Method for forming capacitor electrodes

Abstract

A method for forming a capacitor electrode according to an embodiment of the present invention may include the steps of preparing a substrate, spraying a source including titanium (Ti) onto the substrate to form a first thin film including titanium (Ti), and spraying a source including a noble metal element or copper (Cu) onto the substrate to form a second thin film. Therefore, according to the embodiment of the present invention, it is possible to suppress or prevent damage to the underlayer during the formation of the electrode, and it is also possible to reduce the resistivity of the electrode, thereby improving the electrical characteristics of the electrode. Furthermore, damage to the underlayer is suppressed or prevented, and the electrical characteristics of the electrodes are improved, resulting in improved quality characteristics of the capacitor.

Description

[Technical field]

[0001] The present invention relates to a method for forming a capacitor electrode, and more particularly to a method for forming a capacitor electrode that can suppress or prevent damage to an underlying layer. [Background technology]

[0002] A capacitor applied to a semiconductor device includes a lower electrode formed on a substrate, a dielectric layer formed on the lower electrode, and an upper electrode formed on the dielectric layer, where each of the upper electrode and the lower electrode is formed by stacking a titanium nitride (TiN) thin film and a tungsten (W) thin film.

[0003] When forming a titanium nitride (TiN) thin film, a source containing TiCl4 is used, and when forming a tungsten (W) thin film, a source containing WF6 is used.

[0004] However, when forming the titanium nitride (TiN) thin film and the tungsten (W) thin film, respectively, chlorine (Cl) and fluorine (F) contained in the source penetrate into the underlayer, for example, the contact layer made of metal oxide, causing damage to the underlayer, i.e., the contact layer, which leads to a problem of degraded capacitor characteristics. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent No. 10-1110077 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a method for forming a capacitor electrode that can suppress or prevent damage to an underlying layer.

[0007] The present invention provides a method for forming a capacitor electrode that can improve electrical characteristics. [Means for solving the problem]

[0008] A method for forming a capacitor electrode according to an embodiment of the present invention may include the steps of preparing a substrate, spraying a source including titanium (Ti) onto the substrate to form a first thin film including titanium (Ti), and spraying a source including a noble metal element or copper (Cu) onto the substrate to form a second thin film.

[0009] The step of forming the first thin film and the step of forming the second thin film may be repeated alternately.

[0010] The step of forming the second thin film may be performed before the step of forming the first thin film.

[0011] In the step of forming the first thin film, deposition of TiN atomic layers may be performed multiple times in succession.

[0012] In the step of forming the second thin film, a plurality of deposition cycles may be carried out in succession.

[0013] The step of forming the first thin film may be repeated more times than the step of forming the second thin film.

[0014] The ratio (T1:T2) of the number of times (T2) the step of forming the first thin film is performed to the number of times (T1) the step of forming the second thin film is performed may be adjusted to 1:1 to 10:1.

[0015] The source containing the noble metal element may be a precursor containing at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo).

[0016] The step of forming the second thin film may include the steps of injecting a reducing gas after injecting a source containing a precious metal element or copper (Cu), and activating the reducing gas using plasma.

[0017] The step of forming the second thin film may include a step of injecting a reducing gas after injecting a source containing a noble metal element or copper (Cu), and a step of exposing the substrate to plasma. Effect of the Invention

[0018] According to the embodiment of the present invention, it is possible to suppress or prevent damage to the underlayer when forming the electrode, and it is also possible to reduce the resistivity of the electrode, thereby improving the electrical characteristics of the electrode.

[0019] Furthermore, damage to the underlayer is suppressed or prevented, and the electrical characteristics of the electrodes are improved, resulting in improved quality characteristics of the capacitor. [Brief description of the drawings]

[0020] [Figure 1] 1 is a conceptual diagram showing a capacitor having electrodes formed by a method for forming a capacitor electrode according to an embodiment of the present invention; [Diagram 2] 1 is a diagram showing a bottom electrode formed by a method according to an embodiment of the present invention on a substrate having an underlayer formed on its upper surface. [Diagram 3] 1A to 1C are conceptual diagrams for explaining a method for forming a lower electrode according to an embodiment of the present invention. [Figure 4]13 is a diagram showing a lower electrode formed on a substrate having an undercoat layer formed on the upper surface thereof by a method according to a modified example of the embodiment. FIG. [Diagram 5] 10A to 10C are conceptual diagrams for explaining a method for forming a lower electrode by a method according to a modified example of the embodiment. [Figure 6] 1 is a diagram showing a capacitor having a lower electrode formed on a substrate having a trench formed therein; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be embodied in various different forms. The following embodiments are provided only to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention. In order to explain the embodiments of the present invention, the drawings may be exaggerated, and the same reference numerals in the drawings refer to the same components.

[0022] FIG. 1 is a conceptual diagram showing a capacitor having electrodes formed by a method for forming a capacitor electrode according to an embodiment of the present invention.

[0023] 1, the capacitor 100 may include a substrate 110, a lower electrode 130 formed on the substrate 110, a dielectric layer 140 formed on the lower electrode 130, and an upper electrode 150 formed on the dielectric layer 140. The capacitor 100 may also include an underlayer 120 formed below the lower electrode 130, and the underlayer 120 may be, for example, a contact layer.

[0024] The substrate 110 may be a semiconductor substrate. More specifically, the substrate 110 may be a wafer, or may be any one of a Si wafer, a GaAs wafer, and a SiGe wafer.

[0025] The underlayer 120 is a layer formed between the substrate 110 and the lower electrode 130, and may be, for example, a contact layer. Such an underlayer 120 may be formed of a metal oxide, for example, a SiO2 thin film or an Al2O3 thin film.

[0026] The dielectric layer 130 is formed between the lower electrode 130 and the upper electrode 150, and may be formed of a dielectric material including a metal oxide. More specifically, the dielectric layer 140 may be formed of any one of ZrO2, Al2O3, TiO2, TaO2, and HfO2. The dielectric layer 140 may be formed by an atomic layer deposition (ALD) method or a chemical vapor deposition (CVD) method.

[0027] At least one of the lower electrode 130 and the upper electrode 150 is formed by laminating a first thin film containing titanium (Ti) and a second thin film containing a noble metal element or copper (Cu).

[0028] When the second thin film is formed from a thin film containing a noble metal element, a precursor containing a noble metal element is used as a source. More specifically, a precursor containing at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo) is used as a source to form at least one of the lower electrode 130 and the upper electrode 150. More specifically, a precursor containing at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo), and not containing chlorine (Cl: Chlorine) and fluorine (F: Fluorine), is used as a source.

[0029] For example, as a precursor source containing ruthenium (Ru), a Bis(ethylcyclopentadienyl)ruthenium (EtCp)2Ru precursor compound can be used. As a precursor source containing platinum (Pt), for example, a material containing at least one of (TriMethyl)Methylcyclopentadienylplatinum and (TriMethyl)cyclopentadienylplatinum such as (C5H5)Pt(CH3)3 can be used. As a precursor source containing gold (Au), for example, gold hydroxide Au(OH)3 can be used. As a precursor source containing silver (Ag), for example, a material containing at least one of silver nitrate (AgNO3) and silver nitrite (AgNO2) can be used. As a precursor source containing rhodium (Rh), for example, Rh4(CO) 12 Materials containing the above can be used. As a precursor source containing palladium (Pd), for example, a material containing at least one of Pd(NO3)2, Pd(OAc)2, and Pd(acac)2 can be used. As a precursor source containing osmium (Os), for example, at least one of (methylcyclopentadienyl)osmium(methyl)(dicarbonyl), (ethylcyclopentadienyl)osmium(methyl)(dicarbonyl), and (propylcyclopentadienyl)osmium(methyl)(dicarbonyl) can be used. As a precursor source containing iridium (Ir), Ir(acac)3 and Ir4(CO) 12 A material containing at least one of the above can be used. As a precursor source containing yttrium (Yi), for example, tris-(methylcyclopentadienyl) yttrium can be used. As a precursor source containing molybdenum (Mo), for example, a material containing at least one of molybdenum hexacarbonyl and molybdenum pentachloride can be used.

[0030] In this way, when forming at least one of the lower electrode 130 and the upper electrode 150 by forming the second thin film containing a precious metal element, in the embodiment, a precursor that does not contain chlorine (Cl: Chlorine) and fluorine (F: Fluorine) and contains at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi) and molybdenum (Mo) is used as a source to form the electrode. Therefore, it is possible to suppress or prevent the layer formed under the electrode formed using the above-mentioned source from being damaged by chlorine (Cl) and fluorine (F). For example, when the lower electrode 130 is formed using a precursor that contains the above-mentioned precious metal and does not contain chlorine (Cl) and fluorine (F) as a source, it is possible to suppress or prevent chlorine (Cl) and fluorine (F) from penetrating and damaging the underlayer 120, for example, the contact layer, during the formation of the lower electrode 130. As another example, when the upper electrode 150 is formed using a precursor containing the above-mentioned noble metal and not containing chlorine (Cl) and fluorine (F) as a source, it is possible to suppress or prevent the layer below the upper electrode 150, i.e., the dielectric layer 140, from being damaged by chlorine (Cl) and fluorine (F).

[0031] In the above, the second thin film is formed using a precursor source containing a noble metal element, but the second thin film may be formed using a precursor source containing copper (Cu). In this case, an organometallic compound or a material containing F or Cl can be used as the precursor source containing copper (Cu).

[0032] Here, as the copper (Cu)-containing precursor source, which is an organometallic compound, for example, a material containing at least one of copper (II)-2,2,6,6-tetramethyl-3,5-heptandionate [Cu(thd)2] and copper (II) hexafluoroacetylacetonate [Cu(hfac)2] can be used. As the copper precursor source containing F or Cl, a material containing at least one of CuCl1, CuCl2, CuF1, CuF2, CuBr1, CuBr2, CuI1, or CuI2 can be used.

[0033] Furthermore, the precious metal elements ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo) and copper (Cu) have lower resistivity than tungsten (W), which is a source that has been used conventionally in forming the upper electrode 150 and the lower electrode 130. Therefore, at least one of the upper electrode 150 and the lower electrode 130 formed using the above-mentioned precious metal material has a lower resistivity than conventionally, which has the effect of improving electrical characteristics.

[0034] Hereinafter, a method for forming a capacitor electrode according to an embodiment of the present invention will be described with reference to Figures 2 and 3. Here, a case will be described in which a lower electrode 130 is formed on an upper part of a substrate 110, the upper part of which is an underlayer 120 made of a metal oxide. Since the methods for forming the lower electrode 130 and the upper electrode 150 are similar, the method for forming the lower electrode 130 will be described and a detailed description of the method for forming the upper electrode 150 will be omitted.

[0035] Fig. 2 is a diagram showing a lower electrode formed by a method according to an embodiment of the present invention on a substrate having an underlayer formed on its upper surface. Fig. 3 is a conceptual diagram for explaining a method for forming a lower electrode by a method according to an embodiment of the present invention. In Fig. 3, "on" may mean injecting a precursor or gas, and "off" may mean interrupting or ending the injection of the precursor or gas.

[0036] 2, the lower electrode 130 may include a first thin film 131 containing titanium (Ti) and a second thin film 132 containing a precious metal element formed on the first thin film 131. Here, the first thin film 131 may be, for example, a TiN thin film. The first thin film 131 may be formed by a deposition method using a source containing titanium (Ti), and the second thin film 132 may be formed by a deposition method using a source containing a precious metal element or copper (Cu).

[0037] The lower electrode 130 may include a plurality (or a plurality of layers) of first thin films 131 and a plurality (or a plurality of layers) of second thin films 132. In this case, as shown in FIG. 2, the first thin films 131 and the second thin films 132 may be alternately laminated to form the lower electrode 130. The total number of the first thin films 131 included in the lower electrode 130 may be greater than that of the second thin films 132. The number of the first thin films 131 that are continuously laminated may be greater than the number of the second thin films 132 that are continuously laminated. The thin film that is first deposited when forming the lower electrode 130 may be the first thin film 131 as shown in FIG. 2. In other words, when forming the lower electrode 130 on the underlayer 120, the thin film that is first deposited on the upper surface of the underlayer 120 may be the first thin film 131.

[0038] 2, five layers of first thin films 131 may be formed on the upper surface of the underlayer 120, one layer of second thin film 132 may be continuously formed on the first thin films 131, and the formation of the five layers of first thin films 131 and the formation of one layer of second thin film 132 may be alternately repeated multiple times to form the lower electrode 130. Therefore, the number of layers of the first thin films 131 may be greater than the number of layers of the second thin films 132 provided in the lower electrode 130, and the number of layers of the first thin films 131 that are continuously stacked may be greater than the number of layers of the second thin films 132 that are continuously stacked.

[0039] In the above example, the second thin film 132 is not continuously formed as a plurality of layers, but is formed as one layer or a single layer. However, the present invention is not limited to this, and a plurality of layers of the second thin film 132 may be continuously formed according to the number of thin films containing titanium (Ti), i.e., the first thin film 131, which are continuously stacked. For example, when ten layers of the first thin film 131 are continuously formed, five layers of the second thin film 132 may be continuously formed. That is, after ten layers of the first thin film 131 are formed on the upper surface of the underlayer 120, five layers of the second thin film 132 may be continuously formed on the first thin film 131, and the formation of the ten layers of the first thin film 131 and the formation of the five layers of the second thin film 132 may be alternately repeated several times to form the lower electrode 130.

[0040] Here, each of the multiple layers of the first thin film 131 or the multiple layers of the second thin film 132 is formed by repeating a deposition cycle multiple times. In Fig. 2, the first thin films 131 deposited by each deposition cycle are shown as multiple layers in order to distinguish them from one another, but the stacked multiple first thin films 131 may be integral.

[0041] Referring to FIG. 3, the process of forming the lower electrode 130 on the substrate 110 or on the underlayer 120 includes a process cycle C of forming a first thin film 131 and a second thin film 132. p And process cycle C pThat is, the process of forming the lower electrode 130 is performed in a plurality of process cycles C p :C p1 , C p2 , …, C pn-1 , C pn A plurality of process cycles C p :C p1 , C p2 , …, C pn-1 , C pn Each of the process cycles C1 includes a first cycle C2 for depositing a first thin film 131 including titanium (Ti) and a second cycle C3 for depositing a second thin film 132 including a noble metal element or copper (Cu). p :C p1 , C p2 , …, C pn-1 , C pn Each of the cycles includes a step of forming a first thin film 131 and a step of forming a second thin film 132. The step of forming the first thin film 131 includes a first cycle C1, and the step of forming the second thin film 132 includes a second cycle C2.

[0042] For ease of explanation, the following describes a plurality of process cycles C performed in sequence. p :C p1 , C p2 , …, C pn-1 , C pn For the first process cycle C p1 , 2nd process cycle C p2 , the (n-1)th process cycle C pn-1 , nth process cycle C pn Here, "n" may be the final process cycle. The final number (n) may vary depending on the target number of executions of the process cycle, and the target number of executions of the process cycle may vary depending on the target thickness of the bottom electrode 130 to be manufactured.

[0043] Process cycle C for forming the lower electrode 130 of the capacitor 100 pThe method includes a step of forming a first thin film 131 by injecting a source containing titanium (Ti) and a step of forming a second thin film 132 by injecting a source which is a precursor containing a noble metal element or copper (Cu), and the steps of forming the first thin film 131 and the second thin film 132 are alternately performed multiple times.

[0044] Referring to FIG. 3, process cycle C p Here, we will explain in more detail. At this time, the first process cycle C p1 This will be explained using the following example.

[0045] Referring to FIG. 3, the first process cycle C p1 The process includes a first cycle C1 for depositing a first thin film 131 containing titanium (Ti) and a second cycle C2 for depositing a second thin film 132 containing a noble metal element or copper (Cu). In this case, the first cycle C1 may be performed before the second cycle C2. For this reason, the multiple process cycles C p These can be performed in the order of "first cycle C1 - second cycle C2".

[0046] Needless to say, the order of carrying out the first cycle C1 and the second cycle C2 is not limited to this. That is, the second cycle C2 may be carried out before the first cycle C1. That is, the multiple process cycles C p may be performed in the order of "second cycle C2 - first cycle C1".

[0047] The first cycle C1 may include a step of injecting a first source containing Ti (titanium), a step of injecting a purge gas (first purge), a step of injecting a reactant, and a step of injecting a purge gas (second purge). That is, the first cycle C1 may be a cycle performed in the order of "injection of the first source containing Ti (titanium)-injection of a purge gas (first purge)-injection of a reactant-injection of a purge gas (second purge)". For example, a gas containing TiCl4 can be used as the first source containing Ti (titanium). And, a gas containing nitrogen (N), for example, a gas containing NH3 can be used as the reactant. Also, Ar gas can be used as the purge gas. A TiN atomic layer, i.e., a first thin film 131, is deposited and formed by the atomic layer deposition (ALD) method using such a first cycle C1.

[0048] The first cycle C1 for depositing the first thin film 131 by such a method can be named a "TiN deposition cycle."

[0049] The second cycle C2 may include a step of injecting a second source containing a precious metal element or copper (Cu), a step of injecting a purge gas (first purge), a step of injecting a reducing gas, and a step of injecting a purge gas (second purge).

[0050] In this case, the precious metal element used as the second source may be a precursor containing at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi) and molybdenum (Mo) and not containing chlorine (Cl) and fluorine (F).The second source, which is a precursor containing a precious metal element or copper (Cu), may be in a liquid or gas state.

[0051] In the precursor containing a noble metal element used as the second source, the precursor containing ruthenium (Ru) may be bis(ethylcyclopentadienyl)ruthenium ((EtCp)2Ru), and the precursor containing gold (Au) may be, for example, gold hydroxide Au(OH)3. The precursor containing silver (Ag) may be, for example, a material containing at least one of silver nitrate (AgNO3) and silver nitrite (AgNO2). The precursor containing rhodium (Rh) may be, for example, Rh4(CO). 12 Materials containing the above can be used. As a precursor containing palladium (Pd), for example, a material containing at least one of Pd(NO3)2, Pd(OAc)2, and Pd(acac)2 can be used. As a precursor containing osmium (Os), for example, at least one of (methylcyclopentadienyl)osmium(methyl)(dicarbonyl), (ethylcyclopentadienyl)osmium(methyl)(dicarbonyl), and (propylcyclopentadienyl)osmium(methyl)(dicarbonyl) can be used. As a precursor containing iridium (Ir), Ir(acac)3 and Ir4(CO) 12 A material containing at least one of the following can be used. As a precursor containing yttrium (Yi), for example, tris-(methylcyclopentadienyl) yttrium can be used. As a precursor source containing molybdenum (Mo), for example, a material containing at least one of molybdenum hexacarbonyl and molybdenum pentachloride can be used.

[0052] As a precursor containing copper (Cu), a material containing at least one of copper(II)-2,2,6,6-tetramethyl-3,5-heptandionate [Cu(thd)2] and copper(II) hexafluoroacetylacetonate [Cu(hfac)2] can be used, or a material containing at least one of CuCl1, CuCl2, CuF1, CuF2, CuBr1, CuBr2, CuI1, and CuI2 can be used.

[0053] In the following, an example will be described in which a precursor containing a precious metal element is used as the second source, and the second thin film 132 is formed from a thin film containing a precious metal element. More specifically, an example will be described in which a precursor containing ruthenium (Ru) is used as the second source, and the second thin film 132 is formed from a ruthenium (Ru) thin film.

[0054] The purge gas may be the same as that used in the first cycle C1, that is, argon (Ar) gas may be used as the purge gas.

[0055] The reducing gas is a gas injected to remove impurities contained in the second thin film 132, for example, a ruthenium (Ru) thin film, and a gas containing oxygen (O) or hydrogen (H) can be used. More specifically, the gas containing oxygen (O) may be O2 gas, and the gas containing hydrogen (H) may be H2 gas. Such a reducing gas can be named a gas for removing impurities.

[0056] During or after the injection of the reducing gas, it is preferable to generate plasma or apply heat to the thin film deposition space, for example, the chamber, so that the substrate is plasma-treated or heat-treated. The reducing gas may be activated by the generated plasma or heat.

[0057] In this manner, the second cycle C2 for forming the second thin film 132 includes "injection of second source-injection of purge gas (first purge)-injection of reducing gas-injection of purge gas (second purge)", and the second thin film 132 is formed by deposition through the second cycle C2. The second cycle C2 for forming the second thin film 132 using a source containing a precious metal element in this manner can be named a "precious metal deposition cycle".

[0058] In an embodiment, in carrying out the first cycle C1 and the second cycle C2 as described above, one process cycle C p The number of times (T1) the first cycle C1 is performed is adjusted to be greater than the number of times (T2) the second cycle C2 is performed. In other words, the number of times (T2) the first cycle C1 is performed is adjusted to be greater than the number of times (T2) the second cycle C2 is performed. p The number of times (T2) the step of forming the thin precious metal film included in is performed is adjusted to be smaller than the number of times (T1) the step of forming the thin TiN film is performed.

[0059] In this case, the ratio (T1:T2) of the number of times the first cycle C1 is performed (T1) to the number of times the second cycle C2 is performed (T2) is adjusted to be 1:1 to 10:1 (T1:T2=1:1 to 10:1). More preferably, the ratio (T1:T2) of the number of times the first cycle C1 is performed (T1) to the number of times the second cycle C2 is performed (T2) is adjusted to be 3:1 to 8:1 (T1:T2=3:1 to 8:1). In other words, the ratio (T1:T2) of the number of times the TiN thin film formation step is performed (T1) to the number of times the precious metal thin film formation step is performed (T2) is adjusted to be 1:1 to 10:1, more preferably 3:1 to 8:1.

[0060] The first cycle C1 as described above can be named a "TiN thin film deposition cycle", and the second cycle C2 can be named a "noble metal thin film cycle". Therefore, the "ratio (T1:T2) of the number of times the first cycle C1 is performed (T1) to the number of times the second cycle C2 is performed (T2)" can be explained as the "ratio (T1:T2) of the number of times the TiN thin film deposition cycle C1 is performed (T1) to the number of times the noble metal thin film deposition cycle C2 is performed (T2)". This can be explained as the ratio (T1:T2) of the number of times the TiN thin film deposition cycle C1 is performed (T1) to the number of times the noble metal thin film deposition cycle C2 is performed (T2) is adjusted to be 1:1 to 10:1, more preferably 3:1 to 8:1.

[0061] In the following, for ease of explanation, the "ratio (T1:T2) of the number of times the first cycle C1 is performed to the number of times (T2) the second cycle C2 is performed" will be abbreviated to "the ratio (T1:T2) of the number of times the first and second cycles are performed."

[0062] For a more detailed description of the method for forming the lower electrode 130, a case where the ratio (T1:T2) of the number of times the first and second cycles are performed is 5:1 will be described with reference to FIG. 3. Referring to FIG. 3, a plurality of process cycles C p :C p1 , C p2 , …, C pn-1 , C pn Each of the process cycles C1 and C2 may include a first cycle C1 and a second cycle C2, and the ratio (T1:T2) of the number of times the first cycle is performed to the number of times the second cycle is performed may be 5:1. p :C p1 , C p2 , …, C pn-1 , C pn Each of the cycles may include five first cycles C1 and one second cycle C2, as shown in FIG.

[0063] 1st process cycle C p1For example, first, the first cycle C1 is performed five times. Therefore, as shown in FIG. 2, five layers of the first thin film 131 are deposited on the upper part of the substrate 110 or the upper part of the underlayer 120. Five first cycles C1 are performed continuously, and when the fifth first cycle C1 is completed, one second cycle C2 is performed. Therefore, one layer of the second thin film 132, i.e., a ruthenium (Ru) thin film, is deposited on the first thin film 131. Then, as described above, after five consecutive first cycles C1 are performed, one second cycle C2 is performed, so that the ratio (T1:T2) of the number of times the first and second cycles are performed is 5:1.

[0064] In this way, the first process cycle C p1 When the second cycle C2 is completed, the second process cycle C p2 At this time, the first process cycle C p1 The second process cycle C is carried out in the same ratio as the ratio (T1:T2) of the number of times the first and second cycles were carried out in p2 It is preferable to carry out the second process cycle C. p2 When carrying out the above, the ratio of the number of times the first and second cycles are carried out (T1:T2) is set to 5:1.

[0065] Second process cycle C p2 When the second cycle C2 is completed, the next process cycle C is carried out in the same manner. p3 , …, C pn-1 , C pn At this time, as shown in FIG. 3, the process cycle is carried out until the target number of cycles (n) to be carried out is reached.

[0066] Thus, in the embodiment, when forming the lower electrode 130, a noble metal precursor that does not contain chlorine (Cl) and fluorine (F) is used to form the second thin film 132. That is, the second thin film 132 is formed using a precursor that contains at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi) and molybdenum (Mo) and does not contain chlorine (Cl) and fluorine (F) as a second source. Therefore, it is possible to suppress or prevent the underlayer 120 formed under the lower electrode 130, for example, the contact layer, from being damaged by chlorine (Cl) and fluorine (F). That is, it is possible to suppress or prevent damage to the underlayer 120 caused by chlorine (Cl) and fluorine (F) when forming the lower electrode 130. This can suppress or prevent the characteristics of the capacitor 100 from being deteriorated due to damage to the underlayer 120 .

[0067] By forming the lower electrode 130 by the method according to the embodiment, damage to the underlayer 120 can be further suppressed compared to the conventional method. To explain this more specifically, in the case of the embodiment, the first thin film 131 is first formed on the underlayer 120 using a TiCl4 source, and the second thin film 132 containing a precious metal element is formed on the TiN thin film. Therefore, when the first thin film 131 is formed on the underlayer 120, there is a risk that slight damage due to chlorine (Cl) may occur.

[0068] However, this damage is much less than that in the conventional method, in which the two layers are formed using sources containing chlorine (Cl) and fluorine (F). That is, in the conventional method, a TiN thin film is formed using a TiCl4 source, a tungsten (W) thin film is formed using a WF6 source, and the TiN thin film and the tungsten (W) thin film are alternately laminated to form the lower electrode. In other words, one of the two types of thin films constituting the lower electrode is formed using a source containing chlorine (Cl), and the other is formed using a source containing fluorine (F). Therefore, when forming the TiN thin film and the tungsten (W) thin film, there is a risk that chlorine (Cl) and fluorine (F) will penetrate into the underlayer and damage the underlayer.

[0069] In contrast, in the embodiment, one of the thin films constituting the lower electrode 130, i.e., the first thin film 131 containing a precious metal element, is formed using a source that does not contain chlorine (Cl) and fluorine (F). Therefore, damage to the underlayer 120 caused by chlorine (Cl) and fluorine (F) during the formation of the lower electrode 130 can be further suppressed compared to the conventional case.

[0070] In the above description, the second thin film 132 is formed from a thin film containing a precious metal element, but the second thin film 132 may be formed from a thin film containing copper (Cu).

[0071] In this way, by forming the lower electrode 130 so as to contain at least one of precious metal elements selected from ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi) and molybdenum (Mo) or copper (Cu), it is possible to reduce the resistivity of the lower electrode 130. That is, compared to the conventional case in which the lower electrode 130 is formed from tungsten (W), the embodiment has the effect of lowering the resistivity of the lower electrode 130 and improving the electrical characteristics.

[0072] Fig. 4 is a diagram showing a lower electrode formed by a method according to a modified embodiment on a substrate having an underlayer formed on the upper surface thereof, and Fig. 5 is a conceptual diagram for explaining a method for forming a lower electrode by a method according to a modified embodiment.

[0073] In the above-described embodiment, the step of depositing a TiN thin film, i.e., the first cycle C1, is performed first when forming the lower electrode 130. However, the present invention is not limited to this, and the step of depositing a thin film containing a noble metal element or copper (Cu), i.e., the second cycle C2, may be performed first. Therefore, the layer formed on the upper surface of the underlayer 120 or the layer formed so as to be in direct contact with the underlayer 120 may be the second thin film 132, as shown in FIG.

[0074] Hereinafter, a method for forming a lower electrode 130 on an underlayer 120 by a method according to a modified example will be described with reference to Fig. 4 and Fig. 5. At this time, descriptions that overlap with the contents described in the embodiment will be omitted or will be described briefly.

[0075] Referring to FIG. 5, the process of forming the lower electrode 130 includes a process cycle C of forming a second thin film 132 and a first thin film 131 on the substrate 110 or the underlayer 120. p The process of forming the lower electrode 130 includes a plurality of process cycles C p Includes.

[0076] Multiple process cycles C p :C p1 , C p2 , …, C pn-1 , C pn Each of the process cycles C includes a second cycle C2 for forming the second thin film 132 and a first cycle C1 for forming the first thin film 131. p :C p1 , C p2 , …, C pn-1 , C pnEach of the steps includes forming a thin film containing a noble metal element or copper (Cu) and forming a thin film containing titanium (Ti).

[0077] In this case, the second cycle C2 is performed before the first cycle C1 is performed. That is, the step of forming a thin film containing a noble metal element or copper (Cu) is performed before the step of forming a TiN thin film. In other words, the second cycle C2 is performed first so that the thin film deposited on the upper surface of the underlayer 120 or the thin film in contact with the underlayer 120 becomes the second thin film 132.

[0078] Then, as in the embodiment described above, the second cycle C2 and the first cycle C1 are alternately performed multiple times. p The number of times (T2) the second cycle C2 is performed is adjusted to be smaller than the number of times (T1) the first cycle C1 is performed. That is, one process cycle C p The number of times (T2) the second cycle C2 is performed consecutively is adjusted to be smaller than the number of times (T1) the first cycle C1 is performed consecutively.

[0079] Furthermore, the ratio (T1:T2) of the number of times the first cycle C1 is performed (T1) to the number of times the second cycle C2 is performed (T2) is adjusted to be 1:1 to 10:1 (T1:T2=1:1 to 10:1), more preferably 3:1 to 8:1 (T1:T2=3:1 to 8:1).

[0080] More specifically, referring to FIG. 5, a plurality of process cycles C p :C p1 , C p2 , …, C pn-1 , C pn Each of the first process cycles C may include one second cycle C2 and five first cycles C1. p1For example, first, the second cycle C2 is performed once. Therefore, one layer of the second thin film 132 is deposited on the underlayer 120 as shown in FIG. 4. After one second cycle C2 is completed, the first cycle C1 is performed five times. Therefore, five layers of the first thin film 131 are formed on the second thin film 132, for example, a ruthenium (Ru) thin film. Then, as described above, after one second cycle C2 is performed, the first cycle C1 is performed five times in succession, so that the ratio (T1:T2) of the number of times the first and second cycles are performed is 5:1.

[0081] Such a first process cycle C p1 When the first cycle C1 is completed, the second process cycle C p2 At this time, the first process cycle C p1 The second process cycle C is carried out in the same ratio as the ratio (T1:T2) of the number of times the first and second cycles were carried out in p2 It is preferable to carry out the following.

[0082] Second process cycle C p2 When the second cycle C2 is completed, the next process cycle C is carried out in the same manner. p3 , …, C pn-1 , C pn At this time, as shown in FIG. 5, the process cycle is carried out until the target number of cycles (n) to be carried out is reached.

[0083] Thus, in the modified example, when forming the lower electrode 130 on the underlayer 120, the second thin film 132 is first formed by deposition using a second source that does not contain chlorine (Cl: Chlorine) and fluorine (F: Fluorine).

[0084] Therefore, in the case of the modified example, damage to the underlayer 120 can be suppressed or prevented more effectively than in the embodiment. That is, in the case of the embodiment, the first thin film 131 is formed on the underlayer 120 first using a TiCl4 source, and the second thin film 132 is formed on the first thin film 131. In contrast, in the case of the modified example, when forming the lower electrode 130, the second thin film 132 is formed first. That is, the second thin film 132 is formed first on the underlayer 120 using a precursor that contains at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo), and does not contain chlorine (Cl: Chlorine) and fluorine (F: Fluorine). Then, the first thin film 131 is formed on the second thin film 132 using TiCl4 as a source. Therefore, by covering the base layer 120 with the second thin film 132, it is possible to prevent the base layer 120 from being exposed to chlorine (Cl) during the formation of the first thin film 131. Therefore, damage to the base layer 120 can be suppressed or prevented more effectively than in the embodiment.

[0085] FIG. 6 is a diagram showing a capacitor having a lower electrode formed on a substrate having a trench formed therein.

[0086] In the above description, the lower electrode 130 for a capacitor is formed on a flat substrate 110. However, the present invention is not limited thereto, and as shown in FIG. 6, a capacitor may be manufactured by forming the lower electrode 130 on the substrate 110 having the trench 111 by the method according to the embodiment as shown in FIG. 3. That is, the underlayer 120, for example, a contact layer, may be formed on the substrate 110 having the trench 111, and the lower electrode 130 may be formed on the contact layer by the method according to the embodiment. Needless to say, the formation of the lower electrode on the substrate 110 having the trench 111 is not limited to the embodiment of FIG. 3, and may be formed by the method according to the modified example of FIG. 5.

[0087] In the above, the method according to the embodiment and the modified example has been described as an example of forming the lower electrode 130 of the capacitor 100. However, the method according to the embodiment and the modified example can be applied to form the upper electrode 150, and can be applied to both the formation of the upper electrode 150 and the lower electrode 130.

[0088] Thus, in the embodiment, when at least one of the upper electrode 150 and the lower electrode 130 is formed, the first thin film 131 and the second thin film 132 are laminated to form them. At this time, when forming the second thin film 132, a precursor source containing a precious metal element that does not contain chlorine (Cl) and fluorine (F) is used. That is, the second thin film 132 is formed using a precursor that contains at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo) and does not contain chlorine (Cl) and fluorine (F) as a second source. This makes it possible to suppress or prevent the underlayer 120 formed under the upper electrode 150 or the lower electrode 130 from being damaged by chlorine (Cl) and fluorine (F).

[0089] In addition, when forming at least one of the upper electrode 150 and the lower electrode 130, the second thin film 132 containing at least one of the noble metal elements ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi) and molybdenum (Mo) or copper (Cu) is provided so as to be included. This can reduce the resistivity of at least one of the upper electrode 150 and the lower electrode 130, thereby improving the electrical characteristics.

[0090] In this way, damage to the underlayer 120 is suppressed or prevented, and the electrical characteristics of the electrodes are improved, thereby improving the quality characteristics of the capacitor 100. [Industrial Applicability]

[0091] According to the embodiment of the present invention, damage to the underlayer can be suppressed or prevented during the formation of the electrode, and the specific resistance of the electrode can be reduced, thereby improving the electrical characteristics of the electrode.

Claims

1. The steps include preparing the circuit board and The steps include performing a process cycle on the substrate, Includes, The aforementioned process cycle is The steps include: forming a first thin film containing titanium (Ti) by spraying a source containing titanium (Ti) onto the substrate; The steps include: forming a second thin film by spraying a source containing a noble metal element or copper (Cu) onto the substrate; Includes, The step of forming the first thin film is performed multiple times in succession, and the step of forming the second thin film is performed multiple times in succession. The step of forming the first thin film is repeated a greater number of times than the step of forming the second thin film. A method for forming a capacitor electrode, comprising performing the aforementioned process cycle multiple times.

2. The method for forming a capacitor electrode according to claim 1, wherein the step of forming the second thin film is performed before the step of forming the first thin film.

3. A method for forming a capacitor electrode according to claim 1 or 2, wherein the first thin film is formed by a method for depositing a TiN atomic layer.

4. A method for forming a capacitor electrode according to claim 1 or 2, wherein the ratio (T1:T2) of the number of times the step of forming the second thin film is performed (T2) to the number of times the step of forming the first thin film is performed (T1) is adjusted to 1:1 to 10:

1.

5. The method for forming a capacitor electrode according to claim 1 or 2, wherein the source containing the precious metal element is a precursor containing at least one of ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), yttrium (Yi), and molybdenum (Mo).

6. The step of forming the second thin film is: The process involves injecting a source containing a precious metal element or copper (Cu), followed by injecting a reducing gas. A step of activating the reducing gas using plasma, A method for forming a capacitor electrode according to claim 1 or 2, comprising:

7. The step of forming the second thin film is: The process involves injecting a source containing a precious metal element or copper (Cu), followed by injecting a reducing gas. The steps include: exposing the substrate to plasma, A method for forming a capacitor electrode according to claim 1 or 2, comprising:

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