KR20070058054A - Method of manufacturing the phase-changeable memory device - Google Patents

Abstract

A method for manufacturing a phase change memory device is provided to prevent the damage of a sidewall of a phase change material pattern and to prevent a bonding failure at an interface between an upper electrode and the phase change material pattern by lessening a thermal stress applied to the upper electrode and the phase change material pattern using an improved capping structure composed of first capping layer formed at a first temperature and a second capping layer formed at a second temperature. A contact pad(120) for contacting a substrate(100) is formed through a first insulating pattern(110). A second insulating pattern(130) having a lower contact electrode(140) is formed on the resultant structure, wherein the lower contact electrode is electrically connected with the contact pad. A phase change material layer and an upper electrode layer are formed on the resultant structure. An upper electrode(160) and a phase change material pattern(150) are formed by patterning selectively the upper electrode layer and the phase change material layer using a mask pattern. A first capping layer(170) is formed on the resultant structure in a first temperature range. Then, a second capping layer(180) is formed on the first capping layer in a second temperature range.

Description

Manufacturing method of phase change memory device {METHOD OF MANUFACTURING THE PHASE-CHANGEABLE MEMORY DEVICE}

1 is a scanning electron micrograph showing a problem of a phase change memory device.

2 is a cross-sectional view illustrating a phase change memory device according to an exemplary embodiment of the present invention.

3 to 7 are process cross-sectional views illustrating a method of manufacturing the phase change memory device shown in FIG. 2.

<Description of the code | symbol about the principal part of drawing>

100: semiconductor substrate 110: first insulating film pattern

120 contact pad 130 second insulating film pattern

140: lower contact electrode 150: phase change material film pattern

160: upper electrode 170: first capping film

180: second capping film 190: upper contact electrode

195: metal wiring

The present invention relates to a method of manufacturing a phase change memory device. Specifically, the present invention relates to a method of manufacturing a phase change memory device manufactured using a phase change material according to heat.

Examples of semiconductor memory devices widely used in recent years include DRAM, SRAM, Flash memory, and the like. Such semiconductor devices may be largely divided into volatile memory devices and nonvolatile memory devices according to whether data is retained when power supply is interrupted. Memory devices used for data storage of digital cameras, MP3 players and mobile phones are mainly used non-volatile memory devices, especially flash memory to store data even without a power supply.

However, the flash memory is not a random access memory (RAM), which requires a lot of time to read or write data, and thus a new semiconductor device has been required. As such a new next-generation semiconductor device, Ferro-Electric RAM (FRAM), Magentic RAM (MRAM), phase change memory device: Phase-change RAM (PRAM) and the like have been proposed.

Among them, a phase change memory device uses a phase change material whose crystal state changes between a crystal structure and an amorphous structure depending on heat provided thereto. Typically, chalcogenides composed of germanium (Ge), antimony (stibium; Sb), and tellurium (Te) are used as phase change materials.

In order to provide heat to the phase change material, a current flows through the phase change material film. That is, the crystal state of the chalcogenide compound changes depending on the magnitude of the current supplied and the supply time. Because the size of the resistor varies with the crystal state (the crystal state is low in resistance and the amorphous state is high in resistance), the logic difference can be determined by detecting the difference in resistance.

In order to form a phase change memory device having such characteristics, first, a first insulating layer pattern including a metal wire electrically connected to an impurity region of a semiconductor substrate is formed. A second insulating film having an opening on which the spacer is formed is formed on the first insulating film. A contact electrode buried in the opening is formed. Subsequently, a phase change material layer pattern and an upper electrode which electrically connect the contact electrode are sequentially formed on the second insulating layer. After the capping layer is formed on the resultant to form an upper contact electrode for electrically connecting the upper electrode and the upper wiring. As a result, a phase change memory device is formed.

Since the phase change material included in the phase change memory device formed by the above method has a characteristic of volatilizing at 320 ° C. to 350 ° C., the etch mask and the capping layer which are used to form the phase change material layer pattern are described above. It should be formed at a temperature lower than the temperature. In addition, the process progress temperature after the capping film should also be made below 400 ° C.

However, since the process after the capping film for forming the phase change memory device is a heat treatment process of 400 ℃ is applied to the interface between the phase change material film pattern and the upper electrode as shown in the SEM photograph of FIG. A problem has occurred. In addition, there is a problem that the side of the phase change material film pattern is lost (R). The above-mentioned problems cause a poor interface bonding between the phase change material film pattern and the upper electrode, resulting in deterioration of electrical characteristics of the phase change memory device.

It is an object of the present invention to provide a method of manufacturing a phase change memory device capable of preventing a bonding failure of an upper electrode electrically connected to a phase change material film pattern.

According to the manufacturing method of the phase change memory device of the present invention for achieving the above object, first, a conductive material is buried in the opening formed in the first insulating film pattern to form a contact pad electrically connected to the substrate. Subsequently, a lower contact electrode penetrates through the second insulating film pattern formed on the first insulating film pattern and is electrically connected to the contact pad. A phase change material layer is formed on the lower contact electrode and the second insulating layer pattern. After forming an upper electrode layer on the phase change material layer, a mask is applied to sequentially pattern the upper electrode layer and the phase change material layer to form an upper electrode and a phase change material layer pattern. After forming a first capping film formed at a first temperature on the resultant to form a second capping film formed at a second temperature higher than the first temperature on the first capping film. As a result, a phase change memory device having a smooth flow of current between the metal wiring and the contact electrode is formed.

As an example, the first temperature for forming the first capping film is preferably 180 to 230 ° C., and the first capping film is a silicon nitride film formed by performing an enhanced plasma chemical vapor deposition process. In addition, the second temperature for forming the second capping film is preferably 380 to 420 ℃, the second capping film is formed by performing an enhanced plasma chemical vapor deposition process, characterized in that it comprises silicon nitride Method of manufacturing a phase change memory device.

Since the phase change memory device manufactured by the above method includes the first capping film formed at the first temperature and the second capping film formed at the second temperature, the upper electrode and the phase change material film pattern at the process temperature after the capping film. It can alleviate the thermal stress applied to it. Therefore, the sidewalls of the phase change material film pattern included in the phase change memory device may be prevented from being lost. In addition, since the upper electrode and the phase change material film pattern are not bent due to thermal stress, poor interface bonding characteristics between the upper electrode and the phase change material film pattern can be prevented. As a result, the degradation of the information storage speed and the information erasing capability of the phase change memory device can be prevented.

Hereinafter, the present invention will be described in detail with reference to embodiments according to the present invention. However, the present invention is not limited to the following examples and may be implemented in other forms. The embodiments introduced herein are provided to make the disclosure more complete and to fully convey the spirit and features of the invention to those skilled in the art.

2 is a cross-sectional view illustrating a phase change memory device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a phase change memory device includes a first insulating film pattern 110 formed on a substrate 100, a contact pad 120 penetrating the first insulating film pattern, and a contact hole exposing the contact pad. The second insulating layer pattern 130, the lower contact electrode 140 formed in the contact hole, the phase change material layer pattern 150, the upper electrode 160, the mask 165, the first capping layer 170, and the second The capping layer 180, the third insulating layer pattern 185, the upper contact electrode 190, and the metal wire 195 are included.

The first insulating layer pattern 110 is formed on the substrate 100 on which lower structures (not shown) are formed, and receives an opening (not shown) for receiving the contact pad 120 electrically connected to the semiconductor substrate 100 among the lower structures. City). The first insulating layer pattern 110 includes oxides such as boro-phosphor silicate glass (BPSG), phosphor silicate glass (PSG), undoped silicate glass (USG), spin on glass (SOG), tetraethylorthosilicate (TEOS), and the like.

The contact pad 120 is provided in an opening formed in the first insulating layer pattern 110 and is electrically connected to an impurity region included in the substrate 100. The contact pad 120 may include a material such as titanium (Ti), aluminum, tungsten (W), tantalum (Ta), tantalum nitride (TaN), or the like. The contact pad 120 may include a single or a plurality of the above-mentioned materials.

The second insulating layer pattern 130 is provided on the first insulating layer pattern 110. The second insulating layer pattern 130 includes a contact hole in which the lower contact electrode 140 is electrically connected to the contact pad 120. The second insulating layer pattern 130 defines a region in which the lower contact electrode 140 is formed while the phase change material layer pattern 150 formed later is spaced apart from the contact pad 120. Although not shown in the drawings, for example, when the margin of the photo process for forming the contact hole is insufficient, the lower contact electrode 140 may further include a spacer on the sidewall to have a width smaller than the diameter of the contact hole.

The lower contact electrode 140 is provided in the contact hole and is electrically connected to the contact pad 120. The contact electrode 160 is a path through which the current of the contact pad 120 flows into the phase change material film pattern 150 so as to obtain a relatively high resistance to the phase change material film pattern 150 with a minimum current. Do it.

The phase change material layer pattern 150 is provided with the lower contact electrode 140 and the second insulating layer 130 and includes a chalcogenide compound. Examples of such chalcogen compounds are germanium-antimony-tellurium (GST), arsenic-antimony-tellurium, tin-antimony-tellurium, tin-indium-antimony-tellurium, arsenic-germanium-antimony-tellurium, tantalum, Group 5A elements such as niobium to vanadium-antimony-tellurium, tungsten, molybdenum to chromium and the like, Group 6A elements-antimony-tellurium, group 5A elements-antimony-selen, or group 6A elements-antimony-selen have.

The upper electrode 160 is formed on the phase change material film pattern 150 and includes a conductive material included in the lower contact electrode 140. The mask 165 is provided on the upper electrode and includes silicon nitride.

The first capping layer 170 may have a substantially uniform thickness on the top and side surfaces of the structure including the phase change material layer pattern 150, the upper electrode 160, and the mask 165. It is a first silicon nitride film formed at about 180 to 230 ° C.

The second capping layer 180 is a second silicon nitride layer having a substantially uniform thickness on the first capping layer and formed at a second temperature of about 380 to 420 ° C. The second capping layer serves to relieve thermal stress generated in a subsequent process together with the first capping layer.

The upper contact electrode 190 is formed through the third insulating layer pattern 185 covering the second capping layer, the second capping layer 180, the first capping layer 170, and the mask 165. It is electrically connected to the electrode 160. The upper contact electrode 190 includes the same material as the lower contact electrode 140.

Since the phase change memory cell having the above-described structure includes a first capping film formed at a first temperature and a second capping film formed at a second temperature, the phase change memory cell is formed on the upper electrode and the phase change material film pattern at a process temperature after the capping film. It can alleviate the thermal stress applied. Therefore, the degradation of the information storage speed and the information erasing capability of the phase change memory device can be prevented.

3 to 7 are process cross-sectional views illustrating a method of manufacturing the phase change memory device shown in FIG. 2.

Referring to FIG. 3, a first insulating layer pattern 110 including the contact pad 120 is formed on a semiconductor substrate 100 on which a transistor (not shown) is formed.

In detail, a first insulating layer (not shown) is formed on a substrate on which a lower structure such as a transistor is formed. The insulating film is formed by performing a chemical vapor deposition process, and includes silicon oxide. Examples of the silicon oxide contained in the first insulating film include TEOS, USG, SOG, HDP-CVD oxide, and the like. Subsequently, the first insulating layer is patterned by a photolithography process to form openings (not shown) for selectively exposing the impurity regions of the transistor. Subsequently, the first insulating layer is formed of the first insulating layer pattern 110 due to the contact hole formation.

Subsequently, a pad conductive film covering the insulating film pattern is formed while the opening included in the first insulating film pattern is buried. The conductive film is formed by depositing aluminum, titanium, titanium nitride, tantalum, tungsten, or the like. Subsequently, a chemical mechanical polishing process is performed to expose the top surface of the first insulating layer pattern. As a result, a contact pad 120 electrically connected to the impurity region included in the substrate and embedded in the opening is formed.

Referring to FIG. 4, a second insulating film pattern 130 formed on the first insulating film pattern 110 including the contact pad 120 and having a contact hole (not shown) exposing a surface of the contact pad is formed. To form.

In detail, first, a second insulating film (not shown) having a thickness of about 700 GPa is formed on the first insulating film pattern through which the contact pad penetrates. Thereafter, a contact hole for exposing the contact pad is formed by selectively patterning the second insulating layer by performing a photolithography process. As the contact hole is formed, the second insulating layer is formed as the second insulating layer pattern 130.

Although not shown in the drawing, a contact electrode 140 having a structure surrounded by a spacer is formed in the contact hole of the second insulating layer pattern 130. Specifically, a nitride film (not shown) is continuously formed on the second insulating layer pattern 130 on which the contact hole is formed, and then etched back. As a result, a spacer is formed on the side surface of the contact hole.

Subsequently, a conductive film for the lower contact electrode is formed to bury the contact hole. The conductive film may be formed of a chemical vapor deposition method, a sputtering method by using a metal such as tantalum, copper, tungsten, titanium, aluminum, or a compound such as nitride thereof. It can be formed by the same physical vapor deposition method or atomic layer deposition method. Subsequently, the conductive layer is etched back until the top surface of the second insulating layer pattern 130 is exposed. As a result, a lower contact electrode 140 is formed in the contact hole and electrically connected to the contact pad.

Referring to FIG. 5, a phase change material film 150a is formed on the second insulating film pattern 130 including the lower contact electrode 140. The phase change material film 150a is formed by a sputtering method using a chalcogen compound.

Examples of such chalcogen compounds are germanium-antimony-tellurium (GST), arsenic-antimony-tellurium, tin-antimony-tellurium, tin-indium-antimony-tellurium, arsenic-germanium-antimony-tellurium, tantalum, Group 5A elements such as niobium to vanadium-antimony-tellurium, tungsten, molybdenum to chromium and the like, Group 6A elements-antimony-tellurium, group 5A elements-antimony-selen, or group 6A elements-antimony-selen have. Preferably, the phase change material film 150a is formed to have a thickness of about 500 to 1000 kW using germanium-antimony-tellurium (GST).

Next, the upper electrode layer 160a is formed on the phase change material film 150a by using a chemical vapor deposition process, a physical vapor deposition process, or an atomic layer deposition process. The upper electrode layer 160a is formed using a conductive material, a metal, or a metal silicide containing a nitrogen element. The conductive material containing the nitrogen element may include titanium nitride, tantalum nitride, molybdenum nitride, titanium-silicon nitride, titanium-aluminum nitride, titanium-boron nitride, zirconium-silicon nitride, tungsten-silicon nitride, tungsten-boron nitride, Zirconium-aluminum nitride, molybdenum-silicon nitride, molybdenum-aluminum nitride, tantalum-silicon nitride, tantalum-aluminum nitride, titanium oxynitride, titanium-aluminum oxynitride, or tungsten oxynitride, tantalum oxynitride. In addition, any conductive material capable of flowing a sufficient current as a conductor can be used.

Referring to FIG. 6, after forming a mask 165 defining a layout of a phase change element on the upper electrode layer, the upper electrode layer 160a and the phase change material layer 150a exposed to the mask are formed. Patterning sequentially. As a result, the phase change material film pattern 150 and the upper electrode 160 are formed.

Referring to FIG. 7, a first capping layer 170 formed at a first temperature and a second capping layer 180 formed at a second temperature higher than the first temperature are formed on the resultant.

In detail, a first thickness having a substantially uniform thickness on the top surface, the side surface, and the second insulating layer pattern 130 of the structure including the phase change material layer pattern 150, the upper electrode 160, and the mask 165. The capping film 170 is formed. The first capping layer is formed by performing an enhanced plasma chemical vapor deposition process at a first temperature of about 180 to 230 ° C. As an example, the first capping layer 170 may be a first silicon nitride layer.

Subsequently, a second capping layer 180 having a substantially uniform thickness is formed on the first capping layer. The second capping layer 180 is formed by performing an enhanced plasma chemical vapor deposition process at a temperature of about 380 to 420 ° C. which is a second temperature. As an example, the second capping layer 180 may be a second silicon nitride layer.

The second capping layer 180 of the present embodiment serves to relieve thermal stress generated in the upper electrode 160 and the phase change material layer pattern 150 in a subsequent process together with the first capping layer 170. . As a result, as shown in FIG. 1, the side of the phase change material film pattern may be prevented from being lost, and the upper electrode 160 and the phase change material film pattern may be prevented from being bent.

Subsequently, after the third insulating film 185 is formed on the resultant material, the upper electrode is formed through the third insulating film 185, the second capping film 180, the first capping film 170, and the mask 165. An upper contact electrode 190 is formed to be electrically connected to the upper contact electrode 190.

Subsequently, a metal material is deposited on the third insulating layer, and then an upper planarization process is performed to form a metal wiring 195 electrically connected to the upper contact electrode 190. As a result, a phase change memory device having a structure as shown in FIG. 2 is completed.

Since the phase change memory device manufactured by the method as described above includes the first capping film formed at the first temperature and the second capping film formed at the second temperature, the upper electrode and the image at the process temperature after the capping film are processed. The thermal stress applied to the changing material film pattern can be alleviated. Therefore, the sidewalls of the phase change material film pattern included in the phase change memory device may be prevented from being lost. In addition, since the upper electrode and the phase change material film pattern are not bent due to thermal stress, poor interface bonding characteristics between the upper electrode and the phase change material film pattern can be prevented.

As mentioned above, although preferred embodiment was described about this invention, this invention is not restrict | limited by this, The person of ordinary skill in the art to which this invention belongs is a deformation | transformation in the range which does not deviate from the essential characteristic of this invention. It will be appreciated that the present invention may be implemented in a modified form.

Claims (4)

Embedding a conductive material in an opening formed in the first insulating layer pattern to form a contact pad electrically connected to the substrate; Forming a lower contact electrode penetrating through the second insulating film pattern formed on the first insulating film pattern and electrically connected to the contact pad; Forming a phase change material film on the lower contact electrode and the second insulating film pattern; Forming an upper electrode film on the phase change material film; Applying a mask pattern to sequentially pattern the upper electrode layer and the phase change material layer to form a phase electrode and phase change material layer pattern; Forming a first capping film formed at a first temperature on the resultant; And And forming a second capping film formed on the first capping film at a second temperature higher than the first temperature. The method of claim 1, wherein the first temperature is 180 to 230 ° C., and the first capping layer is formed by performing an enhanced plasma chemical vapor deposition process and comprises silicon nitride. . The method of claim 1, wherein the second temperature is 380 to 420 ° C., and the second capping layer is formed by performing an enhanced plasma chemical vapor deposition process and comprises silicon nitride. . The method of claim 1, wherein after the forming of the second capping layer, Forming a third insulating film covering the second cap expansion film; Forming an upper contact electrode electrically connected to the upper electrode through the third insulating layer, the second capping layer, the first capping layer, and a mask; And And forming a metal wire electrically connected to the upper contact electrode.

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