GB2410372A

GB2410372A - DRAM capacitors

Info

Publication number: GB2410372A
Application number: GB0500290A
Authority: GB
Inventors: Byung-Jun Park
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2002-06-27
Filing date: 2003-06-24
Publication date: 2005-07-27
Anticipated expiration: 2023-06-24
Also published as: GB2410374A; GB2410376A; GB2410373B; GB0500291D0; GB0500290D0; GB2410373A; GB2410374B; GB2410375B; GB0500295D0; GB0500293D0; GB2410375A; GB0500294D0; GB2410372B; GB2410376B

Abstract

The storage electrode of a DRAM semiconductor device comprises a series of fins 261 which are supported by an insulating member 245. The supporting member extends in a perpendicular direction to the direction in which the fins extend and prevents the storage electrode from bending or falling and making contact with an adjacent storage electrode.

Description

24 1 0372

SEMICONDUCTOR MEMORY DEVICES AND METHODS FOR

MANUFACTURING THE SAME USING SIDEWALL SPACERS

Field of the Invention

The present invention relates to semiconductor memory devices and methods for manufacturing the same, and more particularly to storage nodes for semiconductor memory devices and methods for manufacturing the same.

Backaround of the Invention

As semiconductor memory devices have become highly Integrated, the areas of isn't cells and the distances between cells may be reduced. However, capacitors having a large capacitance within small areas are desired, to provide predetermined capacitances. As is well known to those having skill in the art, semiconductor memory cievice capacitors include a lower electrode, also referred to as a storage node electrode, an upper electrode, also referred to as a plate electrode, and a dielectric layer therebetween. Conventional methods for securing large capacitances of the capacitors Include using a high dielectric material as the dielectric layer, reducing the thickness of a dielectric layer, and/or increasing the surface area of storage node electrodes of the capacitors.

A method tor increasing the surface area of the storage node electrodes includes forming three-dimensional storage node electrodes, for example, cylindrical or concave electrodes.

FIG. 1 is a sectional view illustrating conventional concave storage node electrodes.

Rcterring to FIG. 1, an interlevel insulating layer 12 is formed on a semiconductor substrate 10 having circuit devices (not shown), such as MOS transistors. The interlevel insulating layer 12 includes storage node contact plugs 14 that are widely known to connect a source region (not shown) of a selected MOS transistor with storage node electrodes 16, which will be formed m a subsequcut process. Thereafter, the cup-shaped concave storage node electrodes 16 are conned on the predetcrmmed portions of the storage node contact plugs 14 and the interlevel insulating layer 12. A method for forming the concave storage node electrodes 16 is 3() as follows. First, a mold oxide layer (not shown) having a predetermined thickness is deposited on the interlevel insulating layer 12 including the storage node contact plugs 14. The mold oxide layer is etched into hole shapes until exposing the storage node contact plugs 14, thereby defining a region for forming the storage node electrodes. Thereafter, a conductive layer (not shown) and a node isolation insulating layer (not shown) are subsequently bonged on the mold oxide layer so as to contact the exposed storage node contact plugs 14. The conductive layer and the node isolation insulating layer are chemical mechanical polished to expose the surface of the mold oxide layer. Thereafter, the node isolation insulating layer and the mold oxide layer are removed by a conventional method so that the concave storage node electrodes 16 are fonned.

However, the concave storage node electrodes formed by the abovedescribed method may have the following problems.

In order to manul'acturc the storage node electrodes having large capacitance, the height of the storage node electrodes may need to be increased within a limited area. In addition, in order to increase the height of the storage node electrodes, the thickness of the mold oxide layer may need to be increased. In this case, when the mold oxide layer is etched to define the region for forming the storage node electrodes, a large slope may occur on the sidewalls of the holes, and the critical dimension of the exposed storage node contact holes may be reduced. Accordmgly, 2() the lower portions of the thin and high storage node electrodes may become narrower so that the storage node electrodes may become unstable. In addition, the distance between adjacent storage node electrodes may be reduced so that it may be difficult to provide mslaton between the storage node electrodes.

Furthermore, due to thermal stress generated in subsequent processes, some of the weak storage node electrodes may fall or break and generate bridges between unit storage node electrodes, thereby causing defects in the device.

Summary of the Invention

An aspect of the present invention provides a semiconductor memory device 3() composing a semiconductor substrate, an nterlevel msulatmg layer on the semiconductor substrate, storage node contact plugs in the interlevel insulating layer, and storage node electrodes, which comprise a plurality of conductive hne patterns separated in predetermined intervals while having a predetermined height, contacting the storage node contact plugs, wherein, the storage node electrodes are separated by msulatmg One patterns between selected storage node electrodes in units of a unit cell of the memory device.

Another aspect of the present invention provides a semiconductor memory device comprising an interlevcl insulating layer on a semiconductor substrate S including a plurahty of active regions, a plurality of word line structures passing over the active regions, source and drain regions on the active regions at respective sides of the word line structures, and a plurality of bit line structures crossing the word line structures, electrically connecting to the drain regions, and passing between the active regions; etch stoppers on the interlevel insulating layer; storage node contact plugs 1 () Conned in the interlevcl insulating layer and the etch stoppers; storage node electrodes, which comprise a plurality of conductive line patterns separated in predetermined intervals while having a predetermined height, contacting to the storage node contact plugs; and supporters between the storage node electrodes and extending perpendicular to an extending direction of the line patterns of the storage node electrodes. In these embodiments, the plurality of line patterns are formed into straight lines.

Another aspect of the present invention provides a semiconductor memory device comprising an interlevel insulating layer on a semiconductor substrate including a plurality of active regions, a plurality of word line structures passing over the active regions, source and drain regions on the active regions at respective sides of the word brie structures, and a plurality of bit line structures crossing the word line structures, electrically comlecting to the drain regions, and passing between the active regions; etch stoppers on the interlevel insulating layer; storage node contact plugs in the interlevel insulating layer and the etch stoppers; storage node electrodes, which comprise a plurality ol'conductive line patterns separated in the same intervals while having a specific height, contacting the storage node contact plugs; and supporters between the storage node electrodes while being perpendicular to an extending direction of the line patterns of the storage node electrodes. In these embodiments, the plurality of line patterns are formed in the shape of waves in a plan view.

In another aspect ol'the present invention, there are provided methods of manufacturing a semiconductor memory device. In these methods, an interlevel msulatmg layer is deposited on a semiconductor substrate, and a plurality of storage node contact plugs are formed in the interlevel insulating layer in specific intervals.

Thereafter, mold oxide layer patterns are t'onmed on the intcrlevel insulating layer in specific intervals to expose the storage node contact plugs, and the spaces between the mold oxide layer patters are filled by alternately forming conductive line patterns and insulating line pattems, repeatedly, on the sidewalls of the mold oxide layer pattems. Grooves are formed perpendicular to the mold oxide layer patterns by etching portions of the mold oxide layer pattems, the conductive line patterns, and the hsulating hne patterns. Storage node electrodes are formed by selectively removing the mold oxide layer patterns and the insulating line patterns.

In a yet l;rther aspect of the present invention, there are provided methods for manufacturing a semiconductor memory device. In these methods, a semiconductor substrate, which includes a plurality of'active regions, a plurality of word line structures passing over the active regions, source and drain regions formed on the active regions at respective sides of the word line structures, and a plurality of bit line structures crossing the word brie structures, electrically connecting to the dram regions, and passing between the active regions, Is prepared. An interlevel insulating I layer is formed on the semiconductor substrate, etch stoppers are fonmed on the interlevel insulating layer, and storage node contact plugs are foamed m the interlevel insulating layer and the etch stoppers at specific intervals. Thereafter, a plurality of mold oxide layer patterns are formed on the etch stoppers at specific intervals to expose the storage node contact plugs. The spaces between the mold oxide layer 2() patterns are filled by alternately forming at least one conductive line pattern and insulating line pattern on the sidewalls of the mold oxide layer patterns in order to follow the shape of the mold oxide layer patterns. Grooves are formed perpendicular to the mold oxide layer patterns by etching portions of the mold oxide layer patterns, the conductive line pattems, and the Insulating line pattems. Thereafter, supporters are formed in the grooves, and storage node electrodes are formed by selectively removing the mold oxide layer patterns and the insulating line patterns. In these embodiments, the mold oxide layer patterns extend into straight lines and the mold oxide layer patterns and the supporters separate the storage node electrodes in units of each cell.

In a still other aspect ofthe present Invention, there are provided methods for manufacturing a semiconductor memory device. In these methods, a semiconductor substrate, which includes a plurality of active regions, a plurality of word line structures passing over the active regions, source and drain regions fonned on the active regions at respective sides of the word line structures, and a plurality of bit dine structures crossing the word line structures, electrically connecting to the drain regions, and passing between the active regions, Is prepared. An intcrlevel insulating layer is fonned on the semiconductor substrate, and etch stoppers are formed on the mterlevel insulating layer. Thereafter, storage node contact plugs are formed In the interlevel insulating layer and the etch stoppers at specific intervals, and a plurality of mold oxide layer pattems, which are formed n1 the shape of waves on a plan view, are formed on the etch stoppers to expose the storage node contact plugs. The spaces between the mold oxide layer patterns are filled by alternately fonning at least one conductive line pattern and hlsulathg line pattern on the sidewalls of the mold oxide layer patterns in order to follow the shape ol' the mold oxide layer patterns.

Thereafter, grooves are formed perpendicular to the mold oxide layer patterns by etching portions of the mold oxide layer patterns, the conductive line patterns, and the nsulatmg line patterns. Supporters are foamed in the grooves, and storage node electrodes are formed by selectively removing the mold oxide layer patterns and the insulating line patterns. In these embodiments, the mold oxide layer patterns and the supporters separate the storage node electrodes in units of each cell.

Another aspect of the present invention provides a storage node for a semiconductor memory device which includes a pair of spaced apart mold oxide layer patterns on a semiconductor memory device substrate that defiers facing mold oxide layer Fattens sidewalls. A pair of first conductive spacers are provided, a respective one of which is on a respective one of the facing mold oxide layer pattern sidewalls and face one another. A pair of first insulating spacer is provided, a respective one of which is on a respective one of the pair of first conductive spacers, opposite the respective one of the l'acmg mold oxide layer pattern sidewalls. A pair of second conductive spacers is provided, a r espective one of which is on a respective one of the pair of first Insulating spacers, opposite the respective one of the pair ol'first conductive spacers. At least one second insulating spacer is provided between the pair of second conductive spacers. In some embodiments, a single insulating spacer extends between the pair of second conductive spacers.

3() Storage nodes may be fabricated according to some embodiments of the present invention by forming spaced apart mold oxide layer patterns on a semiconductor memory device substrate that define facing mold oxide layer pattern sidewalls. A first conductive spacer is foamed on each of the facing mold oxide layer pattern sidewalls. A first insulating spacer is formed on each ofthe first conductive s spacers. A second conductive spacer is formed on each of the first insulating spacers and at least a second insulating spacer is formed on the second conductive spacers. In some embodiments, the first conductive spacers, the first insulating spacers and the second conductive spacers are formed by conformally fonning a conductive or insulating layer on the facing mold oxide layer pattern sidewalls and on the semiconductor memory device substrate therebetween, and then anisotropically etching the conductive or insulating layer to remove at least some the layer that is on the semiconductor memory device substrate therebetween.

In other embodiments of the invention, a storage node for a semiconductor memory device includes a plurality of freestanding storage node electrodes that project away from a semiconductor memory device substrate by a first distance. A supporter is configured to support at least one ofthe freestanding storage node electrodes and projects away from the semiconductor memory substrate by a second distance that is less than the first distance. In other embodiments, the plurality of freestanding storage nodes extend along two spaced apart rows, and the supporter extends between the two spaced apart rows. Storage nodes may be fabricated by forming the t'reestandhg storage node electrodes and then forming the supporter to support at least one of the freestanding storage node electrodes.

2() Brief Description of the Drawings

FIG. I is a sectional view illustrating a conventional semiconductor memory device having concave storage node electrodes; FIGS. 2A through 2D arc plan views of stages in the manufacture of a semiconductor memory device according to first embodiments of the present hlvention; FIGS. 3A through 3C arc sectional views of stages in the manufacture of a semiconductor memory device according to the first embodiments of the present mventon; FIG. 4 is a perspective view illustrating a semiconductor memory device according to the first embodiments of the present invention; FIG. S is a plan view illustrating a modified semiconductor memory device according to the first embodiments of the present invention; FIGS. 6A through ('D arc plan views of stages in the manufacture of a semiconductor memory device according to second embodiments of the present invention; FIGS. 7A and 7B are sectional views of stages in the manufacture of a semiconductor memory device according to the second embodiments of the present Invention; FIG. is a perspective view illustrating a semiconductor memory device according to the second embodiments of the present invention; 1; IG. 9 is a plan view illustrating a modified semiconductor memory device I () according to the second embodiments of the present invention; FIGS. 1 OA through I OC are sectional views of stages in the manufacture of a semiconductor memory device according to third embodiments of the present invention; FIGS. I 1 A through 1 ID are plan views of stages in the manufacture of a semiconductor memory device according to fourth embodiments of the present mvcntion; FIGS. I 2A and 1 2B are sectional views of stages in the manufacture of a semiconductor memory device according to the fourth embodiments of the present invention; FIGS. 13 and 14 are perspective views illustrating a semiconductor memory device according to the fourth embodiments of the present invention; FIG. 15 is a plan view illustrating a modi lied semiconductor memory device according to the fourth embodiments of the present invention; FIG. 16 is a plan view illustrating another modified semiconductor memory device according to the fourth cmbodments of the present invention; FIGS. I 7A and 1 7B are plan views of stages in the manufacture of a semiconductor memory device according to fifth embodiments of the present invention; and FIG. 18 is a plan view illustrating a modified semiconductor memory device 3() according to the fifth embodiments of the present invention.

Detailed Description

The present Invention now will be described more fully hereinafter with reference to the accompanying drawings, m which embodiments of the invention are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments arc provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawhlgs, the thickness of layers and regions are exaggerated for clarity. Like numbers refer to hke elements throughout.

It will be understood that when an element such as a layer, region or substrate is referred to as being "on" or extending "onto" another element, it can be directly on or extend directly onto the other element or intervening elements may also be present.

In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there are no intervening elements present.

First Embodiments Referring to FIGS. 2A and 3A, an isolation layer 110 is formed in a selected region of a semiconductor substrate 100 by a conventional STT method, thereby defining active regions 115 on which devices will be formed. Here, the semiconductor substrate 100 may be a silicon substrate including P-type or N-type impurities and may include weds in a predetermined region to form a device. The active regions 115, formed in, for example, a bar shape, are spaced apart by a predeterrnmed distance in rows and columns. Here, the active regions 115 are 9() arranged to alternate by each row. In other words, the spaces between the adjacent active regions 115 correspond to the central portions of the active regions of the subsequent row in the direction of the longer axis of the active regions 115. Here, the central portions of the active regions will be drain regions.

i hereafter, word line structures 120 are formed on the semiconductor substrate 100. Here, the word line structures 120 are extended to be parallel with one another while being perpendicular to the longer axis of the active regions 115. In addition, a pair of word line structures 120 may be arranged for each of the active regions 1 15. Source and drain regions (not shown) are formed in the active regions at both sides oi the word line structures 120 by a conventional method.

A first interlcvel msulathlg layer 130 is formed on the semiconductor substrate having the word line structures 120 and on the source and drain regions. First and second contact pads 140a and 140b, which contact the source and drain regions while having the same height as the first interlevel insulating layer 130, are formed in the first nterlevcl capsulating layer 130. A method tor forming the first and second contact pads 140a and 140b will now be described. After the first interlevel insulating layer 130 is formed, the first interlevel insulating layer 130 Is etched to expose the source and drain regions. A conductive layer, for example, a doped polysiLcon layer, is deposited to contact the exposed source and drain regions, and the conductive layer is etched back or chemical mechanical polished so as to expose the surface ol'the first interlevel insulating layer 130. Accordingly, the first and second contact pads 140a and 140b are Conned. Here, the first and second contact pads 140a and 140b contact the drain region and the source regions, respectively.

A second interlevel insulating layer 150 is fonned on the first interlevel hlsulathlg layer 130 and bit hne structures 165 are loomed on the second interlevel insulating layer 150. Here, the bit line structure 165 includes a bit line 160, a mask layer 162 formed on the bit line 160, and spacers 164 fonned on both walls of the bit line 160 and the mask layer 162. The mask layers 162 and the spacers 164, formed of, for example, silicon nitride layers, are formed to surround the bit lines 160 in order lo form self-aligned contact holes when forming storage node contact holes. In addition, n1 some embodiments, the bit line structures 165 are formed to be perpendicular to the word line structures 120 and that the bit line structures 165 are arranged on the isolation layer 110 between the active regions 115 while being parallel to the longer axis of the active regions. Here, though not shown in the drawings, bit line contact plugs for connecting the first contact pads 140a and the bit line structures 165 are formed in the second interlevel insulating layer 150 by a conventional method, before Donning the bit line structures 165.

A third interlevel insulating layer 170 and etch stoppers 175 are sequentially formed on the second interlevel insulating layer 150 having the bit line structures 165.

Here, the first through third interlevel insulating layers 130, 150, and 170 may be formed of, for example, insulating layers of the silicon oxide layer group. The etch stoppers 175 are formed of insulating layers, for example, silicon nitride layers, having an etchulg seleetivty different frown the etching seleetivities ofthe second and third interlevel insulating layers 150 and 170. The etch stoppers 175, the third interlevel insulating layer 170, and the second interlevel insulating layer 150 are etched to expose the second contact pads 140b, which contact the source regions, so that storage node contact holes 180 are formed. Here, the storage node contact holes are formed by a self- aligning method using the bit line structures 165. Thereafter, a conductive layer, for example, a doped polysilicon layer, is deposited to sufficiently illl the storage node contact holes 18O, and the doped polysilicon layer Is chemical mecllamcal polished to expose the etch stoppers 175. Accordingly, storage node contact plugs 185 are formed. Other conventional techniques lor tormmg a semiconductor memory device substrate may be used.

A mold oxide layer is fonned on the storage node contact plugs 185 and the etch stoppers 175 to a predetermined thickness. [n some embodiments, the mold oxide layer for determining the height of the storage node electrodes is formed to a height higher than the desired height of the storage node electrodes by a predctermmed height, considering that the mold oxide layer will be chemical l () mechanical polished to the predetermined height in the present embodiments. The mold oxide layer is etched to overlap the bit line structures 165 so that mold oxide layer patterns 190 are formed. Here, the mold oxide layer patterns 190 can be formed in predetermined intervals, for example, one-pitch or two-pitch. The mold oxide layer patterns l 90 of FIG. 2A are arranged in two-pitch intervals and the mold oxide layer patterns 190 of FIG. 5 are arranged in one-pitch intervals. In this respect, the mold oxide layer patterns 190 m the two-ptch intervals mean that two storage node contact plugs 185 are located between two adjacent mold oxide layer patterns 190. In addition, the line width of the mold oxide layer patterns 190 may be equal to or less than the line width ofthe bit line structures 165.

2() Referring to FIG. 3B, a conductive layer for the storage node electrodes, for example, a polysilicon layer, is deposited on the etch stoppers 175 on which the mold oxide layer patterns l 90 are formed. Next, the polysilicon layer is anisotropically etched to form conductive spacers 200 of polysilicon on both walls of the mold oxide layer patterns l 90. An insulating layer is deposited on the resultant structure and anisotropically etched to forth insulating spacers 220 on the sidewalls of the conductive spacers 200. By repeatedly forming the conductive spacers 200 and the insulating spacers 220, the spaces between the mold oxide layer patterns 190 are lolled. Marc, in order to separate unit cells, the last spacers formed between the mold oxide layer patterns 190, i.e., the spacers formed at the center points between the mold oxide layer patterns l 90, are the insulating spacers 220. In addition, the conductive spacers 200 are formed to contact the node contact plugs 185. In the present embodiments, the spaces between the mold oxide layer patterns 190 are filled by looming the conductive spacers 200 twice and forming the msulatmg spacers 220 twice; however, the widths and the numbers of the conductive spacers 200 and the insulating spacers 220 can be varied.

Referring to FIGS. 2B and 3C, the upper surfaces of the mold oxide layer patterns 190, the conductive spacers 200, and the Insulating spacers 220 are chemical S mechanical polished to planarize the upper surfaces so that conductive line patterns 201 and insulating line patterns 221 and 225 are fonned between mold oxide layer patterns 191. I:1ere, reference numeral 191 denotes the mold oxide layer patterns having planariz.ed tipper surfaces. And, the conductive line patterns 201 are the conductive spacers 220 having planarized upper surfaces, and the insulating line patterns 221 and 225 are the insulating spacers 220 having planarized upper surfaces.

The conductive line patterns 201 respectively contact the storage node contact plugs and the hlsulathg line patterns 221 and 225 insulate the conductive line patterns 201. In particular, the insulating line patterns 225 conned on the etch stoppers 175 separate the conductive line patterns 201 by one pitch, i.e., the size oLunit cells, in a l 5 direction parallel to the bit line structures 165 while insulating the conductive line patterns 201. In the present embodiments, each of the storage node contact plugs 185 includes, for example, two conductive line patterns 201 and one insulating line pattern 221 therebetween.

Referring to FIG. 2C, in order to define the storage node electrodes, grooves 2() 230 are formed by patterning portions of the mold oxide layer patterns 191, the conductive line patterns 201, and the insulating line patterns 221 and 225. Here, the grooves 230 extend to be perpendicular to the extending direction of the mold oxide layer patterns 191, he., to be parallel to the word line structures 120. The grooves 230 are formed between the word line structures 120 on which the drain regions are formed in order to secure maxhnum storage node electrode regions. In other words, a couple of word lines 120 are arranged between a couple of adjacent grooves 230 such that the grooves 230 open the etch stoppers 175.

Reierrblg to FIGS. 2D and 4, an insulating layer for supporters Is deposited to sufficiently bury the grooves 230, and the insulating layer is etched to a height smaller than the height of the conductive line patterns 201 so as to fowl supporters 240. Here, the insulating layer for supporters is formed of an Insulating layer having an etching selectivity different from the etching selectivties of the mold oxide layer patterns 191 and the insulating line patterns 221 and 225. Accordingly, the insulating layer is wet etched to form the supporters 240.

Since the supporters 240 are formed m the grooves 230, the supporters 240 cross through the conductive Ihle patterns 201 so that the supporters 240 separate the conductive brie patterns 201 according to cell. Furthennore, the supporters 240 support the conductive line patterns 201, thereby reducing or preventing the S conductive line patterns 201 from falling or bending toward the adjacent conductive hne patterns 201. In addition, the supporters 240 have a height smaller than the height of the conductiveline patterns 201 in order to secure storage node electrode capacitance.

Thereafter, the mold oxide layer patterns 191 and the insulating line patterns 221 and 225 are removed by a conventional wet etching method. Here, since the mold oxide layer patterns 191 and the insulating line patterns 221 and 225 have the etching selectivity difEcrent l'rom the etching selectivities ofthe etch stoppers 175 and the supporters 240, the mold oxide layer patterns 191 and the insulating hne patterns 221 and 225 are selectively removed. Thus, the storage node electrodes 250 formed 1 S of the plurality of conductive hue patterns 201 are completely formed.

The storage node electrodes 250 according to the present embodiment are formed ol'a plurality of conductive Ime patterns 201 having a fine line width so as to increase the surface area of the storage node electrodes 250. In addition, the supporters 240 separate and support the storage node electrodes 250 according to cell 2() so as to reduce or prevent the storage node electrodes 250 from falhng or bending toward the adjacent storage node electrodes 250. Furthermore, as shown in FIG. 2D, the storage node electrodes 250 are extended to the regions corresponding to the drain regions (not shown) as well as the regions having the bit line structures 165 so as to increase the surface area of the storage node electrodes 250.

Second Embodiments Ret'crring to FIGS. 6A and 7A, an isolation layer 110 is formed on a semiconductor substrate 100 as shown in the first embodiment to define active regions 115. Word hue structures 120 are Donned on the semiconductor substrate 100 as follows. Alter subsequently depostmg a gate Insulating layer 121, word lines 123, and a hard mask layer 125, the layers are patterned to be perpendicular to the longer axis of the active regions 115. Word line spacers 127 are formed on the sidewalls ofthe patterned hard mask layers 125 and word lines 123 by a conventional method to form the word line structures 120. Here, the hard mask layers 125 and the word line spacers 127 are formed of silicon nitride layers having an etching selectivity different from the etchmg selectivity of an interlevel insulating layer of a silicon oxide layer group, which will be romped to form self-aligning contact holes in a subsequent process. In addition, the word line structures 120 extend so as to be parallel with one another and a couple of word line structures 120 are arranged on each active region 115. Source and drain r enjoys (not shown), a first interlevel insulating layer 130, contact pads 140a and 140b, a second interlevel insulating layer 170, etch stoppers 175, and storage node contact pads 185 are fonned in the active regions 115 at both sides of the word line structures 120 by the method illustrated m the first embodiment.

A mold oxide layer is longed on the storage node contact plugs 185 and the etch stoppers 175 to a predetermined thickness. As described above, the mold oxide layer for determining the height of the storage node electrodes is Donned to a height higher than the desired height of the storage node electrodes by a predetermined height. The portion of the mold oxide layer Is etched to expose the storage node contact plugs 185, thereby forming mold oxide layer patterns 195. In the present embodiments, the mold oxide layer patterns 195 are arranged to be parallel to the word line structures 120 while overlapping the drain regions of the active regions 115.

In addition, the mold oxide layer patterns 195 can be formed in predetermined intervals, for example, one-pitch or two-pitch. The mold oxide layer patterns 195 of FIG. 6A are arranged in two-pitch intervals, and the mold oxide layer patterns 195 of FIG. 9 are arranged in one-ptch intervals. Here, the mold oxide layer patterns 195 In the two-pitch intervals mean that two storage node contact plugs 185 arc located between two adjacent mold oxide layer patterns 195, and the mold oxide layer patterns 195 in the one-pitch intervals mean that one storage node contact plug 185 is located between two adjacent mold oxide layer patterns 195.

Referring to FIGS. 6B and 7B, a conductive layer for the storage node electrodes, for example, a doped polysilicon layer, is deposited on the etch stoppers on which the mold oxide layer patterns 195 are formed as shown in the first 3() embodiment. The polysiLcon layer is anisotropically etched to form conductive spacers (not shown) of polyshcon on the both walls of the mold oxide layer patterns 195. An insulating layer is deposited on the resultant structure and anisotropically etched to form insulating spacers (not shown) on the sidewalls of the conductive spacers. By repeatedly forming the conductive spacers and the insulating spacers, the spaces between the mold oxide layer patterns 195 are filled. Here, the conductive spacers contact the storage node contact plugs 185 and the last spacers are the Insulating spacers. The last spacers are formed on the etch stoppers 175 between the storage node contact plugs 185 and the last spacers may have relatively larger line width than the other insulating spacers. In the present embodiments, each of the spaces between the mold oxide layer patterns 195 is filled by forming the conductive spacers four thnes and forming the insulating spacers four times; however, the widths and the numbers of the conductive spacers and the insulating spacers can be controlled.

The upper surfaces of the mold oxide layer patterns 195, the conductive spacers, and the insulating spacers are chemical mechanical polished to form conductive brie patterns 261 and insulating line patterns 271 and 275 between mold oxide layer patterns 196. Here, reference numeral 196 denotes the mold oxide layer patterns with planarized upper surfaces. The conductive line patterns 261, which are the conductive spacers having planarized upper surfaces, contact the storage node contact plugs 185. The insulating line patterns 271 on the storage node contact plugs 185, which are the insulating spacers 220 having planarized upper surfaces, insulate the conductive line patterns 261. In addition, the insulating line patterns 275 fonned on the etch stoppers 175 insulate the conductive hne patterns 261 and separate the 2() conductive brie patterns 261 in a direction parallel to the word line structures 120 by one pitch, i.e., cell unit. In the present invention, four conductive line patterns 261 contact each ofthe storage node contact plugs 185.

Referring to FIG. 6C, in order to define the storage node electrodes in each cell, grooves 235 are formed by patterning portions of the mold oxide layer patterns 196, the conductive line patterns 261, and the Insulating line patterns 271 and 275.

Here, the grooves 235 are fonmed to overlap the bit line structures 165. Accordingly, grooves 235 and the insulating spacers 275 separate the conductive line patterns 261 in units of unit cell.

Referring to FIGS. 6D and 8, an insulating layer for supporters is deposited to 3() sufficiently fill the grooves 235, and the insulating layer is etched to a height smaller than the height of the conductive line patterns 261 so as to forth supporters 245 In some embodiments, the insulating layer filled In the grooves 235 is fonned of an insulating layer having an etching selectivity different from the etching sclectivties of the mold oxide layer patterns 196 and the insulating hne patterns 271 and 275. Since the supporters 245 cross through the conductive line patterns 261, the supporters 245 separate the conductive line patterns 261 according to cell. Furthermore, the supporters 245 prevent the conductive line patterns 261 from falling or bending toward the adjacent conductive line patterns 261. In addition, the supporters 245 are formed to a height smaller than the height of the conductive line patterns 261 in order to secure storage node electrode capacitance.

Thercal'ter, the mold oxide layer patterns 196 and the insulating line patterns 271 and 275 are removed by a conventional wet etching method. Here, since the mold oxide layer patterns 196 and the insulating line patterns 271 and 275 have an l O ctchn1g sclectvity di 1'f'erent from the etching selectivities of the etch stoppers 175 and the supporters 245, the mold oxide layer patterns 196 and the insulating line patterns 271 and 275 are selectively removed. Thus, storage node electrodes 280 are completed.

The effects of the second embodiments can be the same as those of the first embodiments.

Third Embodiments FIGS. l OA through IOC are sectional views of stages in the manufacture of a semiconductor memory device according to third embodiments of the present invention. The descriptions of the elements that are the same as the first and second embodiments will not be repeated, and the same reference numerals are allotted for the same elements ol'the first and second embodiments. In addition, the present embodiments Include a method for forming storage node electrodes where the processes performed up until forming mold oxide layer patterns are the same as the processes of the first embodiments, thus the description will begin with the subsequent processes.

Referring to FIG. I OA, a first conductive layer 310 for storage node electrodes is formed on etch stoppers 175 on which mold oxide layer patterns 190 are formed.

Thereafter, an insulating layer 320 is deposited on the first conductive layer 310.

3() The first conductive layer 310 and the insulating layer 320 are anisotropically etched to form first conductive spacers 311 and insulating spacers 321 as shown m FIG. I OB A second conductive layer 330 Nor storage node electrodes Is deposited on the resultant structure. Here, the first conductive spacers 311 contact storage node contact plugs 185.

Next, by anisotropically etching the second conductive layer 330, second conductive spacers (not shown) are formed on the sidewalls of the insulating spacers 321. Here, the second conductive spacers contact the storage node contact plugs 185 while contacting the sidewalls of the first conductive spacers 311. As shown in FIG. 10C, the surl'ace of the resultant structure is chemical mechanical polished to form first conductive line patterns 312 formed ol'the first conductive spacers 311 and second conductive hne patterns 332 formed of the second conductive spacers. Here, the first conductive line patterns 312 are formed into an L-shape and portions of the second conductive line patterns 332 contact the lower portions of the first conductive line patterns 312. Thereafter, the insulating spacers 321 and the mold oxide layer patterns 190 are removed by a conventional wet etching method. Accordingly, storage node electrodes 300 formed of the first and second conductive line patterns 312 and 332 are formed.

Here, the storage node electrodes 300 are formed of two conductive line patterns; however, the widths and the numbers of the conductive line patterns can be varied.

In addition, the mold oxide layer is formed to be parallel to the bit line structures h1 the present embodiments; however, the mold oxide layer can be formed to be parallel to the word line structures as shown in the second embodiments.

Fourth Embodiments FIG. 12A and 12B are the sectional views cut along lines C-C' of FIGS. 11 A and 11 B. respectively.

The descriptions of the elements that are the same as the first through third embodiments will not be repeated, and the same reference numerals are allotted for the same elements of the first through third embodiments. In addition, in the present embodiments, the processes performed up until forming storage node contact plugs are the same as the processes of the first through third embodiments, thus the description will begin with the subsequent processes.

3() Referring to FIGS. I I A and 12A, a mold oxide layer is formed on storage node contact plugs 185 and etch stoppers 175 to a predetermined thickness. Here, the mold oxide layer for determining the height of storage node electrodes can be formed to the desired height of the storage node electrodes. Thereafter, portions of the mold oxide layer are dry etched to form a plurality of mold oxide layer patterns 400. Here, the mold oxide layer patterns 400 are formed in, for example, one-pitch intervals, while being f'omed m the shape of waves on a plan view. In other words, ridge portions X of the mold oxide layer patterns 400 located between the storage node contact plugs 185 and valley portions X2 of the mold oxide layer patterns 400 are located on drain regions, which correspond to first contact pads 140a, or on an isolation layer 110 corresponding to the drain regions. When connecting the ridge portions X' of the wave-shaped mold oxide layer patterns 400, straight lines are formed. In addition, in some embodiments, the straight lines are parallel to bit lines strctcres 165.

I () As shown m FIGS. I l B and 12B, a conductive layer 410 for storage node electrodes, for example, a doped polysilicon layer, is deposited on etch stoppers 175 on which the wave-shaped mold oxide layer patterns 400 are formed, and a buffer insulating layer 420 is deposited on the conductive layer 410 for storage node electrodes. Thereafter, a chemical mechanical polishing is performed to expose the mold oxide layer patterns 400. Accordingly, the conductive layer 410 for storage node electrodes remains in a region defined by the mold oxide layer patterns 400 Here, the sidewalls ofthe remaining conductive layer 410 for storage node electrodes have the same wave shape as the mold oxide layer patterns 400.

Next, as shown in FIGS. 11 C and 13, grooves 430 are formed by dry etching portions of the mold oxide layer patterns 400, the conductive layer 410 for storage node electrodes, and the insulating layer 420 in order to separate the storage node electrodes by cell. Here, the grooves 430 are formed between word line structures 120, on which dram r egions (not shown) are formed, while being perpendicular to the extending direction of the mold oxide layer patterns 400, i.e., the direction of bit line structures. It is prel'erable that the grooves 430 pass through the valley portions X2 of the mold oxide layer patterns 400.

Thereafter, as shown in FIGS. 11 D and 14, an insulating layer for supporters is deposited to sufficecntly fill the grooves 430. Here, the insulating layer for supporters can be formed of the same material as the etch stoppers 1 75, for example, a silicon nitride layer. The insulating layer is wet or dry etched to a predetermined thickness so that the insulating layer is remained in the grooves 430 to a height smaller than the height of the conductive layer 410 for storage node electrodes or the mold oxide layer patterns 400. Accordingly, supporters 440 are formed.

The mold oxide layer patterns 400 and the insulating layer 420 are removed by a conventional wet etching method to forth storage node electrodes 425. Here, since the etch stoppers 175 are fonned on the resultant structure on the semiconductor substrate 100 and the etching selectivity of the supporters 440 is different from the etching sclectivities of the mold oxide layer patterns 400 and the insulating layer 420, only the mold oxide layer patterns 400 and the insulating layer 420 are selectively removed Thus, the storage node electrodes 425 are defined in units of each cell. In other words, the storage node electrodes 425 are separated in units of each cell by the supporters 440 in a direction parallel to the word lines. In addition, the supporters l() 440 formed in specific intervals support the storage node electrodes 425, which are Conned into wave-shaped line patterns. Therefore, the narrow and high storage node electrodes 425 are prevented from falling toward the adjacent storage node electrodes 425.

According to the present embodiments, since the storage node electrodes 425 l 5 are formed in the wave shape, the surface area of the storage node electrodes 425 increases. In addition, since the storage node electrodes 425 are extended to the drain regions or the regions corresponding to the drain regions, the surface area of the storage node electrodes 425 further increases.

Furthermore, since the supporters 440 are formed to separate the storage node electrodes 425 In units of each cell, the storage node electrodes 425 are reduced or prevented from falling or bending toward the adjacent storage node electrodes 425.

Here, the mold oxide layer patterns can be formed by changing the intervals of the wave as shown In FIG. 15.

Referring to FIG. 15, mold oxide layer patterns 450 are fonmed in the shape of waves in a plan view. Here, ridge portions X3 and valley portions X4 are formed to be located between storage node contact plugs 185. In this case, lines formed by cormecthlg the ridge portions X3 and lines formed by connecting the valley portions X4 are parallel with one another by a predetermined distance, which is wider than the width of the active regions.

Il'the wave shape of the mold oxide layer patterns 450 is changed, the same effect is attained.

In addition, as shown in FIG. 16, mold oxide layer patterns 500 may be fowled in two-pitch intervals. In other words, the mold oxide layer patterns 500 are arranged m two-pitch intervals as shown in the first embodiment while being formed In the shape of waves on a plan view. For example, in the mold oxide layer patterns 500, ridge portions X' may be located between storage node contact plugs 185, and valley portions X2 may be located on drain regions, i.e., first contact regions, or on an isolation layer l lO corresponding to the drain regions. If the mold oxide layer patterns 500 in two-pitch intervals are Conned, the same effect is attained.

In addition, storage node electrodes 425 can be formed by the method perlonned in the third embodiments.

Fifth Embodiments l O FIGS. 17A and 17B are plan views of stages in the manufacture of a semcondtctor memory device according to fifth embodiments of the present invention. The processes performed up until Donning etch stoppers 175 are the same as the processes of the first and second embodiments, thus the description will begin with the subsequent processes.

Referring to FIGS. 17A, mold oxide layer patterns 600 are formed in the shape of waves In a plan view, on etch stoppers 175. Here, the mold oxide layer patterns 600 can be formed in, for example, one-pitch intervals. In other words, lines formed by connecting ridge portions X5 or valley portions X6 of the mold oxide layer patterns 600 are substantially parallel to word line structures 120. In addition, the mold oxide 2() layer patterns 600 are formed to expose each of the storage node contact plugs 185 between the adjacent mold oxide layer patterns 600 on the same lines. The mold oxide layer patterns 600 are formed on regions without storage node contact plugs, i.e., on drain regions and on an isolation layer 110 corresponding to the drain regions.

A plurality of conductive line patterns 610 and insulating line patterns 620 are alternately Conned between the mold oxide layer patterns 600. Here, the plurality of conductive line patterns 610 and insulating line patterns 620 are formed into waves according to the wave-shaped mold oxide layer patterns 600. In this case, the conductive line patterns 610 and the insulating line patterns 620 are formed by the above-described methods.

As shown in FIG. 17B, portions of the mold oxide layer patterns 600, the conductive line patterns 610, and the insulating line patterns 620 are etched to form grooves 630. The grooves 630 are fonned on regions, which overlap bit line structures 165, in order to separate the conductive line patterns 610 in units of each cell. Here, the conductive line patterns 610 are defined in units of each cell by the grooves 630 and the mold oxide layer pattern 600, and the conductive line patterns 610 are formed into waves while contacting the storage node contact plugs 185.

Thereafter, supporters (not shown) are formed in the grooves 630 by the above-described method. The mold oxide layer patterns 600 and the insulating line patterns 620 are etched to form storage node electrodes 625.

If the mold oxide layer patterns 600 are fonned to be parallel to the word line structures 120, the same el'Pect may be attained.

As shown In FIG. 18, the same effect may be attained by forming the mold oxide layer patterns 700 into waves n1 two-pitch intervals.

I () As described above, according to embodiments of the present invention, storage node electrodes are formed in a plurality of line pattern types having a fine lme width. Thus, the surface area of the storage node electrodes can increase. In addition, the supporters fonned of an insulating layer are formed to be perpendicular to the extending direction of the line patterns of the storage node electrodes.

Therefore, the supporters separate the storage node electrodes in units of each cell, and the supporters support the storage node electrodes, thereby reducing or preventing the storage node electrodes from falhng or bending toward the adjacent storage node electrodes.

Furthermore, the regions for forming the storage node electrodes may be increased so that the surface area of the storage node electrodes may be Increased.

While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.

Claims

CLAIMS: I A semiconductor memory device comprising: a semiconductor

substrate including a plurality of active regions, a plurality of word line structures passing over the active regions, source and drain regions on the active regions at respective sides of the word line structures, and a plurality of bit line structures crossing the word line structures, electrically connecting to the drain regions, and passing between the active regions; an interlevel insulating layer on the semiconductor substrate; etch stoppers on the interlevel insulating layer; 1() storage node contact plugs in the interlevel insulating layer and the etch stoppers; storage node electrodes, which comprise a plurality of conductive line patterns separated in predetermined intervals while having a predetermined height, contacting the storage node contact plugs; and supporters between the storage node electrodes, the supporters extending perpendicular to an extending direction of the line patterns of the storage node electrodes; whirred, the plurality of line patterns comprise straight lines.

2. The semiconductor memory device of claim 1, wherein the conductive line patterns are extended to be substantially parallel to the bit line structures; and the supporters are substantially parallel to the word line structures and pass over the drain regions between the word line structures and an isolation layer corresponding to the drain regions.

3. The semiconductor memory device of claim 1 or 2, wherein the conductive line patterns are extended to be substantially parallel to the word One structures; and the supporters are substantially parallel to the bit line structures and overlap 3() each of the bit hne structures.

4. The semiconductor memory device of claim I, 2 or 3, wherein the supporters have a height smaller than the height of the line patterns.

5. The semiconductor memory device of any of claims 1 to 4, wherein the supporters comprise insulating layers.

6. A method tor manufacturing a semiconductor memory device, the method comprising: preparing a semiconductor substrate including a plurahty of active regions, a plurality ol word line structures passmg over the active regions, source and drain regions formed on the active regions at respective sides of the word line structures, and a plurality of bit line structures crossing the word line structures, electrically 1 () connecting to the drain regions, and passing between the active regions; forming an interlevel insulating layer on the semiconductor substrate; forming etch stoppers on the interlevel insulating layer; forming storage node contact plugs in the interlevel insulating layer and the etch stoppers at specific intervals; forming a plurality of mold oxide layer patterns on the etch stoppers at specific intervals to expose the storage node contact plugs; filling spaces between the mold oxide layer patterns by alternately forming at least one conductive line pattern and insulating line pattern on the sidewalls of the mold oxide layer patterns U1 order to follow the shape of the mold oxide layer patterns; forming grooves substantially perpendicular to the mold oxide layer patterns by etching portions of the mold oxide layer patterns, the conductive line patterns, and the insulating brie patterns; Conning supporters in the grooves; and forming storage node electrodes by selectively removing the mold oxide layer patterns and the insulating line patterns; wherein the mold oxide layer patterns extend into straight lines and the mold oxide layer patterns and the supporters separate the storage node electrodes in units ot each cell. 3()

7. The method for manufacturing a semiconductor memory device of claim 6, wherein the mold oxide layer patterns are formed so that each of the storage node plugs Is between the adjacent mold oxide layer patterns.

8. The method for manufacturing a semiconductor memory device of clam 6, wherein the mold oxide layer pattems are ford so that two storage node plugs are between the adjacent mold oxide layer patterns on the same Ones.

9. The method lor manufacturing a semiconductor memory device ol clam 6, 7 or 8, wherem the mold oxide layer patterns are formed to be parallel to the bit hne structures I () I he method for manufacturing a semiconductor memory device of I () clanks 6' 7 or 8, whcrem the mold oxide layer patterns are formed to be parallel to the vord Imc structures.

I I. The method for manufacturing a semiconductor memory device of clang I (), wherein the mold oxide layer patterns are formed on the drain regions between the word line structures and an isolation layer region corresponding to the Shrank regions 12 The method for manufacturing a semiconductor memory device of any of clams 6 to 1 1, wherein the tilling ol the spaces between the mold oxide layer 2() patterns ushig the conductive hne patterns and the insulating hne patterns composes: formmg conciuctve spacers on the sidewalls of the mold oxide layer pattems; formals, msulatng spacers on the sidewalls of the conductive spacers; repeating the iomnng of the conductive spacers and the fowling of the insulating spacers al least once; and chemical mechanical polishing the mold oxide layer, the conductive spacers, and the insulating spacers lo form the conductive Ime patterns and the insulating line paltems.

13. I he method for manulaclunng a semiconductor memory device o f claim 12, wherein the conductive spacers are formed to contact the storage node contact plugs.

14. The method for manufacturing a semiconductor memory device of claim 12 or 13, wherein the insulating spacers are finally formed in the repeatedly fonnmg the conductive spacers and the insulating spacers.

15. The method for manufacturing a semiconductor memory device of any of claims 6 to I I, wherein the filling spaces between the mold oxide layer patterns using the conductive line patterns and the insulating line patterns comprises: depositing a first conductive layer on the interlevel insulating layer and the mold oxide layer patterns; I () forming an insulating layer on the first conductive layer; forming first conductive spacers and insulating spacers by anisotropically etching the insulating layer and the Fret conductive layer; fonnmg second conductive spacers on the sidewalls of the insulating spacers; and chemical mechanical polishing the mold oxide layer patterns, the first conductive spacers, the insulating spacers, and the second conductive spacers.

16. The method lor manufacturing a semiconductor memory device of claim 6, wherein the forming supporters comprises: depositing an insulating layer to fill the grooves; and etching the insulating layer so the insulating layer remains in the grooves.

17. The method for manufacturing a semiconductor memory device of claim 16, wherein the insulating layer is etched by a wet etching method.

18. The method for manufacturing a semiconductor memory device of claim 16 or 17, wherein the insulating layer is etched to have a height smaller than the height of the conductive line pattems.

3() 19. The method for manufacturing a semiconductor memory device of claim 16, 17 or 18, wherein the insulating layer composing the supporters has an etching selectivity different from the etching selectivities of the mold oxide layer patterns and the insulating line patterns.