Contact structure and semiconductor memory device including the same

Abstract

The present invention provides a contact structure having improved electrical characteristics and a semiconductor memory device including the same. [Solution] The contact structure according to the present invention comprises a contact insulating layer defining a preliminary contact hole, a first insulating spacer extending along the side surface of the preliminary contact hole, a second insulating spacer provided on the upper side surface of the first insulating spacer, and a contact filling the contact hole defined by the first insulating spacer and the second insulating spacer, wherein each of the contacts provided on the bottom surface of the second insulating spacer and the contacts provided on the side surface of the second insulating spacer has a width that increases along the direction from the bottom surface to the top surface of the contact, and the maximum width of the contact provided on the bottom surface of the second insulating spacer is greater than the minimum width of the contact provided on the side surface of the second insulating spacer.

Description

Technical Field

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[0001] The present invention relates to a contact structure and a semiconductor memory device including the same, and more particularly, to a contact structure having improved electrical characteristics and a semiconductor memory device including the same.

Background Art

[0002] In response to the trend of miniaturization and thinning of electronic products, the demand for high integration of memory devices is increasing. A cross-point memory device has a structure in which an upper electrode and a lower electrode intersect vertically, and memory cells are arranged in the intersecting regions. Such a structure has the advantage of having small memory cells on a plane. Generally, a memory cell of a cross-point memory device includes a two-terminal selector and a memory element connected in series with each other to prevent sneak current between adjacent memory cells.

[0003] However, this causes a problem that the aspect ratio of a unit memory cell becomes large, the manufacturing process of the memory cell is complicated, and there is a limit to increasing the memory capacity of the memory device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the problems in the above conventional memory devices, and an object of the present invention is to provide a contact structure having improved electrical characteristics and a semiconductor memory device including the same. [Means for solving the problem]

[0006] To achieve the above objective, the contact structure according to the present invention comprises: a contact insulating layer defining a preliminary contact hole; a first insulating spacer extending along the side surface of the preliminary contact hole; a second insulating spacer provided on the upper side surface of the first insulating spacer; and a contact filling the contact hole defined by the first insulating spacer and the second insulating spacer, wherein each of the contacts provided on the bottom surface of the second insulating spacer and the contacts provided on the side surface of the second insulating spacer has a width that increases along the direction from the bottom surface to the top surface of the contact, and the maximum width of the contact provided on the bottom surface of the second insulating spacer is greater than the minimum width of the contact provided on the side surface of the second insulating spacer.

[0007] Furthermore, a contact structure according to the present invention made to achieve the above objective comprises a first conductive line extending in a first direction, a second conductive line extending in a second direction intersecting the first direction on the first conductive line, and a contact provided between the first conductive line and the second conductive line, wherein the contact includes a first portion adjacent to the first conductive line and a second portion adjacent to the second conductive line, and each of the first and second portions has a width that increases as it moves along the direction from the first conductive line toward the second conductive line, and the maximum width of the first portion is greater than the minimum width of the second portion.

[0008] To achieve the above objective, the semiconductor memory device according to the present invention comprises: a word line extending in a first direction; a bit line extending in a second direction intersecting the first direction on the word line and spaced away from the word line along a third direction perpendicular to the first and second directions; a selector-only memory element provided between the word line and the bit line; and a plurality of contacts electrically connected to the word line and the bit line, respectively, wherein each of the plurality of contacts includes a first portion relatively far from the word line or the bit line and a second portion relatively close to the word line or the bit line, and each of the first portion and the second portion has a width that increases as it goes along the third direction, and the maximum width of the first portion is greater than the minimum width of the second portion. [Effects of the Invention]

[0009] According to the contact structure and semiconductor memory device including the same according to the present invention, the contact has an upper part having a small width and a lower part having a large width, and the contact is electrically connected to a word line or bit line at the upper part. A small upper contact width can reduce or substantially prevent unwanted electrical influence from adjacent word lines or bit lines, while a large lower contact width can increase the contact area in contact with the external conductive line, thus allowing the contact to easily connect electrically with the external conductive line. Therefore, it is possible to provide contact structures and semiconductor memory devices with improved electrical characteristics. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the schematic configuration of a semiconductor memory device according to an embodiment of the present invention. [Figure 2] This is a partial cross-sectional view showing the schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 3] A flowchart for explaining a method of manufacturing a contact structure according to an embodiment of the present invention. [Figure 4] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 5] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 6] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 7] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 8] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 9] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 10] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 11] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 12] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 13] A partial cross-sectional view for explaining the method of manufacturing the contact structure of FIG. 3. [Figure 14] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 15] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 16] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 17] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 18] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. <00OO090> [Figure 19]A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 20] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 21] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention. [Figure 22] A partial cross-sectional view showing a schematic configuration of a contact structure according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0011] Next, specific examples of embodiments for implementing a contact structure according to the present invention and a semiconductor memory device including the same will be described with reference to the drawings.

[0012] As used herein, the term "at least one of" refers to and includes all possible combinations of one or more of the associated listed terms. For example, the term "at least one of A, B, or C" means (i) at least one of A, (ii) at least one of B, (iii) at least one of C, (iv) at least one of A and at least one of B, (v) at least one of B and at least one of C, (vi) at least one of A and at least one of C, or (vii) at least one of A, at least one of B, and at least one of C, where A, B, and C can be singular or plural.

[0013] FIG. 1 is a perspective view showing a schematic configuration of a semiconductor memory device according to an embodiment of the present invention. Referring to FIG. 1, a memory device 10 including a word line WL, a bit line BL, and a selector-only memory element SOM is provided.

[0014] The word line WL extends along the first direction DR1. Word line WL is arranged along the second direction DR2. Wordline WL contains conductive material. For example, the wordline WL may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0015] The bit line BL intersects with the word line WL. The bit line BL is extended along the second direction DR2. The bit line BL is arranged along the first direction DR1. In contrast, the word line WL can also be arranged along the second direction DR2. Bitline BL contains a conductive material. For example, bit line BL may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0016] A selector-only memory element (SOM) is provided between the word line (WL) and the bit line (BL). The selector-only memory element (SOM) is positioned in the region where the word line (WL) and the bit line (BL) intersect. Each selector-only memory element (SOM) includes a lower electrode BE, a memory layer ML, and an upper electrode UE, all arranged along a third direction DR3. The lower electrode BE is electrically connected to the word line WL. For example, the lower electrode BE is in contact with the word line WL. The lower electrode BE contains a conductive material. For example, the lower electrode BE may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0017] The upper electrode UE is electrically connected to the bit line BL. For example, the upper electrode UE is in contact with the bit line BL. The upper electrode UE contains a conductive material. For example, the upper electrode UE may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0018] The memory layer ML exhibits ovonic threshold switching (OTS) characteristics, having a high resistance state when a voltage lower than the threshold voltage (e.g., an even lower absolute value voltage) is applied, and a low resistance state when a voltage higher than the threshold voltage (e.g., an even higher absolute value voltage) is applied. The memory layer ML has memory characteristics in which the threshold voltage is shifted depending on the polarity and strength of the applied bias voltage. Therefore, the memory layer ML has the characteristics of a self-selecting memory that can perform all memory and selector functions. In one embodiment, the memory layer ML contains a single substance of a multi-component chalcogenide. For example, the memory layer ML may be a single layer comprising at least one material from among GeAsSe, GeAsSeIn, GeAsSeSIn, GeAsSeSb, GeAsSeSbIn, GeAsSeTe, GeAsSeTeIn, GeAsSeAl, GeAsSeAlIn, GeSbSe, GeSbSeIn, GeSbSeN, and GeSbSeNIn. For example, the memory layer ML includes a single layer such as GeAsSe doped with indium (In). For example, the memory layer ML may include at least one material from among GeAsSeIn, GeAsSeIn, and GeAsSeAlIn.

[0019] For example, if the memory layer ML contains indium (In) doped or bonded at an atomic concentration of approximately 10%, off-current leakage may increase. However, it has been experimentally confirmed that the resistance and threshold voltage drift characteristics of such indium-based elements are greatly improved, and that the threshold voltage shift can be maintained at a similar value. Furthermore, in one embodiment, silicon (Si) does not need to be present within the memory layer ML. For example, if the memory layer ML does not contain silicon (Si), leakage current can be reduced and leakage current characteristics can be improved.

[0020] The word line WL and bit line BL are electrically connected to the external conductive lines through contacts. The external lines are configured to provide signals to store data in the memory layer ML via the word line WL and bit line BL, or to allow data to be read from the memory layer ML. In one embodiment, the contact is configured to connect to at least one of the ends of the corresponding bit line BL along the second direction DR2 and at least one of the ends of the corresponding word line WL along the first direction DR1. For example, the contacts are in contact with the bottom surface of the bit line BL and the bottom surface of the word line WL. For example, the external conductive line is provided at a lower level than the word line WL. The bit line BL and word line WL correspond to the second conductive line (reference numeral 180 in Figure 2), which will be described later. The external conductive line corresponds to the first conductive line (reference numeral 120 in Figure 2), which will be described later. The following describes contacts configured to electrically connect a word line WL or a bit line BL to an external conductive line.

[0021] Figure 2 is a partial cross-sectional view showing the schematic configuration of a contact structure according to an embodiment of the present invention. Referring to Figure 2, a wiring insulation layer 110 is provided. The wiring insulation layer 110 contains an electrical insulating material. For example, the wiring insulation layer 110 may contain at least one of SiO2, Al2O3, and HfO2.

[0022] A first conductive line 120 is embedded on top of the wiring insulation layer 110. In one embodiment, the first conductive line 120 is an external conductive line. The first conductive line 120 is extended along the second direction DR2. The first conductive line 120 contains a conductive material. For example, the first conductive line 120 may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0023] A contact insulating layer 130 is provided on the wiring insulating layer 110 and the first conductive line 120. The contact insulating layer 130 contains an electrical insulating material. For example, the contact insulating layer 130 may contain at least one of SiO2, Al2O3, and HfO2. In one embodiment, the wiring insulation layer 110 and the contact insulation layer 130 are connected to each other without an interface between them. In one embodiment, an interface is provided between the wiring insulation layer 110 and the contact insulation layer 130.

[0024] The contact insulating layer 130 includes a spare contact hole 132. The spare contact hole 132 extends along the third direction DR3. The spare contact hole 132 penetrates the contact insulating layer 130. The spare contact hole 132 exposes the first conductive line 120. The contact insulating layer 130 adjacent to the spare contact hole 132 covers the first conductive line 120. A first insulating spacer 142 is provided on the side surface of the contact insulating layer 130 exposed by the pre-contact hole 132. The first insulating spacer 142 fills a portion of the spare contact hole 132. For example, the first insulating spacer 142 extends along the side surface of the contact insulating layer 130 exposed by the preliminary contact hole 132. The lower part of the first insulating spacer 142 is in contact with the first conductive line 120. The upper surface of the first insulating spacer 142 is at substantially the same height as the upper surface of the contact insulating layer 130. For example, the upper surface of the contact insulating layer 130 and the upper surface of the first insulating spacer 142 are substantially coplane. The first insulating spacer 142 contains an electrical insulating material. For example, the first insulating spacer 142 may contain at least one of SiO2, Al2O3, and HfO2. An interface is formed between the first insulating spacer 142 and the contact insulating layer 130.

[0025] A second insulating spacer 162 is provided on the side surface of the first insulating spacer 142 facing inward towards the spare contact hole 132. The second insulating spacer 162 fills the remaining portion of the spare contact hole 132. The remaining portion of the spare contact hole 132 is referred to as contact hole CTH. The second insulating spacer 162 is provided on top of the first insulating spacer 142. The upper surface of the second insulating spacer 162 is located at substantially the same height as the upper surface of the first insulating spacer 142. For example, the upper surface of the second insulating spacer 162 and the upper surface of the first insulating spacer 142 are substantially on the same plane. The lower part of the second insulating spacer 162 is separated from the first conductive line 120. The lower side surface of the first insulating spacer 142 is exposed on the bottom surface of the second insulating spacer 162. In other words, the second insulating spacer 162 is not provided on the lower side surface of the first insulating spacer 142. The second insulating spacer 162 contains an electrical insulating material. For example, the second insulating spacer 162 may contain at least one of SiO2, Al2O3, and HfO2. An interface is formed between the first insulating spacer 142 and the second insulating spacer 162.

[0026] Contact 172 is provided in contact hole CTH. Contact 172 fills the contact hole CTH. Contact 172 is electrically connected to the first conductive line 120. For example, contact 172 is in direct contact with the first conductive line 120. Contact 172 contains a conductive material. For example, contact 172 may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs). The contact 172 is in contact with the side and bottom surfaces of the second insulating spacer 162. Contact 172 is in contact with the side surface of the first insulating spacer 142, which is exposed on the bottom surface of the second insulating spacer 162.

[0027] The contact 172 has a width that increases as it goes along the third direction DR3, then narrows, and then increases again. For example, the width of contact 172 is the size of contact 172 along the first direction DR1. The width of the contact 172 provided between the second insulating spacer 162 and the first conductive line 120 increases as it goes along the third direction DR3. The width of the contact 172 provided on the side surface of the second insulating spacer 162 increases as it goes along the third direction DR3. The maximum width of the contact 172 provided between the second insulating spacer 162 and the first conductive line 120 is greater than the maximum width of the contact 172 provided on the side surface of the second insulating spacer 162. In one embodiment, the minimum width of the contact 172 provided between the second insulating spacer 162 and the first conductive line 120 is greater than the maximum width of the contact 172 provided on the side surface of the second insulating spacer 162.

[0028] A second conductive line 180 is provided on the contact 172. In one embodiment, the second conductive line 180 is a word line WL or a bit line BL. Exemplary, the second conductive line 180 is illustrated by a word line WL extending along the first direction DR1. If the second conductive line 180 is bit line BL, the second conductive line 180 is extended along the second direction DR2. The second conductive line 180 is electrically connected to the contact 172. For example, the second conductive line 180 is in direct contact with the contact 172. The second conductive line 180 contains a conductive material. For example, the second conductive line 180 may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0029] The contact 172 of the present invention has an upper part having a small width and a lower part having a large width. Contact 172 is electrically connected to a word line or bit line at the top. The small upper width of contact 172 can reduce or substantially prevent unwanted electrical influence from adjacent word lines or adjacent bit lines. The large lower width of contact 172 increases the surface area of ​​contact 172 that comes into contact with the external conductive line. Therefore, contact 172 can be easily electrically connected to an external conductive line. Therefore, a contact structure CS1 and a semiconductor memory device 10 with improved electrical characteristics are provided.

[0030] Figure 3 is a flowchart illustrating a method for manufacturing a contact structure according to an embodiment of the present invention, and Figures 4 to 13 are partial cross-sectional views illustrating the method for manufacturing the contact structure shown in Figure 3.

[0031] Referring to Figures 3 and 4, a contact insulation layer 130 including a preliminary contact hole 132 is formed on the wiring insulation layer 110 in which the first conductive line 120 is embedded (step S110). Embedding the first conductive line 120 in the wiring insulation layer 110 includes forming a portion of the wiring insulation layer 110, forming the first conductive line 120 extending along the second direction DR2 on the portion of the wiring insulation layer 110, and forming another portion of the wiring insulation layer 110 on the side surface of the first conductive line 120. For example, forming part and other parts of the wiring insulation layer 110 is carried out by a chemical vapor deposition process or a physical vapor deposition process. The wiring insulation layer 110 contains an electrical insulating material. For example, the wiring insulation layer 110 may contain at least one of SiO2, Al2O3, and HfO2.

[0032] Forming the first conductive line 120 includes, for example, forming a conductive film on the portion of the wiring insulating layer 110 and patterning the conductive film. For example, the formation of a conductive film is carried out by a chemical vapor deposition process or a physical vapor deposition process. The conductive film contains a conductive substance. For example, the conductive film may contain at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs). For example, a conductive film is patterned by a dry etching process or a wet etching process that utilizes an etching mask provided on the conductive film.

[0033] Forming the contact insulating layer 130, which includes the preliminary contact holes 132, involves forming the contact insulating layer 130 on the wiring insulating layer 110 and the first conductive line 120, and patterning the contact insulating layer 130. For example, the contact insulating layer 130 is formed by a chemical vapor deposition process or a physical vapor deposition process. The contact insulating layer 130 contains an electrical insulating material. For example, the contact insulating layer 130 may contain at least one of SiO2, Al2O3, and HfO2. In one embodiment, the wiring insulation layer 110 and the contact insulation layer 130 are connected to each other without an interface between them. In one embodiment, an interface is provided between the wiring insulation layer 110 and the contact insulation layer 130. For example, the contact insulating layer 130 is patterned by a dry etching process or a wet etching process using an etching mask provided on the contact insulating layer 130. Patterning the contact insulating layer 130 is carried out until the first conductive line 120 is exposed.

[0034] Referring to Figures 3 and 5, a first insulating spacer film 140 is formed in the preliminary contact hole 132 (step S120). The first insulating spacer film 140 extends along the sides and bottom of the contact hole CTH. The first insulating spacer film 140 is provided on the side surface of the contact insulating layer 130 exposed by the preliminary contact hole 132 and on the upper surface of the first conductive line 120. The first insulating spacer film 140 is provided on the upper surface of the contact insulating layer 130. The first insulating spacer film 140 contains an electrical insulating material. For example, the first insulating spacer film 140 may contain at least one of SiO2, Al2O3, and HfO2.

[0035] Referring to Figures 3 and 6, a portion of the first insulating spacer film 140 is removed to form the first insulating spacer 142 (step S130). Removing a portion of the first insulating spacer film 140 includes, for example, an etch-back process on the first insulating spacer film 140. The etch-back process is carried out until the upper surface of the contact insulating layer 130 and the upper surface of the first conductive line 120 are exposed. A first insulating spacer 142 is provided on the side surface of the contact insulating layer 130 exposed by the pre-contact hole 132. The first insulating spacer 142 fills a portion of the spare contact hole 132. The upper surface of the first insulating spacer 142 is positioned at substantially the same height as the upper surface of the contact insulating layer. For example, the upper surface of the contact insulating layer 130 and the upper surface of the first insulating spacer 142 are substantially coplane.

[0036] Referring to Figures 3 and 7, a mold film 150 is formed to fill the remaining portion of the preliminary contact hole 132 (step S140). The molded film 150 is further provided on the upper surface of the contact insulating layer 130, covering the upper surface of the contact insulating layer 130. For example, the molded film 150 includes a spin-on hard mask. For example, forming the molded film 150 includes spin-coating a spin-on hard mask onto the contact insulating layer 130 and curing the spin-on hard mask.

[0037] Referring to Figures 3 and 8, the upper part of the mold film 150 is removed to form the mold pattern 152 (step S150). For example, removing the top layer of the molded film 150 involves an ashing process utilizing oxygen plasma. The mold pattern 152 is provided below the preliminary contact hole 132. The mold pattern 152 is in contact with the upper surface of the first conductive line 120 and the side surface of the first insulating spacer 142 adjacent to the first conductive line 120. The upper part of the molded film 150 is removed to expose the upper side surface of the first insulating spacer 142.

[0038] Referring to Figures 3 and 9, a second insulating spacer film 160 is formed in the preliminary contact hole 132 (step S160). The second insulating spacer film 160 extends along the sides and bottom of the preliminary contact hole 132 in which the first insulating spacer 142 and mold pattern 152 are formed. The second insulating spacer film 160 is provided on the side surface of the first insulating spacer 142 and on the upper surface of the mold pattern 152. The second insulating spacer film 160 is provided on the upper surface of the first insulating spacer 142 and the upper surface of the contact insulating layer 130. The second insulating spacer film 160 contains an electrical insulating material. For example, the second insulating spacer film 160 may contain at least one of SiO2, Al2O3, and HfO2.

[0039] Referring to Figures 3 and 10, a portion of the second insulating spacer film 160 is removed to form the second insulating spacer 162 (step S170). Removing a portion of the second insulating spacer film 160 includes, for example, an etch-back process on the second insulating spacer film 160. The etch-back process is carried out until the upper surface of the contact insulating layer 130 and the upper surface of the mold pattern 152 are exposed. The second insulating spacer 162 is formed on the side surface of the first insulating spacer 142. The second insulating spacer 162 fills the remaining portion of the spare contact hole 132. The upper surface of the second insulating spacer 162 is located at substantially the same height as the upper surface of the first insulating spacer 142. For example, the upper surface of the second insulating spacer 162 and the upper surface of the first insulating spacer 142 are substantially on the same plane.

[0040] Referring to Figures 3 and 11, the mold pattern 152 is removed to form the contact hole CTH (step S180). For example, removing the mold pattern 152 involves an ashing process utilizing oxygen plasma. The contact hole CTH is the area between the first insulating spacer 142 and the second insulating spacer 162 in the spare contact hole 132. The contact hole CTH exposes the bottom surface of the second insulating spacer 162, the lower side surface of the first insulating spacer 142 on the bottom surface of the second insulating spacer 162, and the upper surface of the first conductive line 120.

[0041] The contact hole CTH has a width that increases as you go along the third direction DR3, then narrows, and then increases again. For example, the width of the contact hole CTH is the size of the contact hole CTH along the first direction DR1. The width of the contact hole CTH provided between the second insulating spacer 162 and the first conductive line 120 increases as it goes along the third direction DR3. The width of the contact hole CTH provided on the side surface of the second insulating spacer 162 increases as it goes along the third direction DR3. The maximum width of the contact hole CTH provided between the second insulating spacer 162 and the first conductive line 120 is greater than the maximum width of the contact hole CTH provided on the side surface of the second insulating spacer 162.

[0042] Referring to Figures 3 and 12, a preliminary contact film 170 is formed to fill the contact hole CTH (step S190). The preliminary contact film 170 is further provided on the upper surface of the contact insulating layer 130, covering the upper surface of the contact insulating layer 130. For example, the preliminary contact film 170 contains a conductive material. For example, contact 172 may include at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs).

[0043] Referring to Figures 3 and 13, a portion of the preliminary contact film 170 is removed to form the contact 172 (step S200). Removing a portion of the preliminary contact film 170 includes, for example, an etch-back process on the preliminary contact film 170. The etch-back process is carried out until the upper surface of the contact insulating layer 130, the upper surface of the first insulating spacer 142, and the upper surface of the second insulating spacer 162 are exposed. Contact 172 fills the contact hole CTH. The upper surface of contact 172 is positioned at substantially the same height as the upper surface of the second insulating spacer 162. For example, the upper surface of contact 172 and the upper surface of second insulating spacer 162 are substantially coplane.

[0044] Referring to Figures 3 and 2, a second conductive line 180 is formed on the contact 172 (step S210). Forming the second conductive line 180 includes, for example, forming a conductive film on the contact insulating layer 130 and patterning the conductive film. For example, the formation of a conductive film is carried out by a chemical vapor deposition process or a physical vapor deposition process. The conductive film contains a conductive substance. For example, the conductive film may contain at least one of the following: metals (e.g., titanium (Ti), titanium nitride (TiN), tungsten (W), platinum (Pt), tantalum nitride (TaN), aluminum (Al)) and doped semiconductor materials (e.g., doped Si, doped IGZO, doped GaAs). For example, a conductive film is patterned by a dry etching process or a wet etching process that utilizes etching squeegee provided on the conductive film.

[0045] Figure 14 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 14, the contact structure CS2 is provided. Contrary to what was explained with reference to Figure 2, the first insulating spacer 142 and the second insulating spacer 162 constitute a single film. The first insulating spacer 142 and the second insulating spacer 162 are connected to each other without a boundary surface between them. For example, the first insulating spacer 142 and the second insulating spacer 162 contain substantially the same material. For the sake of simplicity, the absence of a boundary surface between the first insulating spacer 142 and the second insulating spacer 162 is represented by a dotted line between the first insulating spacer 142 and the second insulating spacer 162. An interface is formed between the first insulating spacer 142 and the contact insulating layer 130.

[0046] Figure 15 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 15, the contact structure CS3 is provided. Contrary to what was explained with reference to Figure 2, the first insulating spacer 142 and the contact insulating layer 130 constitute a single film. The first insulating spacer 142 and the contact insulating layer 130 are connected to each other without an interface between them. For example, the first insulating spacer 142 and the contact insulating layer 130 contain substantially the same material. For the sake of simplicity, the absence of an interface between the first insulating spacer 142 and the contact insulating layer 130 is represented by a dotted line between the first insulating spacer 142 and the contact insulating layer 130. An interface is formed between the first insulating spacer 142 and the second insulating spacer 162.

[0047] Figure 16 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 16, the contact structure CS4 is provided. Contrary to what was explained with reference to Figure 2, the first insulating spacer 142 and the second insulating spacer 162 constitute a single film. The first insulating spacer 142 and the second insulating spacer 162 are connected to each other without a boundary surface between them. The first insulating spacer 142 and the contact insulating layer 130 constitute a single film. The first insulating spacer 142 and the contact insulating layer 130 are connected to each other without an interface between them. For example, the first insulating spacer 142, the second insulating spacer 162, and the contact insulating layer 130 contain substantially the same material. For the sake of simplicity, the absence of an interface between the first insulating spacer 142 and the second insulating spacer 162, and between the first insulating spacer 142 and the contact insulating layer 130, is represented by dotted lines between the first insulating spacer 142 and the second insulating spacer 162, and between the first insulating spacer 142 and the contact insulating layer 130.

[0048] Figure 17 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 17, the contact structure CS5 is provided. Contrary to what was explained with reference to Figure 2, a cavity 174 is provided within the contact 172. For example, the cavity 174 is formed depending on the conditions during the process of forming the contact 172. Exemplary, the figure shows a cavity 174 provided within the contact 172 between the second insulating spacer 162 and the first conductive line 120. In one embodiment, the cavity 174 is formed in a contact 172 on the side surface of the second insulating spacer 162, or it is formed across the contact 172 between the second insulating spacer 162 and the first conductive line 120 and the contact 172 on the side surface of the second insulating spacer 162.

[0049] Figure 18 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 18, the contact structure CS6 is provided. Contrary to what was described with reference to Figure 2, the contact structure CS6 further includes a barrier film 176 that extends along the surface of the contact 172. The barrier film 176 is configured to protect other films (for example, the first insulating spacer 142, the second insulating spacer 162, and the first conductive line 120) when forming the contact 172. For example, the barrier film 176 may include one of the following: a titanium nitride film, a laminated film of a titanium film and a titanium nitride film, and a laminated film of a titanium film and a tungsten nitride film. The barrier film 176 is interposed between the contact 172 and the second insulating spacer 162. The barrier film 176 is interposed between the contact 172 and the first insulating spacer 142. The barrier film 176 is interposed between the contact 172 and the first conductive line 120. The barrier film 176 exposes the upper surface of the contact 172. For example, the upper surface of contact 172 is in direct contact with the second conductive line 180.

[0050] Figure 19 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 2. Referring to Figure 19, the contact structure CS7 is provided. Contrary to what was described with reference to Figure 2, the first insulating spacer 142 and contact 172 extend beyond the top surface of the first conductive line 120 toward the bottom surface of the first conductive line 120 (in the opposite direction to the third direction DR3). The lower ends of the first insulating spacer 142 and contact 172 are located at a height between the top and bottom surfaces of the first conductive line 120. The first insulating spacer 142 and contact 172 are superimposed on the top of the first conductive line 120 and along the first direction DR1. The side surface and bottom surface of the first insulating spacer 142, located on the opposite side of contact 172, are in contact with the first conductive line 120. The contact 172 extends further from the first insulating spacer 142 toward the bottom surface of the first conductive line 120. The lower end of the contact 172 is positioned at a height between the lower end of the first insulating spacer 142 and the bottom surface of the first conductive line 120. In one embodiment, the lower part of the contact 172 has a convex shape. The lower part of contact 172 is electrically connected to the first conductive line 120. For example, the lower part of contact 172 is in direct contact with the first conductive line 120.

[0051] Figure 20 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 19. Referring to Figure 20, a contact structure CS8 is provided. Contrary to what was described with reference to Figure 19, the contact structure CS8 further includes a barrier film 176 that extends along the surface of the contact 172. The barrier film 176 is configured to protect other films (for example, the first insulating spacer 142, the second insulating spacer 162, and the first conductive line 120) when forming the contact 172. For example, the barrier film 176 may include one of the following: a titanium nitride film, a laminated film of a titanium film and a titanium nitride film, and a laminated film of a titanium film and a tungsten nitride film. The barrier film 176 is interposed between the contact 172 and the second insulating spacer 162. The barrier film 176 is interposed between the contact 172 and the first insulating spacer 142. The barrier film 176 is interposed between the contact 172 and the first conductive line 120. The barrier film 176 exposes the upper surface of the contact 172. For example, the upper surface of contact 172 is in direct contact with the second conductive line 180.

[0052] Figure 21 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 19. Referring to Figure 21, a contact structure CS9 is provided. Contrary to what was described with reference to Figure 19, the contact 172 extends toward the bottom surface of the first conductive line 120 to substantially the same height as the first insulating spacer 142. The bottom surface of contact 172 is positioned at substantially the same height as the bottom surface of the first insulating spacer 142. For example, the bottom surface of contact 172 and the bottom surface of the first insulating spacer 142 are substantially coplane.

[0053] Figure 22 is a partial cross-sectional view showing a schematic configuration of a contact structure according to one embodiment of the present invention. To simplify the explanation, we will now explain the differences from what was explained using Figure 21. Referring to Figure 22, a contact structure CS10 is provided. Contrary to what was described with reference to Figure 21, the contact structure CS10 further includes a barrier film 176 that extends along the surface of the contact 172. The barrier film 176 is configured to protect other films (for example, the first insulating spacer 142, the second insulating spacer 162, and the first conductive line 120) when forming the contact 172. For example, the barrier film 176 may include one of the following: a titanium nitride film, a laminated film of a titanium film and a titanium nitride film, and a laminated film of a titanium film and a tungsten nitride film. The barrier film 176 is interposed between the contact 172 and the second insulating spacer 162. The barrier film 176 is interposed between the contact 172 and the first insulating spacer 142. The barrier film 176 is interposed between the contact 172 and the first conductive line 120. The barrier film 176 exposes the upper surface of the contact 172. For example, the upper surface of contact 172 is in direct contact with the second conductive line 180.

[0054] Furthermore, the present invention is not limited to the embodiments described above. It can be modified and implemented in various ways without departing from the technical scope of the present invention. [Explanation of symbols]

[0055] 10 Memory devices 110 Wiring insulation layer 120 First conductive line 130 Contact Insulation Layer 132 Spare contact holes 140 First insulating spacer film 142 First insulating spacer 150 molded film 152 Mold Patterns 160 Second insulating spacer film 162 Second insulating spacer 170 Spare Contact Film 172 Contacts 176 Barrier film 180 Second conductive line BE lower electrode BL Bitline CS1~CS10 Contact Structures CTH Contact Hole ML memory layer SOM Selector-Only Memory Element WL Wardline UE upper electrode

Claims

1. A contact insulating layer that defines the preliminary contact holes, A first insulating spacer extending along the side surface of the aforementioned spare contact hole, A second insulating spacer provided on the upper side surface of the first insulating spacer, The device has a contact that fills a contact hole defined by the first insulating spacer and the second insulating spacer, Each of the contacts provided on the bottom surface of the second insulating spacer and each of the contacts provided on the side surface of the second insulating spacer has a width that increases along the direction from the bottom surface to the top surface of the contact, A contact structure characterized in that the maximum width of the contact provided on the bottom surface of the second insulating spacer is greater than the minimum width of the contact provided on the side surface of the second insulating spacer.

2. The contact structure according to claim 1, further comprising a barrier film provided on the side and bottom surfaces of the contact.

3. The contact structure according to claim 2, characterized in that the barrier film exposes the upper surface of the contact.

4. The contact structure according to claim 1, characterized in that the first insulating spacer and the second insulating spacer constitute a single film.

5. The contact structure according to claim 1, characterized in that the contact insulating layer and the first insulating spacer constitute a single film.

6. The contact structure according to claim 1, characterized in that the side surface of the first insulating spacer is exposed on the bottom surface of the contact insulating layer.

7. The contact structure according to claim 1, characterized in that the side surface of the contact is exposed on the bottom surface of the first insulating spacer.

8. The contact structure according to claim 1, characterized in that the lower part of the contact has a convex shape.

9. A first conductive line electrically connected to the contact, The contact is provided with respect to the first conductive line on the opposite side and electrically connected to the contact, and further comprises: The contact structure according to claim 1, characterized in that the minimum distance between the first insulating spacer and the bottom surface of the first conductive line is smaller than the distance between the top surface of the first conductive line and the bottom surface of the first conductive line.

10. The contact structure according to claim 9, characterized in that the minimum distance between the contact and the bottom surface of the first conductive line is smaller than the minimum distance between the first insulating spacer and the bottom surface of the first conductive line.

11. The contact structure according to claim 9, characterized in that the second insulating spacer is separated from the first conductive line and in contact with the second conductive line.

12. A first conductive line extending in the first direction, A second conductive line extends in a second direction intersecting the first direction on the first conductive line, A contact provided between the first conductive line and the second conductive line, The contact includes a first portion adjacent to the first conductive line and a second portion adjacent to the second conductive line. Each of the first and second portions has a width that increases as it moves along the direction from the first conductive line toward the second conductive line, A contact structure characterized in that the maximum width of the first portion is greater than the minimum width of the second portion.

13. The contact structure according to claim 12, further comprising a barrier film provided on the side and bottom surfaces of the contact.

14. The contact structure according to claim 12, wherein the lower part of the contact has a convex shape.

15. The contact structure according to claim 12, characterized in that the minimum distance between the contact and the bottom surface of the first conductive line is smaller than the distance between the top surface of the first conductive line and the bottom surface of the first conductive line.

16. The contact structure according to claim 15, characterized in that the first conductive line has a side surface that is separated from and facing the side surface of the contact.

17. A word line extending in the first direction, A bit line extends in a second direction intersecting the first direction on the word line and is separated from the word line along a third direction perpendicular to the first and second directions, A selector-only memory element provided between the word line and the bit line, It has a plurality of contacts electrically connected to the word line and the bit line, respectively. Each of the plurality of contacts includes a first portion that is relatively far from the word line or the bit line and a second portion that is relatively close to the word line or the bit line. Each of the first and second portions has a width that increases as it goes along the third direction, A semiconductor memory device characterized in that the maximum width of the first portion is greater than the minimum width of the second portion.

18. The semiconductor memory device according to claim 17, further comprising a barrier film provided on each of the sides and bottom surfaces of the plurality of contacts.

19. The system further comprises a plurality of conductive lines that are electrically connected to the word line and the bit line, respectively, via the plurality of contacts. The semiconductor memory device according to claim 17, characterized in that the minimum distance between each contact and the bottom surface of each corresponding conductive line is less than the distance between the top surface of each conductive line and the bottom surface of each conductive line.

20. The system further comprises a plurality of conductive lines that are electrically connected to the word line and the bit line, respectively, via the plurality of contacts. The semiconductor memory device according to claim 17, characterized in that each of the conductive lines has a side facing and separated from the side of each of the contacts corresponding to them.

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