KR101035582B1 - Storage node, capacitor emploing the same and fabrication method therof - Google Patents

Abstract

The present invention is to provide a storage electrode, a capacitor having the same, and a method of manufacturing the same, which can greatly increase the capacitance per unit area while increasing the degree of integration of a semiconductor memory device. A storage node of a capacitor includes a plurality of first electrodes having a second electrode and a second electrode bonded to the first electrodes through an opening of each of the first electrodes.

Capacitor, Cylindrical Storage Node

Description

STORAGE NODE, CAPACITOR EMPLOING THE SAME AND FABRICATION METHOD THEROF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor manufacturing technology, and more particularly, to a cylinder type storage node, a capacitor having the same, and a manufacturing method thereof.

In order to increase the degree of integration of the semiconductor memory device, the size of the memory cell must be reduced. However, when the size of the memory cell is reduced, the capacitance is reduced. When the size of the memory cell is reduced below a certain level, the memory cell does not function as a memory device. Therefore, in order to increase the degree of integration, it is necessary to increase the capacitance per unit area.

Accordingly, the present invention has been proposed to solve the problems according to the prior art, and provides a storage electrode, a capacitor having the same, and a manufacturing method thereof, which can increase capacitance per unit area while increasing the integration degree of a semiconductor memory device. There is a purpose.

According to an aspect of the present invention, a plurality of first electrodes having a plate-like structure and having openings in a central portion thereof, and a plurality of first electrodes penetrating through openings of each of the first electrodes are bonded to the first electrodes. Provided is a storage node of a capacitor comprising two electrodes.

In addition, the present invention according to another aspect for achieving the above object is a storage node of a capacitor including a first electrode having a columnar structure and a plurality of second electrodes bonded to the outer peripheral surface of the first electrode in a projection form To provide.

In addition, the present invention according to another aspect for achieving the above object is a plate formed on the storage node, a dielectric film formed along the profile of the storage node surface, and the dielectric film formed to cover the storage node It provides a capacitor comprising a.

Further, according to another aspect of the present invention, there is provided a method of forming a connection layer on a substrate on which a storage node contact plug is formed, wherein the first electrodes and the first sacrificial layers are formed on the connection layer. Forming a structure stacked alternately with each other, etching the structure to form a storage node pattern hole through which the connection layer is exposed, and forming a second electrode along a step surface of the storage node pattern hole And removing the first sacrificial layer to form a storage node including the connection layer, the first and second electrodes, forming a dielectric layer on a surface along a step of the storage node, and forming the storage node. It provides a method of manufacturing a capacitor comprising forming a plate on the dielectric film to cover.

According to the present invention including the above configuration, by increasing the area of the storage node of the capacitor per unit area, it is possible to obtain high capacitance while improving the high integration of the device.

Hereinafter, with reference to the accompanying drawings, the most preferred embodiment of the present invention will be described.

In the drawings, the thicknesses and spacings of layers (areas) are exaggerated for ease of explanation and clarity, and when referred to as being on another layer or substrate 'top' it may be a different layer or It may be formed directly on the substrate, or a third layer may be interposed therebetween without departing from the technical spirit of the present invention.

In the entire description, when the target layer has an opening, the term 'inner peripheral surface' means a surface around the inner circumference of the opening of the target layer, and the term 'outer peripheral surface' means a surface around an edge of the target layer, that is, an outer surface. . Also, 'round' should be understood to include semicircles, ellipses, and polygons should be understood to include all structures having angles of triangles, squares, pentagons, hexagons, octagons, and the like. Parts denoted by the same reference numerals represent the same layer, and when the reference numerals include English, it means that the same layer is partially deformed through an etching or polishing process.

Example 1

1 is a perspective view illustrating a storage node of a capacitor according to a first embodiment of the present invention.

Referring to FIG. 1, the storage node 119 of the capacitor according to the first embodiment of the present invention has a plate-like structure and has a plurality of first electrodes 111B and 113B having an opening in a central portion thereof, and first electrodes 111B, 113B) a second electrode 117B penetrated through each of the openings and bonded to the first electrodes 111B and 113B.

Each of the first electrodes 111B and 113B has an outer circumferential surface 111-1 and 113-1 having a circular or polygonal structure to increase an area thereof. 1 illustrates a rectangular structure as an example. The first electrodes 111B and 113B are disposed to be spaced apart from each other by a predetermined distance. Although not shown, a plurality of recesses may be formed in the inner circumferential surface of the openings of the first electrodes 111B and 113B.

The second electrode 117B has a columnar structure (bar structure). In addition, the second electrode 117B has a communication structure in which an empty space is formed in the central portion 117-4. In addition, the second electrodes 117B have outer circumferential surfaces 117-2 and 117-3 having a circular or polygonal structure. In FIG. 1, the upper portion of the second electrode 117B is illustrated in a rectangular structure, and the body portion is illustrated in a circular structure. In addition, although not shown, a plurality of recesses may be formed on the outer circumferential surfaces 117-2 and 117-3 to increase the area where the second electrode 117B is bonded to the first electrodes 111B and 113B, respectively. .

In addition, the storage node 119 according to the first embodiment of the present invention may further include an access layer 109A. The connection layer 109A is connected to the lower part of the 2nd electrode 117B. The connection layer 109A is formed of the same material as the first and second electrodes 111B, 113B, and 117B. Preferably, it is formed of a polysilicon film doped with impurity ions. In this case, the impurity ions may be phosphorus (P), boron (B), arsenic (As), or the like.

In addition, the storage node 119 according to the first embodiment of the present invention may further include a bonding layer (not shown) formed between the first and second electrodes 111B, 113B, and 117B. The bonding layer prevents the first electrodes 111B and 113B from falling down from the second electrode 117B. As the bonding layer, any material capable of increasing the bonding property between the first and second electrodes 111B, 113B, and 117B may be used. For example, the bonding layer may include a laminated film (Ti / TiN) in which titanium (Ti) and a titanium nitride film (TiN) are stacked, a laminated film (Ta / TaN) in which tantalum (Ta) and a tantalum nitride film (TaN) are stacked, and tungsten (W). ) And a tungsten nitride film WN are formed as a laminated film W / WN. In addition, it may be formed of a laminated film in which a transition metal and a nitride film thereof (transition metal) are laminated.

Hereinafter, a method of manufacturing a capacitor including the storage node shown in FIG. 1 will be described.

2A through 2J are cross-sectional views illustrating a method of manufacturing a capacitor according to Example 1 of the present invention.

First, as shown in FIG. 2A, a substrate 101 on which a structure is formed is prepared through a series of manufacturing processes. For example, the structure may include a doped region, a junction region, a contact plug, an active element, a passive element, an insulating layer, a conductive layer, and the like. In this case, the contact plug may be formed of any one of a metal film such as aluminum (Al), copper (Cu), tungsten (W), or the like as the conductive layer. In addition, the polycrystalline silicon film doped with impurity ions may be formed.

Next, an insulating film 106 for forming a storage node contact plug pattern is formed to cover the structure. The insulating film 106 is formed in a multilayer insulating film structure. For example, BPSG (BoroPhosphoSilicate Glass) 102, TEOS (Tetra Ethyle Ortho Silicate) 103, nitride film 104, and TEOS 105 are formed as a laminated film sequentially stacked.

Subsequently, as shown in FIG. 2B, the insulating layer 106 (see FIG. 2A) is etched to expose the top surface of the substrate 101 to form a contact hole 107 in which a storage node contact plug is to be formed. Hereinafter, in order to match the reference numerals shown in the drawings, the insulating film is referred to as '106A', the BPSG is '102A', the TEOS is 103A, the nitride film is '104A', and the TEOS is denoted by '105A'.

Subsequently, as illustrated in FIG. 2C, the storage node contact plug in which the contact hole 107 is buried is deposited by depositing a conductive layer (not shown) for the storage node contact plug to fill the contact hole 107. Form 108. The planarization process is performed by an etchback process or a chemical mechanical polishing (CMP) process. At this time, the planarization process is performed by using the nitride film 104A as an etching (or polishing) stop film, so that the TEOS 105A formed on the nitride film 104A is also removed. The conductive film is formed of a transition metal film or a polysilicon film doped with impurity ions.

Next, as shown in FIG. 2D, a connection layer 109 that becomes part of the storage node is formed on the substrate 101 including the nitride film 104A and the storage node contact plug 108. The connection layer 109 is formed of the same material as the storage node contact plug 108. The connection layer 109 is formed by using a furnace equipment or a sheet type chemical vapor deposition (CVD) equipment. The connection layer 109 is formed to a thickness of 300 kPa or more, preferably 300 to 1000 kPa. The connection layer 109 is formed of a polysilicon film, and the source gas during the deposition process, that is, SiH ₄ Together with the gas, a PH ₃ or AsH ₃ gas is injected into the dopant source in an in-situ process to form a doped polycrystalline silicon film.

Next, a structure 115 in which first electrodes 111 and 113 and insulating layers 110, 112 and 114 (hereinafter, referred to as a first sacrificial layer) are alternately stacked on the connection layer 109. do. The number of alternating stacks of the first electrodes 111 and 113 and the first sacrificial layers 110, 112 and 114 in the structure 115 is not limited and may be appropriately adjusted in terms of capacitance. For example, the first electrodes 111 and 113 are formed of a transition metal film. Preferably, it is formed of a polycrystalline silicon film. More preferably, a polycrystalline silicon film doped with impurity ions is formed. The first sacrificial layers 110, 112, and 114 have an etching selectivity with the first electrodes 111 and 113 in a subsequent removal process, and are formed of a material that is easily removable by the etching solution. Preferably, it is formed of an oxide film. More preferably, it is formed of TEOS.

Subsequently, as illustrated in FIG. 2E, the structure 115 (see FIG. 2D) is etched to form a storage node pattern hole 116 on which the storage node is to be formed. In this case, the etching process is performed by a dry etching process, so that the connection layer 109 is exposed. The storage node pattern hole 116 may be formed in a circular or polygonal shape according to the shape of a mask used in an etching process, and is formed in an area facing the storage node contact plug 108. Hereinafter, in order to match the reference numerals shown in the drawings, the structures are denoted by '115A', the first electrodes are denoted by '111A' and '113A', and the first sacrificial layers are denoted by '110A', '112A', and '114A'. '

Subsequently, although not shown, a wet etching process may be further performed to form a plurality of recesses on the outer circumferential surface of the second electrode 117 formed in FIG. 2F. In this case, the wet etching process is performed so that the first sacrificial layers 110A, 112A, and 114A are partially etched to form recesses between the first electrodes 111A and 113A. This recessed portion forms a plurality of recesses such as bends on the outer circumferential surface of the second electrode 117 during the subsequent process of forming the second electrode 117. As such, the wet etching process uses an etching solution including hydrofluoric acid (HF) to selectively etch only TEOS to form recesses in the first sacrificial layers 110A, 112A, and 114A.

Next, as shown in FIG. 2F, a second electrode 117 is formed on the structure 115A including the storage node pattern hole 116 along the step surface of the storage node pattern hole 116 (see FIG. 2E). do. The second electrode 117 is formed along the outer surface of the structure 115A including the storage node pattern hole 116. The second electrode 117 is formed of the same material as the first electrodes 111A and 113A. For example, it is formed of a transition metal film. Preferably, it is formed of a polycrystalline silicon film. More preferably, a polycrystalline silicon film doped with impurity ions is formed.

Meanwhile, before forming the second electrode 117, a bonding layer (not shown) may be formed along the stepped surface of the storage node pattern hole 116. The bonding layer increases the adhesive force between the first electrodes 111A and 113A and the second electrode 117, and thus, the first electrodes 111A and 113A during the subsequent removal of the second sacrificial layers 110A, 112A and 114A. 113A) can be prevented from falling or collapsing. It is preferable to form a joining layer with Ti / TiN, Ta / TaN, and W / WN.

Next, an insulating layer 118 (hereinafter, referred to as a second sacrificial layer) is formed on the second electrode 117 to fill the storage node pattern hole 116. The second sacrificial layer 118 is formed of the same material as the first sacrificial layers 110A, 112A, and 114A so that the second sacrificial layers 118 may be removed together during the subsequent removal process of the first sacrificial layers 110A, 112A, and 114A. For example, it is formed of an oxide film. It is preferably formed of TEOS.

Subsequently, as shown in FIG. 2G, the second sacrificial layer 118 (see FIG. 2F), the second electrode 117 (see FIG. 2F), the structure 115A (see FIG. 2F), and the connection layer 109, FIG. 2F are referred to. ) Are sequentially etched to form a target pattern. In this case, the etching process is performed by a dry etching process, and is performed until the nitride film 104A is exposed. That is, the nitride film 104A is used as the etch stop film. Hereinafter, the second sacrificial layer is '118A', the second electrode is '117A', the first electrodes are '111B', '113B', and the first sacrificial layer is '110B', '112B' to match the reference numerals shown in the drawings. , Denoted '114B'.

In FIG. 2G, the storage node may be implemented in various structures according to a mask shape used in an etching process. In particular, the first electrodes 111B and 113B and the second electrode 117A having a large influence on the capacitance may be formed in various structures according to a mask shape. According to the mask shape, the first electrodes 111B and 113B may have a plate-like structure surrounding the outer circumferential surface of the second electrode 117A or a protrusion such as a fin protruding from the outer circumferential surface of the second electrode 117A. It may be. In addition, a recess may be formed on the edge circumferential surface, that is, the outer circumferential surface of the first electrodes 111B and 113B according to the mask shape. In addition, an upper portion of the second electrode 117A, in particular, facing the first electrodes 111B and 113B may be formed in the same structure as the first electrodes 111B and 113B. As such, various structures capable of increasing the area according to the mask shape are possible.

Subsequently, as shown in FIG. 2H, the second sacrificial layer 118A (see FIG. 2G) and the first sacrificial layers 110B, 112B, 114B and FIG. 2G are removed by etching. At this time, the etching process is performed by a wet etching process. The wet etching process is formed of an etching solution having a high etching selectivity between the oxide film and the polycrystalline silicon film. Preferably it is carried out using a solution of any one of BOE (Buffered Oxide Etch), BHF (Buffered HF) or DHF (Diluted HF) solution. As a result, the storage node 119 (see FIG. 1) having the first electrodes 111B and 113B bonded to the outer circumferential surface of the second electrode 117A is formed, and the storage node 119 is formed under the second electrode 117A. It includes the connection layer 109A bonded to it.

Subsequently, as shown in FIG. 2I, the dielectric film 120 is formed along the stepped surface of the substrate 101 including the first electrodes 111B and 113B, the second electrode 119, and the connection layer 109A. Form. The dielectric film 120 is formed of an oxide film or a laminated film (eg, an oxide film / nitride film / oxide film) in which an oxide film and a nitride film are alternately stacked. Further, it is formed of a metal oxide film having a high dielectric constant. The metal oxide film is a material having a dielectric constant of 3.9 or more, for example, an aluminum oxide film (Al ₂ O ₃ ), a hafnium oxide film (HfO ₂ ), a zirconium oxide film (ZrO ₂ ), a tantalum oxide film (Ta ₂ O ₅ ) or a mixed film thereof. Or a lamination film in which these are laminated sequentially.

Subsequently, as illustrated in FIG. 2J, a plate 121 is formed on the dielectric film 120 to cover the first electrodes 111B and 113B, the second electrode 117A, and the connection layer 109A. The plate 120 is formed of the same material as the storage node including the first electrodes 111B and 113B, the second electrode 117A, and the connection layer 109A. For example, it is formed of a transition metal film or a polycrystalline silicon film. Preferably, it is formed of a polysilicon film doped with impurity ions.

Subsequently, in order to finally form a desired profile, the plate 121, the dielectric film 120, and the connection layer 109A may be etched to implement the same profile as in FIG.

Example 2

3 is a perspective view illustrating a storage node of a capacitor according to Embodiment 2 of the present invention.

Referring to FIG. 3, the storage node 219 according to the second exemplary embodiment of the present invention has a protrusion on a first electrode 217 having a columnar structure and an outer circumferential surface 217-2 of the first electrode 217. A plurality of bonded second electrode 213 is included.

The first electrode 217 has a columnar structure (bar structure). In addition, the first electrode 217 has a communication structure in which an empty space is formed in the central portion 217-3. In addition, the first electrode 217 has an outer circumferential surface 217-2 having a circular or polygonal structure. In FIG. 3, for example, an upper portion of the first electrode 217 is illustrated as having a propeller-shaped protrusion, and a body is illustrated as a circular structure. At this time, the number of protrusions is not limited, and is patterned at the same time as the second electrodes 213, so that they are formed in the same number and shape. For example, the protrusions may be formed one each in the east, west, north and south directions, or one each in the east, west, or north and south. In addition, although not shown, a plurality of recesses may be formed on the outer circumferential surface 217-2 to increase the area of the first electrode 217 that is bonded to the plate (not shown).

The second electrodes 213 are formed in a protrusion structure on the outer circumferential surface of the first electrode 217 to increase the area. The second electrodes 213 are patterned at the same time as the protrusion formed on the first electrode 217 to have the same structure. The number is also not limited. The second electrodes 213 have an outer circumferential surface having a circular or polygonal structure. 3 illustrates a rectangular structure as an example. The first electrodes 217 are arranged to be spaced apart from each other by a predetermined distance.

In addition, the storage node 219 according to the second embodiment of the present invention may further include an access layer 209. A portion of the connection layer 209 is connected to a lower portion of the first electrode 217, and a portion of the connection layer 209 protruding to the outside of the first electrode 217 has the same structure as the second electrodes 213. Since the connection layer 209 functions as a storage node together with the first and second electrodes 217 and 213, the connection layer 209 is formed of the same material. Preferably, it is formed of a polysilicon film doped with impurity ions. In this case, the impurity ions may be phosphorus (P), boron (B), arsenic (As), or the like.

In addition, the storage node 219 according to the second embodiment of the present invention may further include a bonding layer (not shown) formed between the first and second electrodes 217 and 213. The bonding layer prevents the second electrodes 213 from falling down from the first electrode 217. As the bonding layer, any material capable of increasing bonding characteristics between the first and second electrodes 217 and 213 may be used.

The method of manufacturing the capacitor including the storage node according to the second embodiment of the present invention may proceed in the same manner as the method of manufacturing the capacitor according to the first embodiment. However, the etching process performed in FIG. 2G may be implemented by using a mask having a different form from that in Example 1. FIG. For example, the mask form may use a propeller form.

As described above, although the technical spirit of the present invention has been described in detail in the preferred embodiments, it should be noted that the above-described embodiments are for the purpose of description and not of limitation. As such, those skilled in the art may understand that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a perspective view showing a storage node of a capacitor according to the first embodiment of the present invention.

2A to 2J are cross-sectional views illustrating a method of manufacturing a capacitor including the storage node according to the first embodiment of the present invention.

3 is a perspective view showing a storage node of a capacitor according to Embodiment 2 of the present invention;

<Explanation of symbols for the main parts of the drawings>

101: substrate

102, 102A: BPSG

103, 103A, 105, 105A, 110, 110A, 110B, 112, 112A, 112B, 114, 114A, 114B, 118, 118A: TEOS

104, 104A: nitride film

106, 106A: insulating film

107: contact hole

108: storage node contact plug

109, 109A, 209: connection layer

111, 111A, 111B, 113, 113A, 113B, 217: first electrode

116: storage node pattern holes

117, 117A, 213: second electrode

120: dielectric film

121: plate

Claims (32)

A plurality of first electrodes forming a plate-like structure and having an opening in a central portion thereof; A second electrode connected to the first electrodes through the opening of each of the first electrodes; And And a connection layer formed below the second electrode. The connection layer is connected to one region of the second electrode, the storage node of the capacitor. The method of claim 1, The storage node of the capacitor further comprises a bonding layer for bonding the first electrode and the second electrode. The method of claim 2, The junction layer is a storage node of a capacitor formed of any one selected from Ti / TiN, Ta / TaN or W / WN. The method of claim 1, The opening is a storage node of a capacitor having a plurality of recesses formed on the inner circumferential surface. The method of claim 1, The second electrode is a storage node of a capacitor formed in a columnar shape having an upper plate-like structure. The method of claim 1, The second electrode is a storage node of a capacitor having a plurality of recesses formed on the outer peripheral surface. The method of claim 1, The storage node of the capacitor, wherein the first electrode and the second electrode are formed of the same material. The method of claim 1, The second electrode is a storage node of a capacitor having a communication structure in which an empty space is formed in the center. delete The method of claim 1, The connection layer is a storage node of a capacitor formed of the same material as the first electrode and the second electrode. The method of claim 1, The connection layer is a storage node of a capacitor formed of a polysilicon film doped with impurity ions. The method of claim 1, The first electrode is a storage node of a capacitor formed adjacent to each other. A first electrode having a columnar structure; A plurality of second electrodes joined to an outer circumferential surface of the first electrode in a protrusion shape; And And a connection layer formed below the first electrode. The connection layer is connected to one region of the first electrode storage node of a capacitor. The method of claim 13, The storage node of the capacitor further comprises a bonding layer for bonding the first electrode and the second electrode. The method of claim 14, The junction layer is a storage node of a capacitor formed of any one selected from Ti / TiN, Ta / TaN or W / WN. The method of claim 13, The first electrode is a storage node of a capacitor having a plurality of protrusions integrally formed thereon. The method of claim 13, The storage node of the capacitor, wherein the first electrode and the second electrode are formed of the same material. The method of claim 13, The first electrode is a storage node of a capacitor having a communication structure in which an empty space is formed in the center. delete The method of claim 13, The connection layer is a storage node of a capacitor formed of the same material as the first electrode and the second electrode. The method of claim 13, The connection layer is a storage node of a capacitor formed of a polysilicon film doped with impurity ions. The method of claim 13, The first electrode is a storage node of a capacitor formed adjacent to each other. 23. A storage node as claimed in any one of claims 1 to 8, 10 to 18 and 20 to 22; A dielectric film formed along the profile of the storage node surface; And A plate formed on the dielectric layer formed to cover the storage node Capacitor comprising a. Forming a connection layer on the substrate on which the storage node contact plug is formed; Forming a structure in which first electrodes and first sacrificial layers are alternately stacked on each other on the connection layer; Etching the structure to form a storage node pattern hole through which the connection layer is exposed; Forming a second electrode along a step surface of the storage node pattern hole; Removing the first sacrificial layer to form a storage node including the connection layer, the first and second electrodes; Forming a dielectric film on a surface along the step of the storage node; And Forming a plate on the dielectric layer to cover the storage node; And the connection layer is connected to one region of the second electrode. The method of claim 24, Before forming the second electrode, And forming a bonding layer along the stepped surface of the storage node pattern hole. The method of claim 25, The bonding layer is a manufacturing method of a capacitor formed of any one selected from Ti / TiN, Ta / TaN or W / WN. The method of claim 25, And the connection layer is formed of a polysilicon film doped with impurity ions. The method of claim 24, The second electrode is a capacitor manufacturing method of forming a columnar upper portion having a plate-like structure. The method of claim 24, The first electrode and the second electrode is a capacitor manufacturing method of forming the same material with each other. The method of claim 24, And the connection layer is formed of the same material as the first electrode and the second electrode. The method of claim 24, And the connection layer is formed of a polysilicon film doped with impurity ions. The method of claim 24, After forming the second electrode, And etching the structure and the second electrode to pattern the protrusion on the outer circumferential surface of the second electrode so that the structure remains.

Images