JPH11289063A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device for improving reliability or yield by preventing the generation of a particle cansing a problem on a micro-processing and for increasing a capacitor capacity in a low temperature process. SOLUTION: In this method for manufacturing a semiconductor device, an insulating film 11 is accumulated by the oxidation of an organic compound containing silicon on a substrate, an opening 12 is formed in the insulating film 11, the surface of the insulating film is turned into a rough face 13 by operating a chemical processing, a conductive film 14 is formed on the whole face, the conducive film other than the conductive film formed inside the opening is removed, the conductive film 14 is buried into the opening, and the insulating film 11 is removed. Also, an organic compound containing silicon is obtained as an organic silane, oxidation is attained as oxidation by atmosphere containing ozone, and the chemical processing is attained as exposure to atmosphere containing hydrogen fluoride as main components. Also, the removal of the conductive film other than the conductive film formed inside the opening is operated by mechanical/chemical grinding or etch-back.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device having a rough electrode surface for improving the storage capacity of a capacitor for storing charge in a semiconductor memory.

[0002]

2. Description of the Related Art DR widely used in the field of information equipment
An AM (randomly read / write memory that requires a storage holding operation) stores information by holding charges by a capacitor. In reading data in a DRAM, the charge stored in a capacitor is connected to a bit line through a switch of a transistor, and a change in the potential of the bit line due to the outflow of charge is amplified by a differential amplifier and read as data.

However, since the charge stored in the capacitor decreases with time, the DRAM periodically performs a refresh operation of reading and rewriting the charge of the capacitor. DR from this
In the AM, the capacitance of the capacitor must be increased as much as possible in order to improve the reliability of data reading, prevent soft errors, and reduce the number of periodic refresh operations in view of low power consumption. However, with an increase in memory capacity and high-density integration due to miniaturization, the area occupied by a capacitor in a chip has become smaller and smaller, and it has become difficult to increase the charge storage capacity of the capacitor. For this reason, the problems of the data hold time and the soft error have become remarkable. To avoid this problem, an HSG structure (Hemisphere) is used as a technique for increasing the capacity without increasing the occupied area of the capacitor.
ical grain structure) has begun to be used. H
The SG structure is intended to increase the area of the electrode surface by roughening the electrode surface of the capacitor, thereby increasing the capacitance of the capacitor.

FIG. 3 shows a process of manufacturing a capacitor having a general HSG structure. In FIG. 3, first, a contact hole 31 is opened in a base insulating film 30, and then a lower electrode 32 of the capacitor is formed of polysilicon.
2 is deposited on the amorphous silicon 33 (FIG. 3).
(A)). Next, when a heat treatment at 600 to 700 ° C. is applied in this state, the amorphous silicon 33 is polycrystallized by solid phase growth, and the lower electrode 3 having a hemispherical uneven surface is formed.
2 '(FIG. 3 (B)). Since the crystal grains of polycrystalline silicon are also formed in a region other than the lower electrode 32 'of the capacitor, they are removed by etch-back (FIG. 3).
(C)). Then, a capacitor insulating film 33 and an upper electrode 34 of a polysilicon film are sequentially deposited to form an HS electrode as shown in FIG.
A capacitor having a G structure is obtained. As is clear from FIG. 3D, a capacitor having the upper electrode 34 and the lower electrode 32 'having a large surface area with unevenness and having a large surface area can be manufactured, and the structure has an increased capacity.

[0005]

However, in this manufacturing method, the unevenness of the formed rough surface is granular polysilicon, so that it is easily peeled off in the course of the process step, which causes particles to cause the reliability and the reliability of the product. There is a problem of lowering the yield. In addition, if the etch-back conditions are not appropriate, polysilicon may remain in unnecessary parts and cause a short circuit. Further, a high-temperature heat treatment of about 600 to 700 ° C. is required during the solid phase growth of the amorphous silicon 33. However, as the dimensions are miniaturized, the diffusion of the diffusion layer in the lateral direction due to this heat treatment affects the electrical characteristics. The effects cannot be ignored. That is, formation of a shallow junction necessary for preventing a short channel effect and an increase in junction resistance is hindered. Therefore, it is indispensable for miniaturization to avoid the high temperature process as described above.

The present invention solves the above-mentioned conventional problems, and can prevent the generation of particles which are a problem in the miniaturization process, thereby increasing the reliability and yield, and increasing the capacitance of the capacitor in a low-temperature process. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can be performed.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: depositing an insulating film on a substrate by oxidizing an organic compound containing silicon; forming an opening in the insulating film; A conductive film is formed over the entire surface, a conductive film is formed over the entire surface, a portion of the conductive film other than the conductive film formed inside the opening is removed, the conductive film is buried in the opening, and the insulating film is removed.

The organic compound containing silicon is organic silane, the oxidation is oxidation in an atmosphere containing ozone, and the chemical treatment is exposure to an atmosphere containing hydrogen fluoride as a main component. In addition, removal of the conductive film other than the conductive film formed inside the opening is performed by mechanical chemical polishing or etch back. According to the method of manufacturing a semiconductor device according to claim 1, the surface of the insulating film deposited by oxidizing an organic compound containing silicon is exposed to an atmosphere containing hydrogen fluoride as a main component, so that the surface has irregularities. It can be a rough surface. If a conductive film is formed on this rough surface, the conductive film will have the transferred irregularities. The irregularities on the conductive film thus formed do not generate particles due to peeling off, unlike the granular polysilicon formed by the solid phase growth of amorphous silicon. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. further,
Since the solid phase reaction is not performed, the capacity of the capacitor can be increased by a low temperature process.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device.
A conductive film is formed on a substrate, the conductive film is selectively removed, an insulating film is deposited on the surface of the conductive film by oxidation of an organic compound containing silicon, and a chemical treatment is performed on the insulating film surface to roughen the surface. The surface portion of the insulating film and the conductive film are simultaneously etched to transfer a rough surface shape to the conductive film and to remove the insulating film.

The organic compound containing silicon is organic silane, the oxidation is oxidation in an atmosphere containing ozone, and the chemical treatment is exposure to an atmosphere containing hydrogen fluoride as a main component. The etching of the surface portions of the insulating film and the conductive film is performed by isotropic etching. According to the method of manufacturing a semiconductor device according to claim 2, by exposing the surface of the insulating film deposited by oxidizing an organic compound containing silicon on the surface of the conductive film to an atmosphere containing hydrogen fluoride as a main component, The surface can be roughened with irregularities. By etching the surface portions of the insulating film and the conductive film at the same time, the rough surface shape is transferred to the conductive film. The irregularities on the conductive film thus formed do not generate particles due to peeling off, unlike the granular polysilicon formed by the solid phase growth of amorphous silicon. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. Further, since no solid-phase reaction is performed, the capacitance of the capacitor can be increased by a low-temperature process.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a cross-sectional view showing a manufacturing process of a capacitor portion for explaining a method of manufacturing a semiconductor device according to a first embodiment of the present invention. In FIG. 1A, reference numeral 10 denotes a base insulating film formed on a semiconductor substrate, reference numeral 11 denotes an insulating film for forming a shape of a lower electrode of a capacitor, and contact holes (contact holes) in the base insulating film 10 and the insulating film 11. (Opening) 12 is formed. In the next step (FIG. 1B), the insulating film 11
The insulating film 11 is made of tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) vaporized by bubbling with nitrogen at 65 ° C. at a nitrogen flow rate of 1.8 S so that the surface of the insulating film 11 is roughened.
LM and 7.5S oxygen containing 20g / Nm ³ ozone
LM and a mixed gas of nitrogen 1.0 SLM as a main raw material,
TEOS formed by thermal decomposition reaction at a deposition temperature of 410 ° C
It is formed by a film. The SLM is in a standard state (1 atm,
20 / ° C.) and g / N
m ³ also indicates g / m ³ under standard conditions (1 atm, 20 ° C.).

An insulating film (TEO) deposited under these conditions
In S film 11, the following was found from experiments.
In the formation of the insulating film (TEOS film) 11, the amount of ozone is formed at 100 g / Nm ³ and 20 g / Nm ³ ,
When etching was performed using gas-phase hydrogen fluoride and the surface state was observed, a flat surface was observed when the amount of ozone was 100 g / Nm ³ . On the other hand, the ozone amount is 20 g / Nm ³
In the case of the above, irregularities of about 0.06 μm were generated.

[0013] Such a phenomenon is considered as follows when viewed at the molecular level. When oxygen having a low ozone content is used for growing the insulating film (TEOS film) 11, a film is formed in which the moisture is surrounded by by-products mainly composed of long chain silicon. When such a film is exposed to gas-phase hydrogen fluoride (hereinafter referred to as HF vapor), it is considered that the surface is roughened due to the release of the water from the film. After all, the insulating film (TEOS) used in this embodiment is used.
The film (film) 11 has the property of becoming a rough surface state when exposed to HF vapor, and the present invention utilizes such a novel phenomenon.

FIG. 1B shows an insulating film (TEOS film) 11.
Is a step of exposing the surface of the insulating film (TEOS film) 11 to a rough surface 13 in order to make the surface of the insulating film (TEOS film) 11 rough. FIG. 1C shows a step of depositing polysilicon to be a lower electrode (conductive film) 14 of the capacitor on the entire surface. Since the lower electrode 14 is formed on the insulating film (TEOS film) 11 which is the rough surface 13, the lower boundary is uneven. FIG. 1D shows a portion of the lower electrode 14 of polysilicon deposited in FIG. 1C other than the lower electrode 14 formed inside the contact hole 12 and the lower electrode 14 is formed in the contact hole 12. This is a step of etching back the deposited polysilicon by plasma etching in order to embed in a concave shape. This is also possible by mechanical chemical polishing. FIG. 1E shows an insulating film (TEOS film) for exposing the uneven surface of the lower electrode 14.
This is a step of removing 11. Insulating film (TEOS film) 11
Is removed by a hydrogen fluoride solution. Insulating film (TEO
After the removal of the (S film) 11, the surface of the lower electrode 14 appears as an uneven rough surface 15. FIG. 1F shows an oxide film, a silicon nitride film, and an oxide film (ONO film) to be a capacitor insulating film 16 deposited on a lower electrode 14 having a rough surface. This is a deposition step.
Through these steps, a capacitor structure with an increased electrode surface area is completed.

According to the method of manufacturing a semiconductor device having the above-described structure, the rough surface 15 is formed by transferring the irregularities on the surface of the insulating film (TEOS film) 11 to the lower electrode 14, so that the conventional amorphous silicon Unlike granular polysilicon formed by solid phase growth, no particles are generated due to peeling off. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. Further, since no solid-phase reaction is performed, the capacitance of the capacitor can be increased by a low-temperature process.

As the miniaturization further progresses in the future, a high dielectric constant film or a ferroelectric film is used instead of the ONO film as a capacitance insulating film in order to form a capacitor having a sufficient capacitance in a finer region. However, it is necessary to use a metal film of Ru, TiN, W, Pt or the like instead of the upper electrode 17 to increase the capacity. Conventional H
The method of manufacturing a semiconductor device having an SG structure is a technique utilizing the property that amorphous silicon becomes granular by a solid-phase reaction due to heat. However, according to the present invention, the unevenness of the surface of the capacitor electrode is made of metal other than silicon. It can be formed.

Second Embodiment FIG. 2 is a cross-sectional view illustrating a manufacturing process of a capacitor portion for explaining a method of manufacturing a semiconductor device according to a second embodiment of the present invention. FIG. 2A shows a step of forming a lower electrode of the capacitor. After depositing polysilicon to be a lower electrode (conductive film) 22 on a base insulating film 20 in which a contact hole 21 is opened, a step of selectively forming the lower electrode is performed. A convex shape is formed by etching. In FIG. 2B, a thin insulating film (TEO) is formed on the lower electrode 22 under the same conditions as those formed in the first embodiment.
(S film) 23 is deposited. In FIG. 2C, the insulating film (TE
70 to 80 in order to make the surface of the OS film) 23 rough
Exposure to HF vapours. In FIG. 2D, the insulating film (T
In order to transfer the concavo-convex shape of the (EOS film) 23 to polysilicon serving as the lower electrode 22, dry etching using a mixed gas of Cl ₂ , HBr, He, and O ₂ is performed from above the insulating film (TEOS film) 23. ing. Under this etching condition, the selectivity of the etching rate between the insulating film (TEOS film) 23 and the lower electrode 22 is low, so that the unevenness of the insulating film (TEOS film) 23 is transferred to the polysilicon of the lower electrode 22 and the rough surface 25 is formed. Become. In FIG. 2E, an ONO film serving as a capacitance insulating film 26 is deposited on the lower electrode 22 having a roughened surface, and polysilicon serving as an upper electrode 27 is further deposited. Through these steps, a capacitor structure with an increased electrode surface area is completed.

According to the method of manufacturing a semiconductor device thus configured, the surface of the insulating film deposited on the surface of the conductive film by oxidation of an organic compound containing silicon is exposed to an atmosphere containing hydrogen fluoride as a main component. By doing so, the surface can be made a rough surface having irregularities. By etching the surface portions of the insulating film and the conductive film at the same time, the rough surface shape is transferred to the conductive film. The irregularities on the conductive film thus formed do not generate particles due to peeling off, unlike the granular polysilicon formed by the solid phase growth of amorphous silicon. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. further,
Since the solid phase reaction is not performed, the capacity of the capacitor can be increased by a low temperature process.

Although polysilicon is used for the capacitor electrode in the second embodiment, even when the capacitor electrode is formed of a metal film as in the first embodiment, Ru,
The present invention can be applied by using a condition in which the etching selectivity between a metal film such as TiN, W, and Pt and a TEOS film is small. In the first and second embodiments, TMOS [SiC ₄ H ₁₂ O ₄ ], OMCTS [Si ₄
C ₈ H ₂₄ O ₄ ], TMCTS [Si ₄ C ₄ H ₁₆ O ₄ ],
SOBC [((CH ₃ ) ₃ SiO ₂ ) B], SOP
[(CH ₃ ) ₃ SiO) ₃ PO], DADBS [SiC
₁₂ H ₂₄ O _6] the same effect be used is obtained.

[0020]

According to the method of manufacturing a semiconductor device according to the first aspect, the surface of the insulating film deposited by oxidizing an organic compound containing silicon is exposed to an atmosphere containing hydrogen fluoride as a main component. The surface can be roughened with irregularities. If a conductive film is formed on this rough surface, the conductive film will have the transferred irregularities. The irregularities on the conductive film thus formed do not generate particles due to peeling off, unlike the granular polysilicon formed by the solid phase growth of amorphous silicon. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. Further, since no solid-phase reaction is performed, the capacitance of the capacitor can be increased by a low-temperature process.

According to the second aspect of the present invention, the surface of the insulating film deposited on the surface of the conductive film by oxidation of the organic compound containing silicon is exposed to an atmosphere containing hydrogen fluoride as a main component. Thus, the surface can be made a rough surface having irregularities. By etching the surface portions of the insulating film and the conductive film at the same time, the rough surface shape is transferred to the conductive film. The irregularities on the conductive film thus formed do not generate particles due to peeling off, unlike the granular polysilicon formed by the solid phase growth of amorphous silicon. In addition, since there is no step of removing crystal grains by etch back, no granular polysilicon remains, and reliability and yield are increased. Further, since no solid-phase reaction is performed, the capacitance of the capacitor can be increased by a low-temperature process.

Furthermore, as the miniaturization of semiconductor integrated circuits progresses in the future, it is highly likely that it will be necessary to replace the electrode material of the capacitor with a material other than silicon, such as metal. At this time, by using the method for manufacturing a semiconductor device of the present invention, it is possible to roughen the electrode surface without limiting the material to be the electrode.

[Brief description of the drawings]

FIG. 1 is a process sectional view of a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a process sectional view of a method for manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 3 is a process sectional view of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Insulating film (TEOS film) 12 Contact hole (opening) 13, 15 Rough surface 14 Lower electrode (polysilicon conductive film) 16 Capacitive insulating film (ONO film) 17 Upper electrode (polysilicon film) 22 Lower electrode (polysilicon) 23) Insulating film (TEOS film) 24, 25 Rough surface 26 Capacitive insulating film (ONO film) 27 Upper electrode (polysilicon film)

Claims (5)

[Claims] A step of depositing an insulating film on a substrate by oxidizing an organic compound containing silicon, a step of providing an opening in the insulating film, and a step of performing a chemical treatment on the surface of the insulating film to roughen the surface. Forming a conductive film on the entire surface, removing the conductive film in a portion other than the conductive film formed inside the opening to bury the conductive film in the opening, and removing the insulating film A method for manufacturing a semiconductor device, comprising: 2. A step of forming a conductive film on a substrate, a step of selectively removing the conductive film, and a step of depositing an insulating film on a surface of the conductive film by oxidizing an organic compound containing silicon. A step of performing a chemical treatment on the surface of the insulating film to roughen the surface, and simultaneously etching a surface portion of the insulating film and the conductive film to transfer the shape of the rough surface to the conductive film and remove the insulating film And a method of manufacturing a semiconductor device. 3. The method according to claim 1, wherein the organic compound containing silicon is organic silane, the oxidation is oxidation in an atmosphere containing ozone, and the chemical treatment is exposure to an atmosphere containing hydrogen fluoride as a main component. Of manufacturing a semiconductor device. 4. The method according to claim 1, wherein the step of removing the conductive film other than the conductive film formed inside the opening is performed by mechanical chemical polishing or etch back. . 5. The method for manufacturing a semiconductor device according to claim 2, wherein the surface portions of the insulating film and the conductive film are etched by isotropic etching.