JPH06310491A - Forming method for pattern on solid surface - Google Patents

Abstract

PURPOSE:To selectively activate or inactivate the surface of solid by applying an oxidizing beam in vacuum to the damage layer formed in a large area on a solid surface, thereby oxidizing the irradiated portion only in a pattern, and removing the resultant oxide layer by solution treatment. CONSTITUTION:The insulating film 12 on a semiconductor substrate 11 is subjected to dry etching to form a damaged layer 14. An oxidizing beam 16, for example, oxygen ion beam, is applied to a portion of the damaged layer 14 in a desired pattern. The semiconductor substrate 11 is exposed to a hydrofluoric acid atmosphere to dissolve and remove the fully oxidized area 17. As a result a surface region 18 without an oxide layer is formed in the beam- irradiated area; the damaged layer 14 or an oxide layer region formed thereon is left in the non-beam-irradiated areas. When Si epitaxial growth or W selective CVD is subsequently performed, therefore, selective growth occurs in the region 18 without an oxide film, and no growth is initiated in the damaged layer 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a solid surface, and more particularly to a method for patterning a solid surface used in an electronic device manufacturing process.

[0002]

2. Description of the Related Art Conventionally, a method of forming a pattern on a solid surface by performing a process using a mask on which a pattern is formed to form a pattern of an oxide film, a nitride film or a metal film has been generally used. It was Further, a method of selectively forming a film on a region other than the oxide film formed using a mask has also been used. As a method without using a mask, a method of directly processing the surface without using a mask with a laser beam or an electron beam has been used. Among the conventional methods, as a typical method of selectively forming a film in a region other than an oxide film formed using a mask, a method of selectively growing Si in a region other than an oxide film is By B. D. Joyce, et al., Nature, 1962, Volume 195, pp. 485-486, and directly processing the surface with a laser beam or electron beam without using a mask. As a typical method, a method of irradiating a solid surface with a laser beam in a Cr (CO) ₆ gas and selectively depositing Cr on the irradiated portion is
Reported by Morishige et al., Proc. Of the 26th Semiconductor / Integrated Circuit Symposium, Electrochemical Society, 1984, p.6.

[0003]

In the pattern forming method such as oxidation using a mask or the pattern forming method of selectively depositing a film on a region other than an oxide film formed using a mask, a fine pattern is formed. Is difficult to form, and
There is a drawback that the number of mask formation steps is required. Moreover, in the pattern formation method in which the surface is directly processed with a laser beam or an electron beam without using a mask, it is possible to form a fine pattern by selective etching or deposition in the irradiation part. However, there is a drawback in that it has no versatility that various selective processes can be performed for the irradiation unit and the whole other than the irradiation unit. An object of the present invention is to eliminate such drawbacks of the conventional solid surface pattern forming method, and selectively change and change the surface state of the area on the solid surface where pattern formation is desired or other area. It is an object of the present invention to provide a versatile solid surface pattern forming method capable of performing various selective reactions with respect to an entire region or other regions.

[0004]

A solid surface pattern forming method according to the first invention is to irradiate a damaged layer formed on a large area of a solid surface with an oxidative beam in a vacuum to expose only the irradiated portion. It is possible to form a pattern in a later step by sufficiently oxidizing and patterning, and then performing a solution treatment to selectively remove only the oxide layer of the irradiation portion to form an oxide film-free surface. And Here, the oxidizing beam is preferably an oxygen ion beam, an oxygen radical beam, an oxygen molecular beam, or an ozone molecular beam.

In the solid surface pattern forming method of the second invention, the damaged layer formed on a large area of the solid surface is irradiated with a laser, an electron beam or an ion beam in an oxidizing atmosphere or in water vapor, and only the irradiated portion is irradiated. Is sufficiently oxidized to perform patterning, and then solution treatment is performed to selectively remove only the oxide layer of the irradiated portion to form an oxide film-free surface, which enables pattern formation in a later step. Characterize. Here, examples of the oxidizing atmosphere include oxygen and ozone.

According to a third aspect of the present invention, there is provided a method for forming a pattern on a solid surface, which comprises irradiating an ion beam in a vacuum or a gas onto a large-area, non-damaged solid surface having a natural oxide film or a thin oxide film on the surface. A subsequent step by forming a damaged layer only on the irradiated part and patterning it, then performing a solution treatment, and selectively removing only the thin film on the surface of the region other than the irradiated part where there is no damaged layer to make it an active surface It is possible to form a pattern in.

[0007]

When the damage layer is formed in a wide area of the solid surface by dry etching or the like, the damage layer forms an insufficiently oxidized solid surface.
It cannot be easily dissolved and removed by a solution treatment such as hydrofluoric acid or a selective etching solution. On this damage layer,
In a vacuum, an oxidative beam such as an oxygen ion beam, an oxygen radical beam, an oxygen molecular beam or an ozone molecular beam is irradiated along a desired pattern, and only the irradiated portion is oxidized to form an oxidized pattern. Not only the pattern formation but also the insufficiently oxidized damage layer is dissolved and removed by the reaction with the solution when sufficiently oxidized by the oxidation process. When the beam-irradiated portion of the solid surface is sufficiently oxidized by the irradiation of the oxidizable beam onto the damaged layer of the present invention, only the sufficiently-oxidized portion is dissolved in the subsequent solution treatment or exposure to the atmosphere. The other areas are not removed by dissolution. As a result of this solution treatment, a pattern is formed in which the oxide film does not exist only in the beam-irradiated portion and the oxide film on the damaged layer exists in the other regions. When the next process atmosphere is applied to the surface of this pattern, the region where the oxide film on the damaged layer is removed has higher reactivity than the region having the oxide film on the damaged layer. Therefore, by selecting the process conditions, the reaction of the next process proceeds selectively in the region where the oxide film on the damaged layer is removed. As a result, it is possible to form a pattern in which the next process has advanced only in the region where the pattern has been formed by beam irradiation.

Second invention When a damage layer is formed on a wide area of the solid surface by dry etching or the like, the damage layer forms an insufficiently oxidized solid surface, and It cannot be easily dissolved and removed by a solution treatment with an acid or a selective etching solution. The damaged layer is irradiated with a laser, an electron beam, or an ion beam along a desired pattern in an oxidizing atmosphere such as oxygen, ozone, or water vapor, and only the irradiated portion is oxidized to form an oxidized pattern. When the irradiated portion is sufficiently oxidized by beam irradiation in an oxidizing atmosphere on the damaged layer, only the sufficiently oxidized portion is dissolved and removed in the subsequent solution treatment or exposure to the atmosphere, and the other regions Is not dissolved away. As a result of this solution treatment, a pattern is formed in which the oxide film does not exist only in the beam-irradiated portion and the oxide film on the damaged layer exists in the other regions.
As a result, similarly to the case of the first aspect of the invention, in the region where the oxide film on the damaged layer is removed, the reaction of the next process selectively progresses and pattern formation is performed.

Third invention When there is a large area of undamaged solid surface having a thin film such as a natural oxide film, there is no damage on this surface and it is not an insufficiently oxidized surface. To
It can be easily dissolved and removed by a solution treatment with hydrofluoric acid or a selective etching solution. An ion beam is irradiated onto this surface in a vacuum or gas along a desired pattern to form a damaged layer only on the irradiated portion. Subsequently, when solution treatment is performed, the oxide film in the region having no damaged layer other than the irradiated portion is removed. The damaged area of the irradiated portion is not dissolved and removed by solution treatment or exposure to the atmosphere, but remains selectively. As a result of this solution treatment, a pattern is formed in which the oxide film on the damaged layer exists only in the beam-irradiated portion and the oxide film does not exist in the other regions. The region where the oxide film is dissolved and removed has higher reactivity than the region having the oxide film on the damaged layer. When the next process atmosphere is applied to this surface, the region where the oxide film is removed and activated without the damage layer is more reactive than the region where the damaged layer is formed and the oxide film is insufficiently oxidized. It is highly likely. Therefore, by selecting the process conditions, the reaction of the next process proceeds selectively in the region without the oxide film. As a result, the next process does not proceed in only the area where the pattern is formed by the beam irradiation, and the pattern in which the process has advanced can be formed in the other areas.

In the present invention, the ion beam may be a focused ion beam. Further, the solution used in the solution treatment of the present invention and the atmosphere used for the atmosphere exposure may be of any type as long as the solution or the atmosphere can selectively etch the film on the surface. For oxide layers and natural oxide films,
Hydrofluoric acid or hydrofluoric acid vapor can be used.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the surface state on the damage layer formed by dry etching (FIG. 2A) in the first method of the present invention, and the hydrofluoric acid treatment is applied to the surface region where the damage layer is not irradiated with the oxygen molecule beam. XPS-Si showing the surface condition when applied (FIG. 2B) and the surface condition when the same hydrofluoric acid treatment was applied to the surface region where the damaged layer was irradiated with an oxygen molecular beam (FIG. 2C). It is a (2p) spectrum. In the figure, the binding energy is Bulk-S.
It is represented by a relative value to the i peak. In FIG. 2A, in addition to the peak indicating bulk Si, a peak indicating an incomplete Si oxide layer containing a dry etching gas component is observed. In FIG. 2B, which is an XPS-Si (2p) spectrum of a surface obtained by subjecting such a surface to hydrofluoric acid treatment without irradiating an oxygen molecular beam, in addition to the peak indicating bulk Si, Si oxide is shown. The peak is observed, which shows that the oxide layer is not removed even by the hydrofluoric acid treatment. On the other hand, in FIG. 2C, only the peak of bulk Si is observed, which shows that the damaged layer and the incomplete oxide layer formed on the damaged layer are removed. When the oxygen ion beam, the oxygen radical beam, or the ozone molecular beam is irradiated by the first method of the present invention, and the second method of the present invention
When a laser or the like is irradiated in an oxidizing atmosphere by the above method, the same difference in surface state is exhibited.

In the case where the damaged surface is irradiated with a focused ion beam to form a damaged layer only on the irradiated portion by the third method of the present invention, the irradiated portion is treated as shown in FIG. The surface state is the same, and the portion not irradiated is the surface state similar to FIG.

FIG. 1 is a sectional view of a sample showing changes in the solid surface for explaining an embodiment of a pattern forming method of the solid surface according to the first method of the present invention. In FIG. 1 (a),
In a semiconductor substrate 11, which is an example of a solid substrate, the insulating film 12 is etched by dry etching particles 13. A damaged layer 14 is formed by dry etching on the semiconductor surface exposed by etching the insulating film 12. The damaged layer 14 forms an incomplete oxide layer containing a dry etching gas component immediately after dry etching and an oxide film containing a large amount of incomplete suboxide which is not sufficiently oxidized after cleaning. In FIG. 1B, an oxidative beam (oxygen ion beam, oxygen radical beam, oxygen molecular beam or ozone molecular beam) 16 is applied to a region of the damaged layer 14 along a desired pattern in a vacuum. . Oxidation progresses in the irradiated portion to form the oxide layer region 17 in which the amount of sufficiently oxidized suboxide is small. During this beam irradiation, the substrate may be heated by the heating mechanism 15 to accelerate the oxidation. In FIG. 1C, the semiconductor substrate 11 is exposed to a liquid phase or vapor phase hydrofluoric acid atmosphere. By the reaction with hydrofluoric acid, the sufficiently oxidized region 17 is dissolved and removed. However, the damage layer 14 or the oxide layer formed on the damage layer is not easily dissolved and removed by the reaction with hydrofluoric acid, and the surface state does not change. Therefore, on the surface after the hydrofluoric acid treatment, there is a surface region 18 where there is no oxide layer in the beam irradiation portion, and there is a region of the damage layer 14 or an oxide layer formed on the damage layer other than the beam irradiation portion. Form a pattern. In FIG. 1D, the following process is performed on the pattern forming surface. For example, when epitaxial growth of Si or selective CVD of W is performed, growth selectively occurs on the region 18 where no oxide film exists and growth does not occur on the damaged layer 14. Therefore, the selectively grown material 19
Pattern can be formed. Further, as another process example, high selectivity etching such as wet etching may be used. In that case, only the region without the oxide layer is etched, and an etching pattern can be formed.

Here, when an oxidizing atmosphere such as oxygen, ozone, or water vapor is used instead of vacuum and a laser, an electron beam, or an ion beam is used instead of the oxidizing beam, the second method of the present invention is performed. Can be implemented.

FIG. 3 is a cross-sectional view of a sample showing changes in the solid surface for explaining an embodiment of the pattern forming method of the solid surface according to the third method of the present invention. In FIG. 3 (a),
The surface of the semiconductor substrate 11, which is an example of a solid substrate, has a thin film such as the natural oxide film 31. In FIG. 3B, this surface is irradiated with an ion beam 33 in a vacuum or a gas along a desired pattern. as a result,
The damaged layer 14 is formed on the irradiated portion. The damaged layer 14 forms an oxide layer having an incomplete structure / composition containing ions and components of an atmospheric gas immediately after ion irradiation, and an oxide film having an incomplete structure / composition containing a large amount of suboxide after cleaning. Since the part where ion irradiation is not performed does not change, the structure and composition of thin films such as natural oxide film do not change,
The fully oxidized sub-oxide remains on the surface as an oxide layer region with a small amount. In FIG. 3C, the semiconductor substrate 11 is exposed to a liquid phase or vapor phase hydrofluoric acid atmosphere. Due to the reaction with hydrofluoric acid, the thin film such as the natural oxide film 31 is dissolved and removed. However, the damaged layer 14, the oxide film having an incomplete structure and composition containing a large amount of ions and atmospheric gas components and a large amount of suboxide, is not easily dissolved and removed by the reaction with hydrofluoric acid, and the surface state is not changed. . Therefore, the surface after the hydrofluoric acid treatment has a region of the damaged layer 14 in the beam irradiation part and a region of the surface region 18 in which the oxide film does not exist other than the beam irradiation part, and a pattern is formed by these. In FIG. 3D, high selectivity etching such as wet etching is performed on the pattern formation surface of FIG. 3C. As a result, the region 18 where the oxide film does not exist
Are selectively etched, and no etching occurs on the damaged layer 14 including the oxide film. Therefore, only the region without the oxide layer can be selectively etched, and the pattern of the etched region 34 can be formed.
Further, in FIG. 3E, the following process is applied to the pattern forming surface of FIG. For example, when epitaxial growth of Si or selective CVD of W is performed, selective growth occurs on the region 18 where no oxide film exists,
No growth occurs on the damaged layer 14. Therefore, the pattern of the selectively grown material 19 can be formed.

[0016]

As described in detail above, according to the method of the present invention, the surface state of the region on the solid surface where pattern formation is desired or other region is selectively changed, and the changed region or other region is selected. It is possible to provide a general-purpose solid surface pattern forming method capable of performing various selective reactions with respect to the entire region. Therefore, by using the method of the present invention in an electronic device manufacturing process, it becomes possible to form a fine pattern or a pattern in which the surface condition is controlled, which can increase the versatility and the degree of freedom of the manufacturing process and improve the device performance. It has an effect that can greatly contribute to

[Brief description of drawings]

FIG. 1 is a sectional view of a sample for explaining an example of the present invention.

FIG. 2 is a diagram showing an XPS spectrum for explaining the effect of the present invention.

FIG. 3 is a sectional view of a sample for explaining an example of the present invention.

[Explanation of symbols]

 11 Semiconductor Substrate 12 Insulating Film 13 Dry Etching Particles 14 Damaged Layer 15 Heating Mechanism 16 Oxidizing Beam 17 Oxidized Layer Region Fully Oxidized Layer 18 No Oxide Film Existence Area 19 Selectively Grown Material 31 Natural Oxide Film 33 Ion Beam 34 Etched area

Claims (4)

[Claims] 1. A damaged layer formed on a large area of a solid surface is irradiated with an oxidizing beam in a vacuum to sufficiently oxidize only the irradiated portion for patterning, and then solution treatment is performed to perform the irradiation. A method for forming a solid surface pattern, which enables pattern formation in a later step by selectively removing only an oxide layer in a portion to form an oxide film-free surface. 2. The method for forming a solid surface pattern according to claim 1, wherein the oxidizing beam is an oxygen ion beam, an oxygen radical beam, an oxygen molecular beam or an ozone molecular beam. 3. A damaged layer formed on a large area of a solid surface is irradiated with a laser, an electron beam or an ion beam in an oxidizing atmosphere or in water vapor to sufficiently oxidize only the irradiated portion to perform patterning, A method for forming a solid surface pattern, which comprises performing a solution treatment and selectively removing only the oxide layer of the irradiated portion to form an oxide film-free surface, which enables pattern formation in a subsequent step. 4. A pattern is formed by irradiating an ion beam in a vacuum or a gas on a solid surface having a natural oxide film or a thin oxide film and having a large area without damage to form a damaged layer only on the irradiated portion. Then, a solution treatment is performed to selectively remove only the thin film on the surface of the region having no damaged layer other than the irradiated portion to form an active surface, which enables pattern formation in a subsequent step. Solid surface pattern forming method.