Capacitor and method of forming the same

Abstract

A capacitor includes a plurality of cup-shaped lower electrodes on a substrate, a compliant capacitor dielectric layer conforming to inner and outer surfaces of the cup-shaped lower electrodes, an upper electrode covering surfaces of the capacitor dielectric layer, and a support layer between outer surfaces of the cup-shaped lower electrodes to connect the cup-shaped lower electrodes. The capacitor further includes an annealed oxide layer sandwiched between the inner surfaces of the cup-shaped lower electrodes and the capacitor dielectric layer, and sandwiched between the outer surfaces of the cup-shaped lower electrodes and the capacitor dielectric layer. The support layer is between the outer surfaces of the cup-shaped lower electrodes to connect the cup-shaped lower electrodes. The support layer includes an upper support layer, a middle support layer, and a lower support layer to connect upper, middle, and lower portions of the outer surfaces of the cup-shaped lower electrodes, respectively. A method of forming the capacitor is also provided.

Description

TECHNICAL FIELD

[0001] The present invention relates to a capacitor, and more particularly to a capacitor for dynamic random access memory and a method of forming the same. BACKGROUND

[0002] Dynamic random access memory (DRAM) devices are widely used in consumer electronic products. In order to increase the element density and improve the overall performance of DRAM devices, the manufacturing technology of DRAM devices continues to strive towards miniaturization of element size.

[0003] However, as the element size continues to shrink, many challenges arise. For example, in the process of forming a capacitor, the lower electrode is easily affected by etching, resulting in a decrease in the capacitance value. Therefore, there is still a need to improve the method of forming a capacitor in a DRAM device to overcome the problem of damage to the lower electrode due to the process. SUMMARY

[0004] The present invention provides a capacitor comprising a plurality of cup-shaped lower electrodes on a substrate, a capacitor dielectric layer conforming to the inner and outer surfaces of the cup-shaped lower electrodes, an upper electrode covering the surface of the capacitor dielectric layer, and a support layer between the outer surfaces of the cup-shaped lower electrodes to connect the cup-shaped lower electrodes. The capacitor further comprises an annealed oxide layer sandwiched between the inner surfaces of the cup-shaped lower electrodes and the capacitor dielectric layer, and between the partial outer surfaces of the cup-shaped lower electrodes and the capacitor dielectric layer. The support layer is located between the outer surfaces of the cup-shaped lower electrodes to connect the cup-shaped lower electrodes. The support layer includes an upper support layer, a middle support layer, and a lower support layer, which respectively connect the upper, middle, and lower portions of the outer surfaces of the cup-shaped lower electrodes.

[0005] A method for forming a capacitor includes providing a substrate; sequentially forming a template layer and a support layer on the substrate; forming a plurality of cup-shaped openings in the template layer and the support layer; forming a lower electrode material layer in the cup-shaped openings and on a top surface of the support layer; removing the lower electrode material layer on the top surface of the support layer, leaving the remaining lower electrode material layer as a plurality of cup-shaped lower electrodes; removing an upper portion of the support layer such that sidewalls of any two of the cup-shaped lower electrodes protrude above the top surface of the support layer; forming an oxide layer on surfaces of the cup-shaped lower electrodes and on a surface of the support layer; forming an annealed oxide layer; forming a protective layer on the annealed oxide layer, wherein the protective layer closes top ends of the cup-shaped openings; forming a mask on a top surface of a portion of the cup-shaped lower electrodes; removing the protective layer and the support layer except under the mask; removing the remaining protective layer, the template layer, and a portion of the annealed oxide layer such that the remaining annealed oxide layer is attached to inner side surfaces of the cup-shaped lower electrodes; forming a capacitor dielectric layer on surfaces of the cup-shaped lower electrodes, surfaces of the remaining annealed oxide layer, and a surface of the support layer; and forming an upper electrode on surfaces of the capacitor dielectric layer. BRIEF DESCRIPTION OF DRAWINGS

[0006] So that the features and advantages of the present application can be understood in more detail, different embodiments of the present application will now be described in detail with reference to the following drawings:

[0007] Figure 1 , Figure 2 , Figure 4 , Figure 6 , Figure 8 , Figure 10 , Figure 12 , Figure 14 , Figure 16 , Figure 18 and Figure 21 are cross-sectional views illustrating different stages of forming a capacitor according to some embodiments of the present application.

[0008] Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 , Figure 13 , Figure 15 , Figure 17 and Figure 19 are top views of the capacitor corresponding to the cross-sectional views shown in Figure 2 , Figure 4 , Figure 6 , Figure 8 , Figure 10 , Figure 12 , Figure 14 , Figure 16 and Figure 18 , where the cross-sectional lines between the arrows in the top views can correspond to the cross-sectional views.

[0009] Figure 20 is shown in accordance with some embodiments of the present application, illustrating portions of elements of a capacitor corresponding to Figure 18 is shown in accordance with some embodiments of the present application, illustrating portions of elements of a capacitor corresponding to

[0010] Reference Signs:

[0011] 100: substrate

[0012] 102: base material

[0013] 102a: isolation structure

[0014] 104: cap layer

[0015] 106: dielectric layer

[0016] 120: bit line

[0017] 122, 124: conductive layer

[0018] 126: dielectric layer

[0019] 130: capacitor contact

[0020] 132, 136: conductive layer

[0021] 134: silicide layer

[0022] 200: support layer

[0023] 210, 210’: lower support layer

[0024] 210a: contact pad

[0025] 220, 220’: middle support layer

[0026] 230, 230’, 230”: upper support layer

[0027] 300: template layer

[0028] 310, 310’: lower template layer

[0029] 320, 320’: upper template layer

[0030] 400: mask

[0031] 500: lower electrode material layer

[0032] 500’, 500”: (cup-shaped) lower electrode

[0033] 600, 600’, 600”: annealed oxide layer

[0034] 700: protective layer

[0035] 710, 710', 720, 720': protective layer

[0036] 730: antireflection layer

[0037] 800: mask

[0038] 900: capacitor dielectric layer

[0039] 1000: upper electrode

[0040] D: distance

[0041] O: cup-shaped opening

[0042] T N : thickness

[0043] W U : upper width

[0044] W L : lower width DETAILED DESCRIPTION

[0045] Embodiments of the present application provide a protective layer to protect the lower electrode during the formation of the capacitor. By covering part of the surface of the lower electrode with the annealed oxide layer, the work function can be reduced and the leakage current of the high-k dielectric can be suppressed. Furthermore, by forming the plurality of cup-shaped lower electrodes and the annealed oxide layer before forming the protective layer, the risk of significantly reducing the height of the cup-shaped lower electrode when removing the template layer can be reduced. Moreover, by removing the upper support layer and the middle support layer in the same step when removing the template layer, the complexity of the process can be reduced.

[0046] Figure 1 FIG. 1 is a cross-sectional view illustrating the formation of a capacitor according to some embodiments of the present application.

[0047] First, a substrate 100 is provided. In Figure 1 the substrate 100 includes a base material 102, a cap layer 104, and a dielectric layer 106.

[0048] The base material 102 includes an isolation structure 102a disposed therein to define an active region. Word lines (not shown) are further embedded in the base material 102, which serve as gates and include a gate dielectric layer, a gate liner, and a gate electrode (not shown).

[0049] The cap layer 104 is disposed on the base material 102. The cap layer 104 can include silicon oxide (e.g., thermal silicon oxide, tetraethylorthosilicate (TEOS) oxide), silicon nitride (SiN), silicon oxynitride (SiON), or a combination thereof.

[0050] A dielectric layer 106 is disposed on the capping layer 104. The dielectric layer 106 may comprise silicon nitride, silicon oxynitride, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), spin-on glass (SOG), undoped silicon glass (USG), tetraethylorthosilicate (TEOS) oxide, low dielectric constant dielectric materials, and / or other suitable dielectric materials, etc.

[0051] The substrate 100 further includes bit lines 120 and capacitor contacts 130 disposed in the dielectric layer 106. Bit lines 120 include conductive layers 122, 124, and a dielectric layer 126. Conductive layers 122 and 124 may be conductive materials, including doped polysilicon, metals, or metal nitrides, such as tungsten (W), titanium (Ti), and titanium nitride (TiN). The dielectric layer 126 may be a dielectric material, including nitrides or oxides, such as silicon nitride or silicon oxide.

[0052] The capacitor contact 130 includes a conductive layer 132, a silicide layer 134, and a conductive layer 136. The material of the conductive layer 132 is similar to that of the conductive layers 122 and 124. The silicide layer 134 may be a metal silicide layer, such as cobalt silicide.

[0053] like Figure 1 As shown, a support layer 200 and a template layer 300 are sequentially formed on the substrate 100. Figure 1 In this embodiment, the support layer 200 and the template layer 300 are alternately arranged vertically. Specifically, a lower support layer 210, a lower template layer 310, a middle support layer 220, an upper template layer 320, and an upper support layer 230 are formed sequentially. The support layer 200 is used to connect to the subsequently formed cup-shaped lower electrode.

[0054] The lower support layer 210 includes contact pads 210a for subsequent electrical connection between the capacitor contact 130 and the cup-shaped lower electrode (not shown). The contact pads 210a contain a conductive material, similar to the conductive layer 136 described above, and will not be described again here.

[0055] The support layer 200 and the template layer 300 are made of etching-selective materials. The material of the support layer 200 may be a nitride, such as silicon nitride, silicon oxynitride, silicon carbonitride, silicon carbide, or a combination thereof. The material of the template layer 300 may be an oxide, such as silicon oxide, borosilicate glass, or a combination thereof.

[0056] like Figure 2 As shown, a mask 400 is formed on the upper support layer 230. See also...Figure 3 The mask 400 is patterned to form an array of openings that expose the upper support layer 230 below. The cup-shaped opening (not shown) that forms the cup-shaped lower electrode will be defined by the mask 400.

[0057] Mask 400 may be a photoresist layer. Mask 400 may be a hard protective layer containing oxides, oxynitrides, or other suitable dielectric materials.

[0058] Next, as Figure 4 As shown, multiple cup-shaped openings O are formed in the template layer 300 and the support layer 200. The cup-shaped openings O penetrate the upper support layer 230, the upper template layer 320, the middle support layer 220, and the lower template layer 310, exposing the contact pad 210a in the lower support layer 210. The cup-shaped openings O do not penetrate the lower support layer 210. Here, the support layer 200 and the template layer 300 with cup-shaped openings O are represented by the upper, middle, and lower support layers 230', 220', and 210', and the upper and lower template layers 320', 310', respectively.

[0059] Can be used as a reference Figure 5 The cup-shaped openings O can be arranged in an array. Figure 5 In one embodiment, a contact pad 210a, a lower support layer 210, and a shield 400 are sequentially arranged extending radially from the center of the cup-shaped opening O.

[0060] The aspect ratio of the cup-shaped opening O is greater than 10 and less than 100. Within this range, the contact area between the subsequent cup-shaped lower electrode and the capacitor dielectric layer can be increased without the lower electrode shifting or tilting.

[0061] The formation of the cup-shaped opening O involves using a mask 400 as an etching mask to etch the support layer 200 and the template layer 300, excluding those covered by the mask 400, using an etching process. Next, as... Figure 6 As shown, remove the mask 400.

[0062] Can be used as a reference Figure 7 Extending radially from the center of the cup-shaped opening O, a contact pad 210a, a lower support layer 210, and an upper support layer 230' are sequentially provided.

[0063] Next, as Figure 8 As shown, a lower electrode material layer 500 is formed in the cup-shaped opening O and on the top surface of the support layer 200. Specifically, the lower electrode material layer 500 is compliantly formed on the top surface of the lower support layer 200 (including the contact pad 210a), the side surface of the lower template layer 310', the side surface of the middle support layer 220', the side surface of the upper template layer 320', the side surface of the upper support layer 230', and the top surface.

[0064] Can be used as a referenceFigure 9 The lower electrode material layer 500 covers the surface of the cup-shaped openings O, thus the cup-shaped openings O under the lower electrode material layer 500 are represented by dotted lines.

[0065] The material of the lower electrode material layer 500 can be metal, metal nitride or metal silicide, such as titanium nitride, tantalum nitride, tungsten, titanium tungsten, aluminum, copper, titanium, etc.

[0066] Next, as shown in FIG. 5, the lower electrode material layer 500 on the top surface of the support layer 200 is removed, leaving the remaining lower electrode material layer as a plurality of cup-shaped lower electrodes 500'. Figure 10 The removal of the lower electrode material layer 500 and the upper portion of the support layer 200 is performed simultaneously by dry etching. The dry etching has a selectivity ratio (etching rate ratio) of the cup-shaped lower electrodes 500' to the support layer 200 of about 10:1-30:1. By the above etching selectivity ratio, the top surface of the lower electrode material layer can be cut off.

[0067] The removal of the upper portion of the support layer 200 includes removing the upper portion of the upper support layer 230' to reduce the height of the upper support layer 230' so that the subsequently formed annealed oxide layer can be retained on the outer side surface of the cup-shaped lower electrodes to facilitate maintaining the height of the cup-shaped lower electrodes. Here, the reduced height of the upper support layer 230' is denoted as 230".

[0068] The lower support layer 210' continuously extends to the bottom of each cup-shaped lower electrode 500', the middle support layer 220' connects the middle of the outer side surface of each cup-shaped lower electrode 500', and the upper support layer 210' connects the upper portion of the outer side surface of each cup-shaped lower electrode 500'.

[0069] Referring to FIG. 6, each cup-shaped opening O is surrounded by one cup-shaped lower electrode 500', and each cup-shaped lower electrode is surrounded by the upper support layer 230". It should be noted that the lower electrode material layer 500 still covers the surface of the cup-shaped openings O, thus the cup-shaped openings O under the lower electrode material layer 500 are represented by dotted lines.

[0070] Figure 11 Next, as shown in FIG. 7, an oxide layer is formed on the surface of each cup-shaped lower electrode 500' and on the surface of the support layer 200. The oxide layer includes metal oxide, such as aluminum oxide. Then, the oxide layer is annealed to form an annealed oxide layer 600.

[0071] Next, as shown in FIG. 7, an oxide layer is formed on the surface of each cup-shaped lower electrode 500' and on the surface of the support layer 200. The oxide layer includes metal oxide, such as aluminum oxide. Then, the oxide layer is annealed to form an annealed oxide layer 600. Figure 12

[0072] ​​The annealing oxide layer 600 is formed on the inner and outer surfaces of the cup-shaped lower electrode 500' by an annealing process to reduce the work function and suppress leakage current of high dielectric constant dielectric. The annealing oxide layer 600 can further protect the cup-shaped lower electrode 500' from subsequent processes, reduce the height of the cup-shaped lower electrode 500', and the like.

[0073] The cup-shaped lower electrode 500' comprises a metal, such as titanium and titanium nitride. The annealing process can cause the annealing oxide layer 600 to comprise the same metal element or / and the same metal oxide as the cup-shaped lower electrode 500' to improve the resistance and the capacitance. The annealing oxide layer 600 comprises TiAl, TiAlO, TiO x , Al2O3, and the like.

[0074] Referring back to Figure 13 , the annealing oxide layer 600 covers the surface of the cup-shaped opening, and thus the cup-shaped opening O under the annealing oxide layer 600 is represented by a dashed line.

[0075] Next, as shown in Figure 14 , a protective layer 700 is formed on the annealing oxide layer 600, wherein the protective layer 700 closes the top end of the cup-shaped opening O. Then, a mask 800 is formed on the top surface of a portion of the cup-shaped lower electrode 500'.

[0076] The protective layer 700 is formed to provide a flat surface for facilitating subsequent pattern definition. The protective layer 700 comprises a first protective layer 710 and a second protective layer 720. The protective layer 700 can comprise only one protective layer.

[0077] In the embodiment of Figure 14 , since the aspect ratio of the cup-shaped opening O is relatively large, and the first protective layer 710 has poor step coverage, the upper sidewall of the cup-shaped opening O is covered by the first protective layer 710, and the top end of the cup-shaped opening is closed by the overhang 710a of the first protective layer 710 without filling the cup-shaped opening O.

[0078] The first protective layer 710 and the second protective layer 720 can comprise oxygen-containing materials or carbon-containing materials, such as silicon oxide or carbon, and the like.

[0079] Next, continuing to refer to Figure 14 , an anti-reflective layer 730 can be further formed on the second protective layer 720 after the formation of the second protective layer 720 to prevent the underlying film layers from reflecting during exposure, which is helpful for pattern transfer.

[0080] Next, continuing to refer to Figure 14 , the mask 800 is formed on the top surface of a portion of the cup-shaped lower electrode 500'. Referring back to Figure 15The mask 800 covers a portion of each cup opening O (corresponding to the cup-shaped lower electrode) and exposes another portion of each cup opening O (corresponding to the cup-shaped lower electrode). Each area not covered by the mask 800 includes more than four cup openings O to facilitate subsequent removal of the template layer 300. The area not covered by the mask 800 can include eight cup openings O. In other embodiments, the area not covered by the mask 800 can include four or six cup openings O (not shown).

[0081] Next, as shown in FIG. 8B, the top surface of the lower electrode material layer 500 is removed. The top surface of the lower electrode material layer 500 can be removed by dry etching using a halocarbon etchant (e.g., CF4, CHF3, CH2F2, etc.). The halocarbon etchant can be used to remove the top surface of the lower electrode material layer 500 without damaging the cup-shaped lower electrode 500’. Figure 16 Then, as shown in FIG. 8C, the protective layer 700 and the support layer 200 not under the mask 800 are removed, and the mask 800 is removed. Specifically, the second protective layer 720 and the first protective layer 710, the upper support layer 230”, the upper template layer 320’, and the middle support layer 220’ outside the mask 800 are removed.

[0082] The removal of the protective layer 700 and the support layer 200 further includes removal of a portion of the annealed oxide layer 600 and a portion of the cup-shaped lower electrode 500’. Specifically, the removal of the portion of the annealed oxide layer 600 includes removal of the annealed oxide layer 600 not covered by the mask 800 and outside the cup-shaped lower electrode 500’. The removal of the portion of the cup-shaped lower electrode 500’ includes thinning of the upper portion of the cup-shaped lower electrode 500’ not covered by the mask 800. Since the cup-shaped opening O has a large aspect ratio, even after the annealed oxide layer 600 not covered by the mask 800 is removed, a portion of the annealed oxide layer 600 remains inside the cup-shaped lower electrode 500’. Here, the remaining annealed oxide layer 600 is denoted as 600’, and the remaining cup-shaped lower electrode 500’ is denoted as 500”.

[0083] The removal of the protective layer 700 and the support layer 200 not under the mask 800 can include dry etching using a halocarbon etchant (e.g., CF4, CHF3, CH2F2, etc.). The ratio of carbon, fluorine, and hydrogen in the halocarbon etchant improves the etching selectivity of the etchant to the cup-shaped lower electrode 500’, so the protective layer 700 and the support layer 200 can be removed while reducing damage to the cup-shaped lower electrode 500’.

[0084] Compared to the case where the top surface of the lower electrode material layer is continuously removed after the mask is formed, by removing the top surface of the lower electrode material layer 500 before the mask 800 is formed, the distance between the top surface of the cup-shaped lower electrode 500” and the upper support layer 230” can be increased, thereby increasing the contact area between the subsequent capacitor dielectric layer 900 and the cup-shaped lower electrode 500”. In addition, the present embodiment can form the annealed oxide layer 600 after removing the top surface of the lower electrode material layer 500, which can protect the cup-shaped lower electrode 500’ from being damaged in subsequent processes.

[0085] In addition, compared to removing the upper support layer and the middle support layer not covered by the mask in two steps, removing the upper support layer 230" and the middle support layer 220' in one step can reduce one cleaning process, achieve process simplification, and reduce the case of damage to the cup-shaped lower electrode 500' in the process.

[0086] Referring to Figure 17 The cup-shaped lower electrode 500" and the annealed oxide layer 600' covered by the second protective layer 720' are indicated by dashed lines. From Figure 17 It can be seen that the cup-shaped lower electrode 500" and the annealed oxide layer 600' surrounding the cup-shaped opening O are partially covered by the second protective layer 720' and partially exposed. In addition, the annealed oxide layer 600' covered by the second protective layer 720' is located on the inner side and the outer side of the cup-shaped lower electrode 500", and the annealed oxide layer 600' not covered by the second protective layer 720' is located on the inner side of the cup-shaped lower electrode 500".

[0087] Then, as Figure 18 shown, the remaining protective layer 700, the template layer 300, and a portion of the annealed oxide layer 600' are removed, so that the remaining annealed oxide layer 600" is attached to the inner side surface of the cup-shaped lower electrode 500". Specifically, the remaining second protective layer 720' and the first protective layer 710', the upper template layer 320, the lower template layer 310, and a portion of the annealed oxide layer 600' are removed. This removal step further includes removing a portion of the upper support layer 230", so that the remaining upper support layer 230" does not contact the annealed oxide layer 600". Here, the remaining upper support layer 230" is denoted as 230"'.

[0088] This removal step reduces the thickness of most of the annealed oxide layer 600', and leaves the surface of the cup-shaped lower electrode 500" formed by the annealing process to have a high dielectric constant TiO x dangling bond.

[0089] The annealed oxide layer 600" is located on the inner side surface of each cup-shaped lower electrode 500". The annealed oxide layer 600" further extends to the top surface and a portion of the outer side surface of the cup-shaped lower electrode 500" having the upper support layer 230"' on the outer side surface, but does not contact the upper support layer 230".

[0090] The ratio of the distance D from the top surface of the cup-shaped lower electrode 500" to the top surface of the upper support layer 230"' to the thickness T N of the upper support layer 230"' is 0.8 or more, so as to increase the coverage area of the capacitive dielectric layer and improve the capacitance value. In some embodiments, the ratio of the distance D to the thickness T N may be, for example, about 1.

[0091] The sidewall of the cup-shaped lower electrode 500" with the outer surface having the upper support layer 230" is higher than the sidewall of the cup-shaped lower electrode 500" with the outer surface not having the upper support layer 230".

[0092] Since the inner surface of the cup-shaped lower electrode 500" is protected by the annealed oxide layer 600", the inner surface of the sidewall of the cup-shaped lower electrode 500" is substantially not affected by the etching, while the annealed oxide layer 600' is affected by the etching and is tapered at its upper portion. On the other hand, the outer surface of the sidewall of the cup-shaped lower electrode 500" is affected by the etching and is also tapered at its upper portion. Specifically, the upper portion of the sidewall of the cup-shaped lower electrode 500" with the outer surface not having the upper support layer 230" has a smaller width (W U <W L ) than the lower portion. In contrast, the sidewall of the cup-shaped lower electrode 500" with the outer surface having the upper support layer 230" has substantially the same width (W U = W L ) at the upper and lower portions. It should be noted that "substantially the same" can include exactly the same, or having a variation of within 10%.

[0093] The ratio of the average width of the annealed oxide layer 600" to the average width of the cup-shaped lower electrode 500" is greater than 0 and less than or equal to 1.7. Thereby, the capacitance value can be further improved with reduced leakage current. The average width of the annealed oxide layer 600" is about 0.1 to 0.5 times the average width of the cup-shaped lower electrode 500".

[0094] The support layers 200 are located between the outer surfaces of the cup-shaped lower electrodes 500" to connect the cup-shaped lower electrodes. The upper support layer 230"', the middle support layer 220', and the lower support layer 210' connect the upper, middle, and lower portions of the outer surfaces of the cup-shaped lower electrodes, respectively, to strengthen the mechanical strength of the capacitor and avoid the phenomenon of deformation or even tilting of the capacitor.

[0095] Reference can be made to Figure 19 and Figure 20 , Figure 19 The relative positions of the cup-shaped lower electrode 500" and the annealed oxide layer 600" in the top view are shown, while Figure 20 The relative positions of the cup-shaped lower electrode 500" in the top view are shown only. Specifically, in Figure 20 each cup-shaped opening O is surrounded by a cup-shaped lower electrode 500". In addition, the positions covered by the original mask 800 (see Figure 15 ), the upper support layer 230" is exposed in the top view at this stage, while the positions not covered by the original mask 800 (see Figure 15 ), the lower support layer 210' is exposed in the top view at this stage.

[0096] Reference can be made to Figure 19, at locations not covered by the original mask 800 (see Figure 15 ) the annealed oxide layer 600" is only on the inner side of the cupped lower electrode 500"; while at locations covered by the original mask 800 (see Figure 15 ) the annealed oxide layer 600" is on the inner side, the outer side, and the top of the cupped lower electrode 500". That is, in Figure 19 , the annealed oxide layer 600" completely covers the inner side of each cupped lower electrode 500" but only partially covers the top and the outer side of each cupped lower electrode 500".

[0097] Next, as shown in Figure 21 , a capacitor dielectric layer 900 is formed on the surface of the cupped lower electrode 500", the surface of the remaining annealed oxide layer 600", and the surface of the support layer 200.

[0098] The capacitor dielectric layer 900 conformally covers the inner and outer surfaces of the cupped lower electrode 500". The annealed oxide layer 600" is sandwiched between the capacitor dielectric layer 900 and the inner surface of the cupped lower electrode 500" and between the capacitor dielectric layer 900 and the partial outer surface of the cupped lower electrode 500", thereby suppressing the generation of leakage current. The annealed oxide layer 600" is also sandwiched between the capacitor dielectric layer 900 and the partial top surface of the cupped lower electrode 500".

[0099] The capacitor dielectric layer 900 can comprise a high dielectric constant dielectric material, such as hafnium oxide (HfO), zirconium oxide (ZrO), aluminum oxide (AlO), aluminum nitride (AlN), titanium oxide (TiO), lanthanum oxide (LaO), yttrium oxide (YO), gadolinium oxide (GdO), tantalum oxide (TaO), or combinations thereof.

[0100] Next, as shown in Figure 21 , an upper electrode 1000 is formed on the surface of the capacitor dielectric layer 900. In some embodiments, the upper electrode 1000 covers the surface of the capacitor dielectric layer 900.

[0101] The upper electrode 1000 can comprise a metal, a metal silicide, a metal nitride, or a metal alloy, such as titanium nitride (TiN), tantalum nitride (TaN), tungsten (W), titanium tungsten (TiW), aluminum (Al), copper (Cu).

[0102] In summary, the embodiments of the present application can protect the lower electrode from being damaged by the process by forming an annealing oxide layer. By sandwiching the annealing oxide layer between the partial surface of the lower electrode and the capacitor dielectric layer, the work function can be reduced and the leakage current can be inhibited. By forming a plurality of cup-shaped lower electrodes and the annealing oxide layer before forming the protective layer, the risk of significantly reducing the height of the cup-shaped lower electrode when removing the template layer can be reduced. When removing the template layer, the upper support layer and the middle support layer can be removed in the same step, which can reduce the complexity of the process. The reinforcement structure formed by the lower support layer, the middle support layer, and the upper support layer can increase the mechanical strength of the capacitor to avoid the phenomenon of deformation or even tilting of the capacitor. In summary, the embodiments of the present application can improve the capacitance value.

[0103] Although the present application has been disclosed in the foregoing embodiments, it is not intended to limit the present application. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined by the claims.

Claims

1. A capacitor, characterized in that, include: Multiple cup-shaped lower electrodes are located on a substrate; A capacitor dielectric layer compliantly covers the inner and outer surfaces of the cup-shaped lower electrode; An annealed oxide layer is sandwiched between the inner surface of the cup-shaped lower electrode and the capacitor dielectric layer, and also sandwiched between a portion of the outer surface of the cup-shaped lower electrode and the capacitor dielectric layer. One upper electrode covers the surface of the capacitor dielectric layer; as well as A support layer is located between the outer surfaces of the cup-shaped lower electrode to connect the cup-shaped lower electrode, wherein the support layer comprises: An upper support layer is connected to the upper part of the outer surface of the cup-shaped lower electrode, wherein the annealed oxide layer does not contact the upper support layer; A support layer, connecting the middle of the outer surface of the cup-shaped lower electrode; and A support layer is connected to the lower part of the outer surface of the cup-shaped lower electrode.

2. The capacitor according to claim 1, characterized in that, The annealed oxide layer is also sandwiched between a portion of the top surface of the cup-shaped lower electrode and the capacitor dielectric layer.

3. The capacitor according to claim 1, characterized in that, The annealed oxide layer contains the metallic elements of the cup-shaped lower electrode.

4. The capacitor according to claim 1, characterized in that, The upper width of the sidewall of the cup-shaped lower electrode, which does not have the upper support layer on its outer surface, is smaller than its lower width.

5. A method for forming a capacitor, characterized in that, include: Provide a substrate; A support layer and a template layer are sequentially formed on the substrate; Multiple cup-shaped openings are formed in the template layer and the support layer; An electrode material layer is formed in the cup-shaped opening and on the top surface of the support layer: Remove the lower electrode material layer on the top surface of the support layer, and the remaining lower electrode material layer serves as a plurality of cup-shaped lower electrodes; Remove the upper part of the support layer so that the sidewalls of any two cup-shaped lower electrodes protrude from the top surface of the support layer; An oxide layer is formed on the surface of the cup-shaped lower electrode and on the surface of the support layer; Anneal the oxide layer to form an annealed oxide layer; A protective layer is formed on the annealed oxide layer, wherein the protective layer closes the top of the cup-shaped opening; A shield is formed on the top surface of a portion of the cup-shaped lower electrode; Remove the protective layer and the support layer except those below the mask; Remove the remaining protective layer, the template layer, and a portion of the annealed oxide layer, so that the remaining annealed oxide layer adheres to the inner surface of the cup-shaped lower electrode; A capacitor dielectric layer is formed on the surface of the cup-shaped lower electrode, the surface of the remaining annealed oxide layer, and the surface of the support layer; and An upper electrode is formed on the surface of the capacitor dielectric layer.

6. The method for forming a capacitor according to claim 5, characterized in that, The step of removing the lower electrode material layer on the top surface of the support layer is performed simultaneously with the step of removing the upper part of the support layer.

7. The method for forming a capacitor according to claim 5, characterized in that, The concurrent steps include dry etching with a selective etching ratio of 10:1 to 30:1 for the support layer using the cup-shaped lower electrode.

8. The method for forming a capacitor according to claim 5, characterized in that, The step of removing the protective layer and the support layer outside the mask also includes simultaneously removing the annealed oxide layer outside the mask and located outside the cup-shaped lower electrode.

9. The method for forming a capacitor according to claim 5, characterized in that, The shield covers a portion of each cup-shaped lower electrode and exposes another portion of each cup-shaped lower electrode.

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