JP4704595B2 - Method of growing fine three-dimensional structure by CVD and focused ion beam apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for forming an ultrafine three-dimensional structure by a CVD method in which a focused ion beam is irradiated while a source gas is blown onto a sample surface.
[0002]
[Prior art]
Ultra-fine three-dimensional structures are highly needed in a wide range of fields, such as knives, drills, manipulator probes, spring coils, probe microscope probes, and coils for fine electronic circuits, which are used in the processing of microscope samples. There are great expectations for the provision. Conventionally, it has been attempted to manufacture such a superfine three-dimensional structure by forming a material such as a block by mechanical processing and then scraping the material by a sputter etching method. However, this method is relatively easy if the workpiece is a linear shape such as a manipulator probe or a probe microscope stylus, but it is extremely difficult to process a three-dimensional shape such as a drill or a coil. In particular, when the shape is complicated, such as a U-turn shape in the vertical direction, no correspondence can be obtained.
In addition to the above-mentioned sputtering etching method, gas processing etching method, chemical etching method, etc., as well as processing for removing materials, the CVD method (chemical vapor deposition method) is used as a microfabrication technology for semiconductor devices and masks used in the manufacture of semiconductor devices. Processing to attach the material called has been used. Therefore, researchers have attempted to develop a technique for forming an ultrafine three-dimensional structure by this CVD method. This CVD method includes a method using a laser beam, a method using a focused electron beam, and a method using a focused ion beam. In the deposition by the CVD method, since the dimension of a member to be deposited depends on the beam diameter, it is required that the beam diameter is small in order to manufacture this kind of ultrafine three-dimensional structure. In the case of using laser light, the beam diameter is limited by its wavelength due to the nature of the light, and it is difficult in terms of mechanism to deflect the beam and perform desired scanning. In this respect, since the electron beam and the ion beam use electromagnetic means and the beam focusing and the beam deflection scanning are relatively easy, it can be said that the electron beam and the ion beam are suitable for manufacturing this kind of ultra-fine three-dimensional structure. However, when a focused electron beam is used, the mass and particle size of the electrons are small, so that the irradiated electron penetrates the sample beyond the sample target to be deposited and deposits in an unintended place. With this phenomenon, there is a problem that a desired place cannot be formed successfully. In summary, it can be said that a method using a focused ion beam is most suitable for manufacturing an ultrafine three-dimensional structure. Therefore, there are currently various attempts by researchers to use this focused ion beam.
[0003]
Deposition using this focused ion beam apparatus will be described with reference to FIG. Reference numeral 1 denotes an ion source, from which ions are extracted by a voltage applied to an extraction electrode, are focused into a beam shape by the ion optical system 3, are subjected to a deflecting action by a deflector, and are irradiated onto a desired portion of the sample surface. A source gas is blown from the gas gun 6 toward the vicinity of the surface of the sample 7 to be deposited placed on the sample stage 4. Then, an adsorbed layer of the sprayed source gas is formed on the surface of the region of the sample 7, and when the focused ion beam 2 is irradiated there, ions react with the source gas, and a certain product is volatilized. Is deposited on the sample surface. When the focused ion beam 2 is scanned over a predetermined area of the sample 7 by the deflector, the deposit forms a thin film in that area. The deposition using this focused ion beam apparatus is performed by forming a protective film to protect peripheral damage when processing semiconductor devices by sputter etching or gas assist etching using a focused ion beam, It has just been used to repair white defects (missing defects) such as masks.
[0004]
The inventor's group has developed a technique for laterally growing a material in the course of research for bridging groove defects in the field of repairing white defects such as semiconductor devices and photomasks. This technology has been filed for patent as Japanese Patent Application No. 2000-333368 “Method for forming a beam-like film pattern”. In this technique, deposition is performed in the strip-shaped irradiation region from the groove end portion to the groove-shaped defect of the element, and the deposition layer is grown in the center direction while gradually moving the irradiation region to the center of the opening. . As a phenomenon at this time, an inclined surface is formed on the tip side of the deposition layer D as shown in FIG. The inclined surface is formed because, at the beginning of irradiation, the tip side of the irradiation region has no foundation to be attached, so that the attachment proceeds sequentially from the end. However, once the foundation is formed, the deposition layer D is formed thereon, and when the irradiation time for the same region is made longer, the deposition layer D is simply thicker as indicated by the alternate long and short dash line b in FIG. In addition, the inclined surface disappears and becomes a flat deposition surface. If the irradiation region is shifted and the deposition layer is formed after the edge on the growth tip side of the deposition layer D stands up like that, the next strip deposition layer is moved upward and distally as shown in FIG. We have found that a step-like film grows. In the previous application invention, when the tip side of the deposition layer D is formed like a ridge, the next deposition is executed by shifting the irradiation region to the tip side so as to overlap the inclined surface portion. The deposition layer D at the second time is also formed with an inclined surface as indicated by a broken line a in FIG. When this state is reached, the irradiation region is further shifted to the tip side, and the deposition layer D is successively grown to the tip side. In the film formation by this method, as shown in FIG. 3B, each strip deposition layer does not have a step shape, and a long cantilever with a constant bottom surface can be formed. It has been confirmed that the film can be grown right beside and has a thickness of more than 10 times the thickness of the thin film, and the thickness can be uniform and flat.
[0005]
As described above, the inventors of the present invention based on the fact that deposition growth in the ion source direction and deposition in the ion beam vertical direction are possible by the CVD method that irradiates the focused ion beam. No. 363573 “Creation of ultra-fine three-dimensional structure and apparatus” was filed The present invention is a deposition technique using a focused ion beam apparatus, using phenanthrene as a source gas and ions of 5 to 100 keV gallium or gold, silicon, beryllium or the like from a liquid metal ion source as ions. In this method, the spraying density is increased by about 5 to 10 times as compared with the conventional deposition, and the gas spraying direction is made equal or symmetrical. This method made it possible to form a three-dimensional shape such as a drill or a coil. However, the deposition of a focused ion beam based on this CVD method does not promote the growth from the vertical direction to the downstream side of the ion beam. Therefore, it was impossible to form a shape that warped downward.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a technique capable of forming a three-dimensional ultra-fine three-dimensional structure that is warped downward by a CVD method in which a focused ion beam is irradiated while blowing a source gas on a sample surface. It is in.
[0007]
[Means for Solving the Problems]
The present invention uses phenanthrene as a source gas, ions of 5 to 100 keV gallium or gold, silicon, beryllium, etc. from a liquid metal ion source as ions, and the gas blowing density is higher than in the case of conventional deposition, A deposition technique using a focused ion beam apparatus that blows gas. First, a step of forming a base portion, a step of tilting a sample stage when a base protrusion is formed, A method of irradiating the beam and moving the irradiation area toward the upper side of the stage inclined surface was adopted.
Also, as the stage driving mechanism, a xyz-axis three-dimensional moving and rotating and tilting five-axis driving system is used, and the rotational axis is provided on the tilting mechanism so that the positional relationship between the structure and the ion beam is free. Increased the degree.
Furthermore, by combining these new methods and mechanisms with deflection scanning and stage drive control, a free three-dimensional structure can be formed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention uses phenanthrene as a source gas, ions of 5 to 100 keV gallium or gold, silicon, beryllium, etc. from a liquid metal ion source as ions, and the gas blowing density is higher than in the case of conventional deposition, In a deposition technique using a focused ion beam apparatus that blows a gas, a step of forming a base portion, a step of tilting a sample stage when a base protrusion is formed, and irradiating the base portion with a beam At the same time, the above-described growth method in the horizontal direction in which the irradiation area is moved sequentially above the stage inclined surface is applied and applied. In the present invention, it is impossible to grow the deposition structure below the horizontal direction with respect to the incident beam from above, but in view of the fact that it can be grown in the horizontal direction by the previous technique. This is based on the knowledge that the structure can be grown from the projecting portion within an angle range of ± θ by inclining the portion by θ angle and performing growth in the horizontal direction from that portion. That is, it becomes possible to grow the deposition structure obliquely downward at a maximum of the θ angle. As shown in FIG. 1A, a columnar protrusion B serving as a base is formed on the surface of the sample 7 by normal deposition in which the ion beam 2 is irradiated while blowing the source gas from the gas gun 6. This is due to conventional deposition performed without moving the illumination area. Subsequently, as shown in FIG. 5B, the stage 4 is tilted, the tip of the columnar protrusion B tilted in the oblique direction is irradiated with the ion beam 2, and the irradiation region is sequentially moved by the inventor previously presented. If horizontal deposition is performed, the structure can be grown at a horizontal angle orthogonal to the beam. When the irradiation area moving direction at this time is the maximum tilt angle direction of the stage inclined surface, a structure can be formed that grows at an angle θ downward from the tip of the columnar protrusion B as shown in FIG.
[0009]
The relationship between the tilt angle of the stage and the structure growth direction based on the moving direction of the irradiation region is confirmed with reference to FIG. In FIG. 5A, the incident direction of the ion beam is taken as the y-axis, the orthogonal direction is taken as the x-axis, and this is taken as the horizontal direction for convenience of understanding. Now, the sample stage is set at an angle of θ with respect to the x-axis, and an ion beam irradiation region is set at the apex P of the base portion B formed in a columnar shape from the origin position O. When the ion beam irradiation area is moved in the horizontal direction (the maximum tilt angle direction of the stage) and the horizontal deposition is performed, the structure grows from the point P to the left in the horizontal direction. On the other hand, when the horizontal deposition is performed by moving the irradiation area in the right direction of the drawing (the direction of the maximum tilt angle of the stage), the structure grows from the point P to the right in the horizontal direction. When this stage is returned to the x axis, that is, in the horizontal direction, the structure when the horizontal deposition is performed by moving the stage in the maximum tilt angle direction of the stage as shown in FIG. On the other hand, the structure grows obliquely downward at the θ angle, and the structure when the horizontal deposition is performed by moving in the direction of the maximum downward angle of the tilt angle of the stage grows obliquely upward at the θ angle with respect to the base apex P is doing. When the irradiation area is moved at another angle with respect to the stage, the growth is in the direction of angle φ in the range of + θ>φ> −θ. Incidentally, when the irradiation area is moved in the direction perpendicular to the plane of the paper (horizontal movement direction with respect to the stage) in A in the figure, the structure grows right side (horizontal direction) from the point P, and a right-angle structure is formed. become.
[0010]
Next, a method for forming the structure in a curved shape instead of a linear shape will be described. If the area is moved in one direction starting from point P with the stage fixed, a linear structure is formed. By moving the irradiation area while changing the tilt angle of the stage as shown in FIG. A structure that bends up and down can be formed. As shown in FIG. 3A, the stage is inclined by the θ angle, and a beam irradiation region is set at the base portion apex P of the columnar protrusion shape. If the stage tilt angle is moved slowly in the range of θ + α>φ> θ−α while moving the stage tilt angle in the maximum climb angle direction and horizontal deposition is performed, the horizontal direction will change according to the change in tilt angle. As shown in (b) of the figure, if the φ angle is decreased, the growth direction is directed upward, then it is increased in the direction of increase. Turn to. When the structure thus formed is observed by returning the stage to a horizontal position, the structure extends in a undulating manner downward as shown in FIG.
[0011]
The above is the formation of the linear structure. Here, the formation of the planar structure facing downward will be described. As shown in FIG. 4A, an ion beam irradiation region is set at the apex P of the projecting base B, and the beam is moved stepwise while swinging the beam in the orthogonal direction. As shown in the figure, when the width to be swung in the orthogonal direction is gradually increased, a fan surface that becomes wider toward the front is formed as shown in FIG. The formed surface in this case extends obliquely downward as shown in FIG. Of course, the width is not limited to the end, but if the swinging width is constant, it will be a strip of the same width. It can respond to anything like that.
[0012]
Furthermore, in the present invention, the structure is grown downward from the start point by moving the irradiation region of the ion beam from the start point of the structure in the upward direction of the stage surface with the stage tilted. The ion beam focusing device functional for forming a three-dimensional structure is provided by combining the stage drive with the method based on the method. The stage driving mechanism according to the present invention is a five-axis driving mechanism that moves, rotates, and tilts at least in the three-dimensional direction of the xyz axis. By adopting such a configuration, the degree of freedom in the positional relationship between the structure and the ion beam could be increased. A conventional 5-axis drive has a rotation mechanism around the z-axis. According to this mechanism, the irradiation area can be moved by rotational driving to form a loop shape only when the loop surface is horizontal. For example, in order to form a tubular body having an inclined direction, it is necessary to control the movement of the irradiation area having a loop shape by deflecting scanning after the stage is inclined. If the tubular body is simply oriented in one direction, the control is extremely difficult if the tubular body is complicatedly bent. However, with the drive mechanism of the present invention in which the rotation mechanism is placed on the inclined surface, a simple tubular body facing one direction can be easily formed by rotating the stage and then rotating it, Even if the tubular body is bent in a complicated manner, if the inclination is controlled so that the loop surface at that time becomes horizontal, a tubular body that is bent in a complicated manner can be formed by a simple rotational drive.
The present invention makes it possible to form a variety of three-dimensional structures by the above-described new method enabling the downward growth of the structure and the new mechanism in which the stage rotational drive mechanism is mounted on the tilt stage. However, the various three-dimensional structures can be easily formed by combining the deflection scanning control of the ion beam and the drive control of the stage.
[0013]
【The invention's effect】
The method of growing the micro three-dimensional structure obliquely downward according to the present invention is a deposition technique using a focused ion beam device, and forms a base portion by increasing the gas spray density compared to the conventional deposition. And a step of tilting the sample stage when the base protrusion is formed, and a step of sequentially irradiating the base with a beam and moving the irradiation region sequentially above the stage inclined surface. Therefore, it is possible to form a structure extending downward, which was not considered by conventional common sense. For example, it is possible to form a deposit of a structure with a tip bent downward, such as a lily petal or a daffodil leaf.
In the method for three-dimensional growth of a fine three-dimensional structure according to the present invention, the step of irradiating the base portion with the beam and sequentially moving the irradiation area and slowly changing the tilt angle of the stage is performed. Thus, the formation including the lower part of the extending structure was made possible.
Furthermore, the three-dimensional growth method of the micro three-dimensional structure of the present invention is a planar structure extending from the base portion by moving the beam in a stepwise manner in the direction of climbing the stage inclination angle while swinging the beam in a direction orthogonal to the base portion. The formation including the lower part of the body was made possible.
[0014]
The focused ion beam apparatus of the present invention is a device having a drive mechanism of five axes (x, y, z directions and rotation, tilt) or more, and further has a further rotation mechanism at the top so as to be orthogonal to the sample stage. Since it was provided, various formations including downward growth of 3D structures by deposition were made easy.
In addition, the three-dimensional growth method of the micro three-dimensional structure according to the present invention includes the six axes (x, y, z directions and rotation × 2, tilt) provided at the top so that the rotation axis of the rotation mechanism is orthogonal to the sample stage. ) Deposition technology that uses the focused ion beam device with the above drive mechanism to move the ion beam irradiation area sequentially and grow it horizontally, deflection scanning control, and driving of the stage such as tilt and rotation Since it can be combined with control as appropriate, various three-dimensional structures including downward growth can be formed.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the principle of realizing downward growth of an ultrafine three-dimensional structure by the method of the present invention.
FIG. 2 is a diagram for explaining a relationship between a tilt angle of a stage and a structure growth direction based on a moving direction of a beam irradiation region.
FIG. 3 is a diagram for explaining the principle of realizing the growth of an ultrafine three-dimensional structure that bends up and down by the method of the present invention.
FIG. 4 is a diagram illustrating the principle of realizing planar growth of an ultrafine three-dimensional structure by the method of the present invention.
FIG. 5 is a diagram illustrating a general configuration of a focused ion beam apparatus.
FIG. 6 is a diagram for explaining a phenomenon of deposition using a focused ion beam as a basis of the present invention.
[Explanation of symbols]
2 Ion beam B Base 4 Sample stage O Origin 6 Gas gun P Vertex 7 Sample

Claims (6)

Deposition technology using a focused ion beam device,
Spraying a deposition source gas, irradiating a beam, and forming a base part;
Tilting the sample stage on which the foundation portion is placed ;
The growth method of a fine three-dimensional structure by CVD and a step of sequentially moving the irradiation area upwardly of the inclined surface of the sample stage irradiates the basis portion of the beam. Deposition technology using a focused ion beam device,
Spraying a deposition source gas, irradiating a beam, and forming a base part;
Tilting the sample stage on which the foundation portion is placed ;
Sequentially and step of varying the tilt angle of the sample stage is moved, growth method of a fine three-dimensional structure by CVD with an irradiation region irradiates the beam to the base portion. Deposition technology using a focused ion beam device,
Spraying a deposition source gas, irradiating a beam, and forming a base part;
Tilting the sample stage on which the foundation portion is placed ;
Growth method of the, and moving stepwise the inclination angle climbing direction of the sample stage shaking in a direction perpendicular to the beam to the base portion by CVD with a fine three-dimensional structure. In a focused ion beam apparatus having a drive mechanism of 5 axes (x, y, z directions and rotation, tilt) or more,
A focused ion beam device characterized by facilitating formation including a downward growth of a three-dimensional structure by deposition by providing a further rotation mechanism at the uppermost position so as to be orthogonal to the sample stage. Using a focused ion beam apparatus equipped with a driving mechanism of six or more axes (x, y, z directions and rotation and tilt) provided at the top so that the rotation axis of the rotation mechanism is orthogonal to the sample stage, an ion beam is used. A variety of three-dimensional structures including downward growth by appropriately combining deposition technology that sequentially moves the irradiation area of the substrate and growing it in the horizontal direction, control of deflection scanning, and drive control of the sample stage such as tilt and rotation growth method of a fine three-dimensional structure by CVD to allow formation of the body. In a focused ion beam apparatus having a 5-axis stage drive mechanism for controlling a focused ion beam incident angle on a sample placed on a sample stage and a scanning control mechanism for performing scanning irradiation of the focused ion beam,
  The stage drive mechanism includes a three-axis drive mechanism in the x, y, and z directions, a rotation drive mechanism, and a tilt drive mechanism.
  The rotational drive mechanism is a focused ion beam device installed on the tilt drive mechanism.

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