KR100308620B1 - Semiconductor fabrication equipment and method for fabricating capacitor by using the same - Google Patents

Abstract

PURPOSE: A semiconductor fabrication equipment and a method for fabricating a capacitor by using the same are provided to prevent reduction of a surface area of an HSG(HemiSpherical Grain) layer by performing a cleaning process after stabilizing the HSG layer. CONSTITUTION: A lower electrode layer is formed on a semiconductor substrate including an oxide layer and a nitride layer(S12). An HSG layer is formed on a surface of an exposed portion of the lower electrode(S14). A stabilization process of the HSG layer is performed to prevent unnecessary consumption of the HSG layer(S16). A cleaning process of the HSG layer is performed to remove pollutants or a natural oxide layer from the HSG layer(S18). A dielectric layer deposition process is performed to deposit a dielectric layer such as an NO layer on the HSG layer(S20). An upper electrode layer is formed by depositing a polysilicon on the dielectric layer and performing a photo etch process.

Description

Manufacturing equipment of semiconductor device and capacitor manufacturing method of semiconductor device using same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus and a method for manufacturing a capacitor of a semiconductor device using the same, and more particularly, to stabilize film quality characteristics of a HSG film formed to increase the surface area of a lower electrode of a capacitor. After performing the subsequent cleaning process, the semiconductor device manufacturing equipment and capacitor manufacturing method of the semiconductor device using the same can reduce the consumption of the HSG film during cleaning to reduce the capacitance of the capacitor due to the reduction of the surface area of the capacitor lower electrode It is about.

In recent years, as the semiconductor devices have been miniaturized and highly integrated, there has been a necessity to increase the capacitance of the capacitor, and in response to these requirements, the shape of the capacitor has become very complicated.

In a semiconductor memory device, a DRAM (Dynamic Random Access Memory) decreases in area of a unit memory cell composed of one transistor and one capacitor in a unit chip in proportion to an increase in memory capacity. However, even if the occupied area of the unit capacitor of the unit memory cell is reduced, the capacitance of the capacitor necessary for the accumulation of charge must be secured sufficiently. Therefore, various methods have been attempted to secure sufficient capacitance even if these occupation areas are reduced.

In the case of trench capacitors, they are dug deep into the semiconductor substrate to secure the desired capacitance. In the case of stack capacitors, the simple stacked structure leads to a high level of device structure. Capacities were secured by increasing the surface area of capacitors by changing to complex structures such as shapes and cylinders.

The memory capacity of the DRAM device is the lower electrode (or storage) electrode of the capacitor. In order to increase the memory capacity as the semiconductor device is highly integrated, various methods are proposed by combining the process of forming the lower electrode and subsequent processes thereof. It is becoming. For example, 1). A method of depositing a high dielectric film quality such as titanium nitride (TiN) and tantalum oxide (Ta2O3) after etching the polysilicon film forming the lower electrode, 2). There is a method such as a method of increasing the surface area of a capacitor by changing the etching form of the polysilicon film forming the lower electrode.

However, a method of increasing the surface area of a capacitor by using the characteristics of the material constituting the lower electrode without improving the dielectric film, improving the structure of the lower electrode, or the like as described in 1) or 2) has been proposed. That is, a method of increasing surface area by growing hemispherical grain (HSG), which is polycrystalline silicon having an uneven surface, is grown on the exposed surface of the lower electrode. One grain of HSG is about 500 to 1000 microns, and can typically double the capacitor capacity.

1 is a process flowchart showing a procedure of a capacitor manufacturing method of a semiconductor device by a conventional method.

As shown in FIG. 1, first, a contact hole is formed on a specific substructure made of an insulating film such as a nitride film or an oxide film on a semiconductor substrate, and then an amorphous silicon film is deposited, and then a lower portion of a semiconductor capacitor having a desired pattern is formed by a photolithography process. An electrode is formed (S2).

The lower electrode contacts the source region of the transistor through a contact hole and accumulates information according to the charge transferred from the source region, and an oxide film or the like formed on the semiconductor substrate is an interlayer insulating film.

Next, as a step (S4) to form an HSG film on the lower electrode, in the process of the state transition from amorphous silicon (a-Si) to polycrystalline silicon by the migration of the silicon in the state transition temperature region (Migration) It is a process that uses the phenomenon of forming the hemispherical form, which is the most stable form. Therefore, the HSG forming process is formed by, for example, low pressure chemical vapor deposition (LPCVD), which is a conventional chemical vapor deposition (Chemical Vapor Deposition). That is, the process chamber is maintained at about 550 ° C., and then Si2H6 or SiH4 gas, which is a silicon gas having a high surface reactivity, is injected to induce nucleation on the surface of the lower electrode, and then subjected to heat treatment. One hemispheric HSG is formed. In addition, after forming the HSG, phosphorus (Phosphorus) is diffused to convert to polysilicon. Therefore, the HSG has a surface area of about 2 to 3 times larger than the flat surface.

2 is a SEM photograph showing the surface state of the HSG formed on the surface of the lower electrode.

As shown in FIG. 2, the HSG surface shows a well-formed hemispherical grain.

The next step is to clean the semiconductor substrate on which the HSG film is formed (S6), and to remove the native oxide formed during the process. The natural oxide film has a low dielectric constant, which greatly reduces the capacitor capacity and may cause a defect in the subsequent formation of the dielectric film. The removal of the natural oxide film is usually performed by wet etching using SC-1 (Standard Chemical-1) cleaning solution.

FIG. 3 is an SEM photograph showing the surface state after washing the HSG shown in FIG. 2 with SC-1 for 10 minutes.

As shown in FIG. 3, the HSG surface state after the cleaning shows that the hemispherical protrusions of the HSG are significantly consumed, and the surface area thereof is significantly reduced than that shown in FIG. The surface area reduced at this time is about 50%.

The surface area reduction of the HSG was found to be proportional to the cleaning time. However, it was analyzed that shortening the cleaning time does not suppress the generation of impurities on the surface of the HSG. That is, when the cleaning time is shortened, uneven natural oxide film or other contaminants remaining on the surface of the HSG remain, resulting in an increase in the uniformity or resistance and stress between dielectric films to be deposited next, causing leakage current. Becomes

Next, as a step (S8) of forming a dielectric film, a NO (Nitride Oxide) film is deposited on the cleaned HSG film.

Next, in step S10 of forming an upper electrode, polysilicon is deposited on the dielectric layer to form an upper electrode.

In the conventional capacitor manufacturing method described above, the HSG surface is analyzed by SEM equipment after the cleaning process, which is a removal process of the natural oxide film after the deposition of the HSG. As shown in FIG. 3, the surface of the HSG is also consumed by the cleaning, resulting in a surface area. There is a problem that this is very reduced. In the HSG film formation process, the silicon moves to form hemispherical shape, and the amorphous silicon is transformed into crystallized silicon. At this time, the crystal structure does not have long range regularity and short range regularity. It is considered that the surface of the HSG is consumed by SC-1 together during the natural oxide film removal process by the cleaning chemical due to the unstable state.

This reduction in surface area due to the consumption of HSG counters the demand for sufficient capacitance, despite the reduction in the capacitor's footprint.

An object of the present invention is to solve the problems of the prior art to stabilize the film quality characteristics of the HSG film and then proceed with the HSG cleaning process to provide a method for producing a capacitor of a semiconductor device that the HSG surface area is not reduced even after the cleaning. There is.

Another object of the present invention is to provide a device for manufacturing a semiconductor device capable of stabilizing the film quality characteristics of the HSG film so that the HSG surface area is not reduced even after cleaning after the HSG forming process.

1 is a process flowchart showing a procedure of a capacitor manufacturing method of a semiconductor device by a conventional method.

Figure 2 is a SEM photograph showing the surface state of the HSG deposited on the lower electrode film by a conventional general technique.

3 is a SEM photograph showing the surface state after cleaning HSG deposited on the lower electrode film by SC-1 according to a conventional general technique.

Figure 4 is a schematic configuration diagram showing a process chamber in which the electron-emitting means according to an embodiment of the present invention.

5 is a process flowchart showing a procedure of a capacitor manufacturing method of a semiconductor device according to an embodiment of the present invention.

6 to 9 are process cross-sectional views illustrating a process according to the process flow chart of FIG.

FIG. 10 is a SEM photograph showing the surface state after the HSG is charged up and then cleaned with SC-1 according to one embodiment of the present invention. FIG.

* Explanation of symbols for main parts of the drawings

One ; Process chamber 2; Electron gun

4 ; Anode 6; Electro-optical Means

8 ; Deflection coil 10; chuck

20; Semiconductor substrate 22; Infrastructure

23; Contact hole 24; Oxide film

26; Lower electrode 28; HSG

30; Dielectric film 32; Upper electrode

According to another aspect of the present invention, there is provided a method of manufacturing a capacitor of a semiconductor device, the method including: (1) forming a lower electrode of a semiconductor capacitor on a semiconductor substrate on which a specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) stabilizing the HSG film such that the HSG film is consumed in a subsequent cleaning step so that its surface area is not reduced; And (4) cleaning the stabilized HSG film.

The stabilizing of the HSG film may be performed by performing an electron charge-up on the surface of the HSG film. In particular, the SEM (Scanning Electron Microsc opy) equipment may be subjected to an acceleration voltage of 1000 to 1500V and a filament current of 8 to 12A. It may be performed for about 5 to 20 minutes under the conditions.

In addition, the stabilizing of the HSG film may be performed by heat-treating the HSG film at a temperature higher than the process temperature for forming the HSG film, by irradiating the laser to the HSG film, or by applying a major to the HSG film. ) May be carried out by irradiation, or by implanting certain impurities into the HSG film.

On the other hand, one type of semiconductor device manufacturing equipment for achieving another object of the present invention, inside the process chamber that can perform the HSG film forming process on the lower electrode of the semiconductor capacitor, after the HSG film formation is completed In order to stabilize the HSG film, it is characterized in that an electron charge up means for scanning and charging up electrons is provided on the HSG film.

The electron charging up means includes: an electron gun for generating electrons; Electro-optical means for focusing electrons generated from the electron gun; And a deflection coil installed under the electro-optical means to adjust the direction of electrons focused by the electro-optical means.

On the other hand, another aspect of the manufacturing device of the semiconductor device for achieving another object of the present invention, the first process chamber capable of performing the HSG film forming process on the lower electrode of the semiconductor capacitor; A load lock chamber connected in vacuum to the first process chamber; And a second process chamber connected to the load lock chamber and provided with an electron charge-up means for scanning and charging up an electron to the HSG film to stabilize the HSG film after the formation of the HSG film is completed.

In addition, another aspect of the semiconductor device manufacturing equipment for achieving another object of the present invention, the first process chamber capable of performing the HSG film forming process on the lower electrode of the semiconductor capacitor; A load lock chamber connected in vacuum to the first process chamber; And a heat treatment chamber connected to the load lock chamber and capable of performing heat treatment on the HSG film at a temperature higher than the HSG film forming process temperature to stabilize the HSG film after the formation of the HSG film is completed.

The present invention stabilizes the deposited HSG film to increase the surface area of the capacitor lower electrode of the semiconductor device, thereby preventing the HSG film from being consumed by the cleaning liquid and reducing its surface area after a subsequent cleaning step, thereby reducing the capacitance of the capacitor. The present invention relates to a semiconductor device manufacturing apparatus for improving and a capacitor manufacturing method for a semiconductor device using the same.

The conventional HSG film formation process has been proposed by Watanabe et al. In Japan, and is referred to as 'Hemispherical Grained Silicon Formation on In-situ Porous Doped Amorphous -Si Using the Seeding Method' (SSDM '92, PP.422-424.H.Watan abe. et al.) is a process using the phenomenon of forming a hemispherical region where the surface energy is the most stable form by the migration of silicon in the temperature range of the crystal and amorphous state of silicon. Therefore, the HSG process is characterized in that the highly reactive silicon gas (Si2H6, SiH4) or silicon present in the lower electrode material supplied into the process chamber protrudes from the structural abnormality of the wafer surface or with some deposited particles as seeds. It forms hemispherical shape with irregular shape. At this time, it is considered that the crystal structure does not have long range regularity and has short range regularity as the amorphous structure is transferred to the crystal structure. It is shown by the chemical that the protruding surfaces of the HSG are consumed together by SC-1.

In order to stabilize the HSG film, in the present invention, constant energy is supplied to the surface of the HSG whose crystal state is unstable through an electron charge up or heat treatment.

Hereinafter, with reference to the accompanying drawings a specific embodiment of the present invention will be described in detail.

FIG. 4 is a schematic diagram illustrating a process chamber in which an electron-emitting means for performing an electron charge up on a surface of an HSG film is a semiconductor device manufacturing apparatus according to an embodiment of the present invention. The electron-emitting means has the same basic configuration as a general SEM (Secondary Electron Microscopy) equipment and may be used as it is.

As shown in FIG. 4, an electron gun 2 emitting electrons in the upper part of the process chamber 1, an anode 4 for accelerating the emitted electrons, and a semiconductor substrate of electrons accelerated by the anode 4 are reached. Electro-optical means 6 for determining the spot area of electrons to be used, deflection coil 8 for determining the direction of spot on the semiconductor substrate of electrons, and chuck 10 to which the semiconductor substrate is mounted. do.

The process chamber 1 equipped with the electron-emitting means used a process chamber capable of performing a chemical vapor deposition process capable of performing a general HSG film forming process.

However, the process chamber 1 in which the electron emitting means is installed may be formed as a semiconductor device manufacturing equipment independent of the process chamber capable of performing the HSG film forming process, and the process in which the electron emitting means is installed. The chamber 1 may be formed via a process chamber of a chemical vapor deposition apparatus capable of performing an HSG film forming process and a load lock chamber in a vacuum state.

As another method of stabilizing the HSG film, the same or separate process chamber as the process chamber for forming the HSG film is installed even when the surface of the HSG film is heat treated, or the laser treatment, the major treatment, or the implantation of impurities are performed. It can also be done.

5 is a process flowchart showing a procedure of a capacitor manufacturing method of a semiconductor device according to an embodiment of the present invention.

As shown in FIG. 5, a step (S12) of forming a lower electrode film of a semiconductor capacitor on a semiconductor substrate having a lower structure consisting of an oxide film or a nitride film is performed first, after forming a contact hole on the lower structure on the semiconductor substrate. An amorphous silicon film is deposited on the entire surface of the semiconductor substrate including the contact hole, and a lower electrode pattern is formed by performing a general photo process and an etching process.

Next, as a step (S14) to form an HSG film on the exposed surface of the lower electrode, a model name ANELVA SRE-2100, a low pressure chemical vapor deposition equipment was used. The HSG film forming process is to form a hemispherical region in which the surface energy is most stable by the migration of silicon in the temperature region in which the amorphous silicon transitions to the crystalline state, as described above. It is performed while supplying silicon gas (Si2H6, SiH4) having strong surface reactivity to the inside, and generally, a film is formed in a temperature range of 550 ° C to 640 ° C.

The following is to prevent the exhaustion of the HSG film during the subsequent cleaning step by stabilizing the HSG film (S16). As a method of stabilizing such an HSG film, the surface of the HSG film may be charged up or heat treated as described above. In addition, the surface of the HSG film may be performed by irradiating a laser or a major, or may be performed by implanting predetermined impurities.

Next, the step of cleaning the HSG film (S18), after the HSG film forming process before the dielectric film forming process to remove the natural oxide film formed on the HSG film or to remove contaminants. This is because the natural oxide film has a low dielectric constant, which greatly reduces the capacitor capacity. The removal of the natural oxide film is performed by wet etching using a SC-1 (Standard Chemical-1) cleaning solution. Process time is about 10 minutes.

Next, as a step (S20) of forming a dielectric film, a dielectric film, such as a NO film, is deposited on the HSG film after the cleaning process is completed.

Next, as a step (S22) of forming the upper electrode film, after depositing polysilicon on the dielectric film, a conventional photolithography process is formed to form an upper electrode having a desired pattern to complete the capacitor.

6 through 9 are cross-sectional views illustrating a process of forming a semiconductor capacitor according to the process flowchart of FIG. 5.

FIG. 6 shows that the lower electrode 26 is formed on the semiconductor substrate 20 having the specific substructure 22 including the nitride film or the like that insulates a specific conductive film pattern (not shown) and the oxide film 24. It is a cross section. The lower electrode 26 contacts the source region of the semiconductor substrate 20 constituting the transistor through the contact hole 23 and accumulates information according to the charge transferred from the source region. The lower structure 22 and the oxide film 24 formed on the () are used as the interlayer insulating film. Therefore, first, an oxide film 24 used as an interlayer insulating film is formed on the semiconductor substrate 20 having the lower structure 22, and then the lower electrode 26 of the capacitor is connected to the semiconductor substrate 20 through a photolithography process. The contact hole 23 is formed in the portion to be contacted. Next, amorphous silicon (amorphous silicon) constituting the lower electrode 26 is deposited on the entire surface of the semiconductor substrate 20 including the contact hole 23 by chemical vapor deposition to form the lower electrode 26 through a photolithography process. To form. The shape and structure of the lower electrode 26 may be various.

FIG. 7 is a sectional view showing that an HSG film 28 is formed on the lower electrode 26. As shown in FIG.

The HSG 28 has a hemispherical shape in which the surface energy is most stable by migration of silicon in the state transition temperature region in the process of state transition from amorphous silicon (a-Si) to polysilicon. It is a process using the phenomenon formed. The HSG 28 film has a surface area of two to three times that of a flat surface.

The HSG 28 is formed by low pressure chemical vapor deposition. That is, the process chamber is maintained at a temperature of 550 ° C. to 640 ° C., for example, at 550 ° C. and 1 Torr, and then Si 2 H 6, or SiH 4 gas, which is a highly reactive silicon gas, is injected into the nucleus on the lower electrode 26 surface. After the production is induced, heat treatment is performed to form an HSG 28 film having a roughly hemispherical surface by thermal movement of silicon around the nucleus. In addition, when HSG 28 is formed, impurities such as phosphorous may be diffused. Next, the HSG film 28 is stabilized so that the HSG 28 film is not consumed in the subsequent cleaning step of the semiconductor substrate 20 on which the HSG 28 film is formed.

At this time, in order to stabilize the HSG film 28, the semiconductor substrate is moved to the SEM equipment, and the HSG 28 film is then charged up. When the electron emission means is formed in the above-described HSG film formation chamber, the electron charge can be applied to the surface immediately after the HSG film 28 is formed.

The process conditions of the electron charge up in the process chamber equipped with the SEM device disclosed in FIG. 4 are about 5 to 20 minutes at an acceleration voltage of 1000 to 1500 V and a filament current of 8 to 12 A of electrons generated in the SEM device. Preferably it is carried out under an acceleration voltage of 1300V current 10A.

In the next process, the native oxide film (not shown) formed on the surface of the HSG 28 is removed by wet etching using an SC-1 cleaning solution. The natural oxide film has a fatal effect on the capacitance increase of the capacitor. That is, since the dielectric constant is small, the capacitance of the capacitor is reduced and process defects are caused when the dielectric film 30 of FIG. 8 is deposited.

Fig. 10 is a SEM photograph showing the surface state of the HSG 28 film after being charged up with electrons and then cleaned with SC-1. As shown in the SEM photograph of FIG. 10, the surface of the HSG 28 film after the cleaning shows the same surface condition as before the cleaning. Therefore, the surface area reduction after cleaning does not appear as in the prior art, which contributes to an increase in the capacitance of the capacitor. The surface state of the HSG film charged up the electrons shows a constant state regardless of the cleaning time.

8 is a cross-sectional view showing a state in which a dielectric film 30 is deposited on the HSG 28 film. A nitride film is formed on the surface of the HSG 28 by a conventional method, and then the NO dielectric film 30 is formed by dry or wet oxidation of the nitride film surface.

9 is a cross-sectional view showing the deposition of the upper electrode 32 on the dielectric film.

The capacitor is formed by depositing a doped polysilicon film on the NO dielectric film 30 to form an upper electrode 32.

Therefore, according to the present invention, after forming the HSG film as described above, before performing the cleaning process, the surface of the HSG film is stabilized to prevent the HSG film from being consumed during the subsequent cleaning process, thereby sufficiently maintaining the desired capacitance. It works.

Therefore, the HSG is also prevented from being consumed at the time of cleaning, so that the desired capacitance of the capacitor can be sufficiently secured.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (13)

(1) forming a lower electrode of the semiconductor capacitor on the semiconductor substrate on which the specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) stabilizing the surface of the HSG film by electron charge up so that the HSG film is consumed in a subsequent cleaning step and the surface area thereof is not reduced; And (4) cleaning the stabilized HSG film. The method of claim 1, wherein the HSG film is formed using a low pressure chemical vapor deposition (LPCVD) method, and the cleaning after the charge up of the HSG film is performed using a Standard Chemical-1 (SC-1) cleaning solution. Capacitor manufacturing method of the semiconductor device. The method of claim 1, wherein the surface of the HSG film is charged up by using an SEM (Scanning Electron Microscopy) device. 4. The method of claim 3, wherein the process conditions of the SEM equipment for performing the electron charge up are an acceleration voltage of 1000 to 1500V and a filament current of 8 to 12A. The method of claim 4, wherein the process time for performing the electron charge up is 5 minutes to 20 minutes. (1) forming a lower electrode of the semiconductor capacitor on the semiconductor substrate on which the specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) stabilizing the HSG film at a temperature higher than the process temperature for forming the HSG film so that the HSG film is consumed in a subsequent cleaning step so that its surface area is not reduced; And (4) cleaning the stabilized HSG film. (1) forming a lower electrode of the semiconductor capacitor on the semiconductor substrate on which the specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) a laser on the HSG film so that the HSG film is consumed during a subsequent cleaning step and the surface area thereof is not reduced. Irradiation) to stabilize; And (4) cleaning the stabilized HSG film; Capacitor manufacturing method of a semiconductor device comprising the. (1) forming a lower electrode of the semiconductor capacitor on the semiconductor substrate on which the specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) stabilizing the HSG film by irradiating a major so that the HSG film is consumed in a subsequent cleaning step and the surface area thereof is not reduced; And (4) cleaning the stabilized HSG film. (1) forming a lower electrode of the semiconductor capacitor on the semiconductor substrate on which the specific substructure is formed; (2) forming a HSG (Hemi-Spherical Grained) film on the exposed surface of the lower electrode; (3) stabilizing by implanting a specific impurity on the HSG film so that the HSG film is consumed in a subsequent cleaning step so that its surface area is not reduced; And (4) cleaning the stabilized HSG film. In the process chamber capable of performing the HSG film forming process on the lower electrode of the semiconductor capacitor, an electron charge charge-up that can be charged up by scanning the electron to the HSG film to stabilize the HSG film after the formation of the HSG film is completed. Semiconductor device manufacturing equipment, characterized in that the means is provided. 13. The apparatus of claim 12, wherein the electron charge up means comprises: an electron gun for generating electrons; Electro-optical means for focusing electrons generated from the electron gun; And a deflection coil installed under the electro-optical means to adjust the direction of electrons focused by the electro-optical means. The semiconductor device manufacturing equipment, characterized in that consisting of. A first process chamber capable of performing an HSG film forming process on the lower electrode of the semiconductor capacitor; A load lock chamber connected in vacuum to the first process chamber; And a second process chamber connected to the load lock chamber and provided with an electron charge up means for scanning and charging up an electron to the HSG film to stabilize the HSG film after the formation of the HSG film is completed. Semiconductor device manufacturing equipment, characterized in that consisting of. A first process chamber capable of performing an HSG film forming process on the lower electrode of the semiconductor capacitor; A load lock chamber connected in vacuum to the first process chamber; And a heat treatment chamber connected to the load lock chamber and configured to heat-treat the HSG film at a temperature higher than the HSG film forming process temperature to stabilize the HSG film after the HSG film is formed. Semiconductor device manufacturing equipment, characterized in that consisting of.