may be disposed under the second palm portion  221 . The second palm portion  221  and the impurity region  103  may be electrically coupled through the bottom conductive layer  105  interposed therebetween. 
     One aspect of the present disclosure provides a semiconductor device including a first palm portion positioned above a substrate; a second palm portion positioned above the substrate and opposite to the first palm portion; a first finger portion arranged substantially in parallel with a main surface of the substrate, positioned between the first palm portion and the second palm portion, and connecting to the first palm portion; a second finger portion arranged substantially in parallel with the first finger portion, positioned between the first palm portion and the second palm portion, and connecting to the second palm portion; a capacitor insulation layer positioned between the first finger portion and the second finger portion; a first spacer positioned between the first palm portion and second finger portion; and a second spacer positioned between the second palm portion and the first finger portion. 
     Another aspect of the present disclosure provides a method for fabricating a semiconductor device including providing a substrate; sequentially forming a first conductive layer, an insulation layer, and a second conductive layer over the substrate to configure a stack; patterning the stack to form a first recess and expose an impurity region in the substrate; forming a first spacer to cover a sidewall of the first conductive layer; forming a first palm portion in the first recess and connecting to the second conductive layer; patterning the stack to form a third recess, turn the second conductive layer into a first finger portion, and turn the first conductive layer into a second finger portion, wherein the third recess is opposite to the first palm portion; forming a second spacer to cover a sidewall of the first finger portion, wherein the second spacer is opposite to the first palm portion; and forming a second palm portion in the third recess and connecting to the second finger portion. 
     Due to the design of the semiconductor device of the present disclosure, the contact area of the capacitor structure may be increased. As a result, the performance of the semiconductor device  1 A may be improved. In addition, the process flow may be easily integrated with fin type transistors. 
     Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. For example, many of the processes discussed above can be implemented in different methodologies and replaced by other processes, or a combination thereof. 
     Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, and steps.