JP2001168070A - Gas supply mechanism for focus ion beam system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism for supplying gas from a nozzle to a deep machining part of a sample in which the interval between the nozzle and the sample can be adjusted readily with high accuracy without having any effect on the surface state of the sample. SOLUTION: A sample stage 5 and a gas supply unit 9 are disposed in the sample chamber 7 of a focus ion beam system and a microscope 31 is interposed between a sample 6 on the sample stage 5 and the gas nozzle 10 of the gas supply unit 9. A control computer 46, a control monitor 47 and a controller 48 are disposed on the outside of the sample chamber 7. Interval between the sample 6 and the gas nozzle 10 is adjusted by means of an interval adjusting mechanism and the angle of the gas nozzle 10 is adjusted by means of a nozzle angle varying mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply mechanism for a focused ion beam apparatus, and more particularly, to a gas gun having a tip portion set at an arbitrary angle to an LSI (large-scale integrated circuit) or the like from various directions. The present invention relates to a gas supply mechanism capable of supplying a gas to a sample.

[0002]

2. Description of the Related Art Conventionally, a focused ion beam (hereinafter referred to as FI
The device (referred to as B) is used not only in semiconductors but also in various fields. Taking a semiconductor as an example, an FIB apparatus is used to locally irradiate an ion beam to a wiring connecting between circuits of an LSI and cut off the wiring by causing a sputtering phenomenon on molecules in the wiring. In addition, the FIB apparatus uses FIB excitation CVD (chemical vapor deposition),
An arbitrary region of a semiconductor can be formed into a film or a metal wiring can be formed to connect circuits. Further, the FIB apparatus can perform gas-assisted etching using various gases.

Before describing a conventional FIB apparatus, the F
The principle of IB excitation CVD and gas assisted etching will be briefly described. Regarding FIB excitation CVD, FIG.
As shown in (a), the surface of the sample 106 in the sample chamber is
(Tungsten) 120 and CO (carbon monoxide) 121, a compound gas of tungsten hexacarbonyl W (C
O) ₆ gas 119 is injected to adsorb W (CO) ₆ gas 119 on the surface of the sample. Next, as shown in FIG.
The FIB 104 is irradiated only to a region where a wiring is to be formed. W (CO) _{6 in} the irradiated area is sputtered by the FIB 104 and separated into W 120 and CO 121. Further, the separated CO121 is discharged out of the sample chamber by the vacuum pump, while W120 remains in the FIB irradiation area and is laminated with the passage of time. For example, a metal wiring is formed by the laminated W120.

Next, regarding gas assisted etching,
This will be described with reference to FIGS. Xenon fluoride gas and chlorine gas are typical examples of the assist gas used in the semiconductor field. Xenon fluoride gas is used in LSI
Is used to etch an insulating film used in the manufacturing process of the above, and chlorine gas is used to etch a metallic film. When the sample is etched using the FIB apparatus, as shown in FIG. 11A, the atoms of the sample are ejected by sputtering to form an etching hole 123, and the atoms of the etching hole 123 are ejected to progress the etching. I do. The ejected atoms 122 are discharged out of the apparatus by a vacuum pump. However, FIG.
As shown in (a), when etching is performed without using an assist gas, the ejected atoms are reattached to the side wall portion of the etching hole 123 as the etching depth increases, and the etching does not proceed. On the other hand, FIG.
As shown in (b), when the etching is performed by injecting the assist gas 124 onto the surface of the sample, the atoms 122 ejected by sputtering are blown off, making it difficult to reattach (redeposition) the etching holes 123. Therefore, when the assist gas is used, reattachment of atoms is reduced, so that more atoms 122 are ejected from the etching holes 123 as compared with the case where the assist gas is not used,
A deep etching hole can be formed in a short time.

FIG. 12 shows a conventional FIB device. Using this FIB apparatus, FIB excitation CVD or gas assisted etching is performed. In order to perform FIB excitation CVD or gas assisted etching, as shown in FIG. 12, an ion beam is extracted from an ion source 101 by a high electric field and passes through an electrostatic lens (not shown) contained in a lens barrel 102. It is focused to a minimum diameter of 0.01 μm. In order to stably focus the ion beam, a vacuum pump 103 is provided on the side of the lens barrel 102, and the inside of the lens barrel 102 is always kept at a high vacuum.
The FIB 104 irradiates a sample 106 fixed on a sample stage 105 installed in a sample chamber 107,
The secondary electrons or secondary ions emitted from the surface of the detector 06 are detected by the detector 108, and the detected secondary electrons or secondary ions can be visually observed as a surface image after image processing. The sample chamber 107 is pulled by the vacuum pump 103 similarly to the lens barrel 102, and a high vacuum state is maintained. A gas supply unit 109 is installed on the side of the sample chamber 107, and the gas supplied to the gas supply unit 109 is
The gas is sprayed from the gas nozzle 110 onto the surface of the sample 106.
The gas of the gas supply unit 109 is supplied from a gas cylinder 111 via a pipe 112. Between the pipe 112 and the sample chamber, a flow controller 113 for adjusting the flow of gas is provided, which serves to control that the degree of vacuum in the sample chamber is excessively reduced by ejecting gas to the sample surface. have.

FIG. 13 is an enlarged view of the conventional gas supply unit of FIG. When performing the above-described FIB excitation CVD or gas assisted etching, the gas supply unit 109
Is moved toward the center of the sample chamber 107. The gas supply unit 109 is moved by three moving stages attached to the gas supply unit 109, that is, an X-axis stage 114, a Y-axis stage 115, and a Z-axis stage 116. The above gas supply unit 1
After moving 09, the gas nozzle 110 is made to approach the surface of the sample up to the set interval 117. At this time, the gas nozzle 110 is arranged at a predetermined angle 118 fixed to the sample surface. The sample 106 is the sample stage 1
The FIB 10 is fixed on the sample 105 from above.
4 are irradiated. The sample stage 105 is a five-axis movable stage that can move in the X-axis direction, the Y-axis direction, the Z-axis direction, the tilt direction (T direction), and the rotation direction (R direction).

The above-mentioned gas nozzles include those made of a single nozzle and those made of a plurality of nozzles having different angles from each other, and these are selectively used depending on the type of FIB excitation CVD or gas assisted etching to be used. .

Generally, there are two types of conventional gas supply units, a fixed type and a movable type, as shown in FIGS. 14 (a), (b-1) and (b-2). The movable gas supply unit includes a type that can be moved by a compressed gas shown in FIG. 14B-1 and a type that can be moved by a motor shown in FIG. 14B-2. The fixed gas supply unit of FIG. 14A has a structure in which the gas supply unit 109 is fixed to the sample chamber 107 and the gas nozzle 110 cannot be moved to an arbitrary position. When adjusting the interval 117 between the sample 106 and the gas nozzle 110, the sample stage 1
05 is adjusted in the Z-axis direction. FIG.
The movable gas supply unit shown in FIG. 4 (b-1) has a structure in which the gas supply unit can be moved only in a certain direction by using a compressed gas. When FIB excitation CVD or gas-assisted etching is used, the movable gas supply unit is moved to a place where FIB-excited CVD or gas-assisted etching is performed, and then the nozzle 110 is used out. When FIB excitation CVD or gas-assisted etching is not used, the movable gas supply unit is placed at a position away from the sample 106. This is because when the sample stage 105 is moved while the sample surface and the gas nozzle 110 are always close to each other, the height of the sample 106 changes due to unevenness on the sample surface, so that the sample 106 and the nozzle 110 do not come into contact with each other. It is. FIG.
The movable gas supply unit shown in FIG.
The gas adjusting unit 109 can be moved in the X-axis, Y-axis, and Z-axis directions by a motor. By moving the gas supply unit 109 itself, the gas supply unit 109 can be arranged at an arbitrary position with respect to the sample 6, and the height of the gas nozzle 110 can be adjusted. 14 (a), (b-1) and (b-2) are all developed for the purpose of facilitating the positioning of the gas nozzle 110 with respect to the sample 106. It is premised that FIB-excited CVD or gas-assisted etching is performed under predetermined limited conditions.

When FIB excitation CVD or gas assisted etching is performed in the FIB apparatus, the gas pressure on the sample surface is an important condition for controlling the processing speed and the processed shape. In particular, a high gas pressure is required in a region where the current density of the FIB is high, that is, in a processing region. Generally, FIB-excited CVD and gas-assisted etching cannot be realized without a gas pressure of about 1 Torr at a current density of 10 A / cm ² . Further, when the irradiation speed of the FIB cannot be increased, it is necessary to increase the gas pressure. However, if the degree of vacuum in the sample chamber is excessively reduced by increasing the gas pressure, the convergence state of the FIB is adversely affected, and the processed shape is deteriorated.

FIG. 15 is a graph showing the relationship between the gas pressure injected from the nozzle and the distance between the gas nozzle and the sample surface. As shown in the graph of FIG. 15, since the gas pressure is significantly reduced when the gas nozzle is separated from the sample surface, it is necessary to bring the nozzle as close as possible to the sample surface in order to obtain a high gas pressure. Therefore, it is very important to accurately control the distance between the sample stage and the gas nozzle.

A plurality of methods for controlling the distance between the sample stage and the gas nozzle are described in JP-A-8-7823. In the first method, the control device is composed of a probe that is telescopically attached to the tip of the nozzle, and a current detection circuit that is electrically connected to the probe, and the probe contacts the sample surface. When the length is reduced, a predetermined current flows through the current detection circuit, and it is recognized that the probe has come into contact with the sample. In the second method, a laser device and a light receiving device are provided between the sample surface and the gas nozzle, and a detection device that outputs a light receiving state of the laser light as a change in an electric signal is provided. If the sample is accidentally brought too close to the gas nozzle, the detection device recognizes that the gas nozzle is approaching the sample because the surface of the sample blocks the laser beam. In the third method, a plate electrode is provided at the tip of the gas nozzle, and a current detection circuit is further provided, and the capacitance between the plate electrode and the sample is detected by the current detection circuit. This current detection circuit detects a changing capacitance when the gas nozzle comes too close to the sample surface, thereby preventing the gas nozzle from contacting the sample.

[0012]

However, in the first conventional method for controlling the distance between the sample stage and the gas nozzle, it is necessary to bring the probe into relatively strong contact with the sample.
In some cases, there is a risk of damaging the sample surface. Further, in the second method, since the outer frame, that is, the mold portion blocks the laser beam before the sample blocks the laser beam, the distance between the nozzle and the surface of the sample embedded in the mold is adjusted. However, there is a drawback that only a flat sample having no outer frame can be used. Furthermore, in the third method, since the capacitance varies depending on the shape of the sample surface in this method, the intervals have not been accurately adjusted.

That is, as a first problem to be solved by the present invention, for example, a semiconductor wafer or package
When performing IB excitation CVD or gas assisted etching, if the wafer is warped, the package is inclined and fixed, or the surface is significantly uneven, the distance between the gas nozzle and the sample does not fall within a predetermined range. In addition, there is a problem that a desired processing shape cannot be obtained due to a change in gas pressure at the processing location.

As a second problem to be solved by the present invention, as described above, the gas pressure on the sample surface is a factor for controlling the processing speed and the processing shape. In particular, if the gas pressure is not sufficient, Holes with a high aspect ratio cannot be formed using gas assisted etching. However, if the gas pressure is simply increased, the amount of gas increases, the degree of vacuum in the sample chamber is reduced, and the focusing state of the FIB is deteriorated, resulting in a problem that the processed shape is deteriorated.

Further, as a third problem to be solved by the present invention, when a buried contact of a W wiring is formed by FIB excitation CVD in a hole etched with a high aspect ratio, FIG.
As shown in FIG. 6, the pressure of the gas 125 from the nozzle 110 is insufficient, so that the gas 125 does not easily enter the inside of the etching hole 123, and a state occurs in which the vapor is deposited while being etched. Therefore, there is often a problem that a cavity 126 is formed inside the etching hole 123 and a high resistance is obtained even when a contact is made.

Accordingly, an object of the present invention is to provide a gas supply mechanism that can easily and accurately adjust the distance between a nozzle and a sample without being affected by the surface condition of the sample, and that supplies gas from the nozzle to a deep portion of the sample. Is to provide.

[0017]

In order to achieve the above object, a gas supply mechanism of a focused ion beam apparatus according to the present invention moves in an X-axis direction, a Y-axis direction, a Z-axis direction, a tilt direction, and a rotation direction. Move to an arbitrary position in a gas supply mechanism of a focused ion beam apparatus that irradiates a focused charged particle ion beam onto a surface of a sample placed on a possible five-axis movable stage to etch the surface of the sample. It is characterized by being provided with a gas nozzle which can be changed at any angle.

According to the above configuration, since the gas supply mechanism is provided with the gas nozzle which can be moved to an arbitrary position and at an arbitrary angle, the distance between the nozzle and the sample is adjusted easily and with high precision. Processing fluctuations due to alignment errors are prevented, and the nozzle tilt angle is freely adjusted so that the deposition gas from the nozzle is supplied deep into the sample, ensuring high aspect ratio processing and metal embedding. Done in

The gas supply mechanism of the focused ion beam apparatus according to one embodiment of the present invention has a microscope for monitoring the angle of the gas nozzle in real time and a control computer for adjusting the angle of the gas nozzle to an arbitrary angle. It is characterized by having means.

According to the above configuration, the gas supply mechanism of the focused ion beam device has an angle adjustment having a microscope for monitoring the angle of the gas nozzle in real time and a control computer for adjusting the angle of the gas nozzle to an arbitrary angle. Since the means is provided, the angle of the gas nozzle is adjusted to an arbitrary angle with high accuracy by the microscope and the control computer.

The gas supply mechanism of the focused ion beam apparatus according to the present invention comprises a sample supply mechanism mounted on a five-axis movable stage movable in the X-axis, Y-axis, Z-axis, tilt and rotation directions. In a gas supply mechanism of a focused ion beam apparatus that irradiates a focused charged particle ion beam onto a surface to etch the surface of the sample, a minute current flowing between the surface of the sample and the tip of the gas nozzle is detected. It is characterized by having a current detection device.

According to the above configuration, the gas supply mechanism is provided with the current detecting device for detecting a minute current flowing between the surface of the sample and the tip of the gas nozzle, so that the surface of the sample contacts the tip of the gas nozzle. Is detected.

In one embodiment of the invention, the gas supply mechanism of the focused ion beam apparatus performs etching while supplying an etching promoting gas from a high inclination angle to an arbitrary region on the surface of the sample, thereby obtaining a high aspect ratio. It is characterized in that it is possible to carry out the processing.

According to the above configuration, the etching is performed on an arbitrary region on the surface of the sample while supplying the etching promoting gas from a high inclination angle. Therefore, the etching promoting gas can be supplied without increasing the amount of the etching promoting gas. The gas pressure is increased, and the etching of the sample reaches a deep portion of the sample, thereby enabling processing with a high aspect ratio.

In one embodiment of the invention, the gas supply mechanism of the focused ion beam apparatus processes a hole having a high aspect ratio by etching the surface of the sample while supplying an etching promoting gas from a high inclination angle. rear,
By using FIB excitation CVD to deposit the metal in the deposition gas into the hole while supplying the deposition gas from the high angle into the hole, it is possible to ensure that the metal is embedded in the hole. It is made possible.

According to the above configuration, the metal in the vapor deposition gas is vapor-deposited into the hole while supplying the vapor deposition gas into the hole at a high inclination angle using FIB excitation CVD. The vapor pressure of the vapor deposition gas is increased without increasing the vapor deposition gas, and the vapor deposition gas reaches the deep part of the hole of the sample, and the vapor deposition metal is reliably embedded in the hole.

The gas supply mechanism of the focused ion beam apparatus according to the present invention includes a gas supply unit, a pipe detachably attached to the gas supply unit, a tip end of the pipe and a rotary mounted on the gas supply unit. And a pipe angle adjusting device connected to the mechanism.

According to the above configuration, the gas supply unit,
Since the pipe includes a pipe detachably attached to the gas supply unit and a pipe angle adjusting device connected to a tip end of the pipe and a rotation mechanism mounted on the gas supply unit, the pipe can be easily formed. The gas supply unit can be removed and replaced, and the angle of the pipe is adjusted by the pipe angle adjusting device.

The gas supply mechanism of the focused ion beam apparatus according to one embodiment of the invention is characterized in that the pipe has flexibility.

According to the above configuration, since the pipe has flexibility, the pipe is smoothly curved by the pipe angle adjusting device, and the gas in the pipe flows smoothly.

The gas supply mechanism of the focused ion beam apparatus according to one embodiment of the invention is characterized in that an elastic body is wound around the pipe.

According to the above configuration, since the elastic body is wound around the pipe and linearly supports the pipe, the pipe is supported by the elastic body in a constant linear direction unless an external force is applied to the pipe.

In one embodiment of the invention, the gas supply mechanism of the focused ion beam apparatus is characterized in that the pipe angle adjusting device is a thin plate.

According to the above configuration, since the pipe angle adjusting device is a thin plate, the thin plate does not bend in the thickness direction of the thin plate and does not bend in the direction perpendicular to the thickness direction of the thin plate.
Therefore, the pipe is curved only in the thickness direction of the thin plate, and the angle of the pipe is adjusted only in the thickness direction of the thin plate.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments.

FIG. 1 is a configuration diagram of an FIB apparatus equipped with a gas supply unit of the present invention. As shown in FIG.
In the IB apparatus, an ion source 1, that is, an ion generation source is provided at the uppermost part in a lens barrel 2 provided in a vertical direction.
The inside of the lens barrel 2 is evacuated to high vacuum by a vacuum pump 3 provided on the side of the lens barrel 2. A sample chamber 7 is provided below the lens barrel 2 so as to include the lower part. Sample room 7
Is made high vacuum by a vacuum pump 3 provided below the sample chamber 7. In the sample chamber 7, a sample stage 5 and a gas supply unit 9 are installed. Sample stage 5
A sample 6 is placed on the gas supply unit 9, and a gas nozzle 10 is attached to the gas supply unit 9. Further, a microscope 31 is provided between the sample 6 and the gas nozzle 10. The gas supply unit 9 is connected to a gas cylinder 11 provided outside the sample chamber 7. The gas in the gas cylinder 11 is supplied to the gas supply unit 9 via the gas flow controller 13 in the pipe 12. Also, the sample chamber 7
Outside the control computer 46, a control monitor 47 and a controller 48 for adjusting the position and angle of the nozzle.
Are provided.

First, in order to perform hole processing and W filling processing with a high aspect ratio, the distance between the nozzle and the sample and the angle of the nozzle are adjusted using the gas supply unit of the present invention. Adjustment of the interval between the nozzle and the sample is performed as follows.

As shown in FIG. 1, the sample 6 is fixed to the sample stage 5 in the sample chamber 7, and the inside of the sample chamber 7 is evacuated to a high vacuum of about 10 ^-7 Torr. At this time, the sample stage 5 is at the lowest position. A high electric field is applied to the ion source 1 to extract an ion beam and pass through an electrostatic lens (not shown) of the lens barrel 2 to obtain a FIB (focused ion beam) 4 having a diameter of 0.01 μm at the minimum. The lens barrel 2 and the sample chamber 7 are constantly sucked by the vacuum pump 3 and kept at a high vacuum, so that a stable FIB 4 can be obtained. The FIB 4 irradiates the surface of the sample 6, detects secondary electrons or secondary ions emitted from the sample surface by the detector 8, performs image processing, and displays the surface image on the monitor 47 of the control computer 46. .

Next, the gas nozzle 1 of the gas supply unit 9
0 is adjusted to an angle suitable for processing with a high aspect ratio.
First, the tip of the gas nozzle 10 is displayed on the control monitor 47 using the microscope 31 attached to the side of the gas supply unit 9. The operator monitors 4
7 while watching the nozzle tip 10a projected on the nozzle 7 using the dedicated controller 48 for driving.
0a is adjusted to bend downward. Although the bent gas nozzle 10 comes to have an angle with respect to the sample 6,
To adjust the angle to an arbitrary angle, the angle needs to be obtained from the gas nozzle 10 projected on the monitor 47. FIG.
(a) shows the gas nozzle 10 projected on the control monitor 47. When two points are specified on the gas nozzle 10 on the monitor 47 using a computer mouse and a line 49 is drawn, the computer calculates the angle. If the desired angle has been input to the computer in advance, the desired angle is indicated on the monitor and a line 49 is displayed.
The angle adjustment of the nozzle tip 10a is performed by setting the gas nozzle 1 on the line 49 displayed using the dedicated nozzle controller 48.
It is only necessary to set 0, and the adjustment operation is very easy. In FIG. 5A, the adjustment is performed by setting the angle of the gas nozzle tip 10a to 80 degrees.

Next, an interval adjusting mechanism for adjusting the interval between the sample surface and the gas nozzle will be described.

The gap adjusting mechanism of the present embodiment is an adjusting mechanism that can freely move, instead of reciprocating the gas supply unit in a fixed direction as in the prior art, and provides an error in sample height due to a difference in processing position. And accurately adjust the distance between the sample surface and the nozzle. That is, as shown in FIG. 2, the gas supply unit of the present invention comprises a conventional X-axis direction moving device 14 and a conventional
In addition to the axial moving device 15 and the Z-axial moving device 16, a total of six moving mechanisms including a tilt moving device 27, a rotation moving device 28, and a nozzle rotating device 29 are provided. The micromotor 30 can be operated in units of 1 μm by computer control. In addition, control software capable of registering each position is provided, and it is easy to reproduce the shape and position of the nozzle 10 after alignment. Further, in order to adjust the angle of the gas nozzle 10 described in the embodiment, a microscope 31 is provided beside the gas supply unit 9 so that the nozzle tip 1 can be up to 3,000 times.
The image of the shape of the sample 0a and the sample 6 can be observed in real time.

In order to accurately adjust the distance between the sample surface and the tip 10a of the gas nozzle, it is necessary to provide a reference adjusting mechanism. The reference in the present invention is a eucentric mechanism of the sample stage. As shown in FIG.
When the sample stage 5 is tilted while irradiating the surface of the sample 6 with the FIB 4 in a specific area without using the eucentric mechanism, the sample stage 5 is tilted about the center axis 32 of the sample stage 5, as shown in FIG. Then, the observation point 33 is shifted. In the case of the sample stage 5 using the eucentric mechanism, as shown in FIG. 3 (c), correction is made on the sample stage 5 side by the amount shifted and the observation point 33 is always located at the irradiation point of the FIB4. To be located. As a condition for using this function, as shown in FIG.
It is necessary to align the observation point 33 on the eucentric line 34 in advance. That is, as shown in FIG. 3D, the upper surface of the sample 6 is aligned with the eucentric wire 34 as shown in FIG. As shown in ()), adjustment is made so that the observation point does not escape even if the sample 6 is tilted. The error with respect to the inclination of the sample stage 5 using the eucentric mechanism is 0 to 4
It is within a range of several μm with a 5-degree inclination.

More specifically, a procedure for adjusting the distance between the tip 10a of the gas nozzle and the surface of the sample 6 using a eucentric mechanism will be described.

First, as shown in FIG. 4A, the position of the sample stage 5 is adjusted so that the upper end of the sample stage 5 and the eucentric line 34 match. Next, the gas supply unit 9 is lowered to bring the nozzle tip 10a into contact with the sample stage 5. At this time, the nozzle tip 1
The nozzle angle of 0a is previously adjusted to the nozzle angle at the time of processing. Further, the microscope 31 installed beside the sample stage 5 is moved in the X-axis, Y-axis, and Z-axis directions so that the microscope 31 can observe the sample stage surface 5 and the gas nozzle tip 10a. . A current detection circuit 36 capable of detecting a minute current is provided between the sample stage 5 and the gas supply unit 9.
As shown in (b), the nozzle tip 10a is
, The current detection circuit 36 detects the minute current 37 flowing at the time of contact, and automatically stops the gas nozzle 10 from descending. Therefore, the position of the tip 10a of the stopped gas nozzle becomes the same as the position of the eucentric 34 line. The position coordinates (Z axis) of the gas nozzle tip 10a adjusted in this way are recognized as 0 by the computer, and the gas supply unit 9 is moved upward so as not to hinder the adjustment in the next step.

Next, as shown in FIG. 4C, an adjustment is made to match the surface of the sample 6 with the eucentric line 34.
Then, the sample stage 5 is moved in the X-axis direction and the Y-axis direction to move the sample to a place 38 where high aspect ratio processing is performed. After the movement, the Z axis of the sample stage 5 is adjusted again so as to coincide with the eucentric line 34. This is performed to correct a height error because a slight inclination occurs when the sample 6 is fixed to the sample stage 5. If the eucentric wire 34 is not adjusted at the part 38 to be actually processed, the surface of the sample 6 may come into contact with the tip of the gas nozzle 10. FIG. 4C shows the case of a wafer, and FIG. 4D shows the case of a package.

Next, the sample surface 6a and the gas nozzle tip 10
After setting the interval a to an arbitrary interval (for example, 10 μm), the gas nozzle 10 is lowered. As shown in FIG.
After confirming that the gas nozzle 10 has entered the observation field of view of the monitor 47, as shown in FIG. 5 (b), the processing point 38 and the tip 10a of the gas nozzle 10 are associated on the monitor 47 of the control computer 46. , 0 coordinate point 51. Subsequent movement of the gas nozzle 10 employs a form in which the gas nozzle 10 is moved in the X and Y axis directions with reference to the coordinates of the processing location 38. For example, the tip of the gas nozzle 10 is separated from the processing portion 38 by 5 μm,
When (the direction in which the gas flows) is input to the control computer as 45 degrees, the gas supply unit 9 performs the movement in the X-axis direction, the movement in the Y-axis direction, and the rotation movement to perform the positioning as set.

When the positioning of the gas nozzle 10 is completed, the processing conditions are entered in the condition input box 50 (frame: 1 μm
□, depth: 8 μm), and input an arbitrary gas pressure at the same time. The control computer 46 calculates a gas pressure distribution map 52 for a desired nozzle angle based on the input data on the left, and displays the result on the monitor 47. The operator visually checks the displayed distribution map, and starts processing if the distribution is as desired.

As described above, regardless of the form of the wafer or the package, the sample surface 6a and the gas nozzle tip 1
It is possible to control the interval with 0a in a non-contact and highly accurate manner.

Next, a description will be given of a nozzle angle variable mechanism of a gas supply unit which enables formation of a hole having a high aspect ratio and formation of a W-buried contact.

FIG. 6 is an exploded view of the gas nozzle. The pipe 39 of the nozzle has an outer diameter of 2 mm and an inner diameter of 1 m
m, flexible vinyl chloride having a pipe length of 20 mm is used. This pipe 39 is detachably connected to the gas supply unit and can be replaced with a new pipe in case of breakage. 0.5m thick around the pipe
m stainless steel wire 40 is wound in a coil shape,
The wire 40 has elasticity. As long as no external force is applied to the pipe 39, this coil-shaped wire 40
Is always kept in a straight line. A tapered stainless steel nozzle 41 is attached to the end of the pipe 39, and the diameter of the tip of the nozzle 41 is 0.1 mm. The nozzle 41 is provided with a mounting portion 43 for a thin plate 42, and the thin plates 42 a and 42 b connected thereto are connected to a rotating arm 45 through a guide 44. The rotating arm 45 can be rotated by the micromotor 30, and the upper and lower thin plates 42a, 42b
You can push and pull. With the thin plates 42a and 42b pushed and pulled, the tip of the nozzle 41 can be directed in the vertical direction. The reason for using the thin plates 42a and 42b is that the plate is hardly deformed in a direction other than the thickness direction, so that the rotating arm 45 is provided with the upper and lower thin plates 42a and 42b.
This is to prevent the nozzle tip 41 from shifting in the lateral direction when pushing and pulling the nozzle tip 41 via.

FIG. 7A shows a cross-sectional shape of a sample processed to have a high aspect ratio when a conventional gas supply unit is used, and FIG. 7B shows a gas supply unit of the present invention. 3 shows a cross-sectional shape of a sample processed to have a high aspect ratio when the sample is processed. In the gas supply unit shown in FIG. 7A, the angle of the gas nozzle 10 is fixed to 40 degrees, and the vacuum degree of the sample chamber during the gas assisted etching is set to 4 × 10 ⁻⁶ Torr,
The beam current value used is about 50 pA. When high aspect ratio processing is performed with an opening area of 1 μm, an etching hole can be dug to a depth of 5 μm, and the aspect ratio at this time is up to 1: 5. However, in the case of an LSI having a multilayer structure, the etching holes do not reach the lower MR wiring 53 in the gas supply unit of FIG. Next, FIG. 7B shows a cross-sectional shape of a sample when the gas supply unit of the present invention is used. The angle of the gas nozzle 10 is 80
And the degree of vacuum in the sample chamber during processing is set to 4 × 10 ⁻⁶ Torr, and the beam current value used is 50 pA. When high aspect ratio processing is performed on an opening region of 1 μm, it is possible to dig an etching hole to a depth of 8 μm, and the aspect ratio at this time is up to 1: 8.
In this case, the etching hole reaches the MR wiring 53 in the lower layer, and it becomes possible to cope with a circuit change of the multilayered LSI.

That is, as shown in FIG. 8A, when the nozzle angle is small, the gas pressure Pa tends to decrease gradually even when the nozzle is moved away from the nozzle. In this case, the range L in which the effect of the gas can be obtained even in a place distant from the nozzle to some extent.
Although a is wide, gas pressure is insufficient to realize high aspect ratio processing. On the other hand, as shown in FIG. 8B, by giving the nozzle a large angle, the range Lb in which the effect of the gas can be obtained is narrowed, but the pressure Pb of the gas tends to be high. In the case of high aspect ratio processing, since a wide range of processing area is not required, it is desirable to obtain a high gas pressure. Therefore, it can be said that a small nozzle angle is not suitable for high aspect ratio processing.

An embodiment in which the nozzle angle is changed and FIB excitation CVD is performed in the same manner as in the gas assisted etching will be described. FIGS. 9A and 9B show cross-sectional shapes when a FIB excitation CVD process is performed on a small deep hole (aspect ratio 1: 8) opened by gas assisted etching. In the conventional method shown in FIG. 9A, the angle of the gas nozzle is fixed at 40 degrees, the degree of vacuum in the sample chamber during processing is 6 × 10 ⁻⁶ Torr, and the beam current value used is 50 pA.
And A hole with an opening area of 1 μm and a depth of 8 μm,
When the W film is buried in an area of 60% of the opening area,
The W film is formed on the bottom, the side wall, and the top of the etching hole, and the center is hollowed. This is because the supply gas W (CO) ₆ reaching the bottom surface of the etching hole becomes insufficient, and reacts at the side wall portion 55 until the gas reaches the bottom surface 54 of the etching hole, and the deposition of W proceeds from the side wall direction. Because. That is, W accumulates on the side wall and the etching hole is covered, and the inside becomes hollow.

In the gas supply unit of the present invention, the angle of the gas nozzle is increased to 80 degrees, and the distance between the sample and the nozzle is set to 0.0.
When excitation CVD is performed by approaching 5 μm, FIG.
As shown in (b), the inside 56 of the etching hole can be completely buried.

[0055]

As is apparent from the above description, according to the gas supply mechanism of the focused ion beam apparatus of the present invention, X
A focused charged particle ion beam is irradiated on the surface of a sample placed on a five-axis movable stage that can move in the axial direction, the Y-axis direction, the Z-axis direction, the tilt direction, and the rotation direction. In the gas supply mechanism of the focused ion beam device that etches the surface, a gas nozzle that can be moved to any position and can be at any angle is provided, so the distance between the nozzle and the sample is adjusted easily and with high precision. In addition to preventing processing fluctuations due to alignment errors, the nozzle inclination angle can be adjusted freely, so that the deposition gas from the nozzle is supplied to the deep part of the sample, ensuring high aspect ratio processing and metal embedding processing. It can be carried out.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, the angle having the microscope for monitoring the angle of the gas nozzle in real time and the control computer for adjusting the angle of the gas nozzle to an arbitrary angle. Since the adjusting means is provided, the angle of the gas nozzle can be adjusted to an arbitrary angle with high accuracy by the microscope and the control computer.

According to the gas supply mechanism of the focused ion beam apparatus of the present invention, the gas supply mechanism is mounted on the five-axis movable stage that can move in the X-axis direction, the Y-axis direction, the Z-axis direction, the tilt direction, and the rotation direction. In a gas supply mechanism of a focused ion beam apparatus that irradiates a focused charged particle ion beam onto a surface of a sample and etches the surface of the sample, a small current flowing between the surface of the sample and the tip of the gas nozzle is applied. Since the current detection device for detection is provided, it is possible to detect that the surface of the sample comes into contact with the tip of the gas nozzle.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, an arbitrary region on the surface of the sample is etched while supplying the etching promoting gas from a high inclination angle. By increasing the gas pressure of the etching promoting gas without increasing the amount of the etching, the etching of the sample reaches the deep portion of the sample, and processing with a high aspect ratio can be performed.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, a hole having a high aspect ratio is processed by etching the surface of the sample while supplying an etching promoting gas from a high inclination angle. After that, using FIB excitation CVD, the metal in the vapor deposition gas is vapor-deposited in the hole while supplying the vapor deposition gas into the hole from a high inclination angle, so that the vapor deposition is performed without increasing the amount of the vapor deposition gas. By increasing the gas pressure of the gas, the deposition gas reaches the deep part of the hole of the sample, and the deposition metal can be reliably embedded in the hole.

According to the gas supply mechanism of the focused ion beam device of the present invention, the gas supply unit, the pipe detachably attached to the gas supply unit, the tip of the pipe and the gas supply unit are mounted. And a pipe angle adjusting device connected to the rotating mechanism, so that the pipe can be easily removed and replaced by the gas supply unit, and the angle of the pipe can be adjusted by the pipe angle adjusting device.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, since the pipe has flexibility, the pipe is smoothly curved by the pipe angle adjusting device to smooth the gas in the pipe. Can be flushed.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, since the elastic body is wound around the pipe and supports the pipe in a straight line, the pipe is not affected unless an external force is applied to the pipe. It is supported in a certain linear direction by the elastic body.

According to the gas supply mechanism of the focused ion beam apparatus of one embodiment of the present invention, since the pipe angle adjusting device is a thin plate, the thin plate bends in the thickness direction of the thin plate and extends in the direction perpendicular to the thickness direction of the thin plate. Does not bend, so that the pipe bends only in the thickness direction of the thin plate, and the angle of the pipe is adjusted only in the thickness direction of the thin plate.

[Brief description of the drawings]

FIG. 1 is a FIB equipped with a gas supply unit of the present invention.
It is a block diagram of an apparatus.

FIG. 2 is an enlarged view of the gas supply unit of FIG.

FIG. 3 is a diagram illustrating the principle of a eucentric mechanism.

FIG. 4 is a diagram showing a process of adjusting a distance between the gas supply unit of FIG. 1 and a sample surface.

FIG. 5 shows a gas nozzle image when adjusting the position and the tilt angle.

FIG. 6 is an exploded view of a gas nozzle.

FIG. 7 is a shape comparison diagram of high aspect ratio processing.

FIG. 8 is a distribution diagram of gas pressure when the inclination angle of the gas nozzle is changed.

FIG. 9 is a shape comparison diagram of W embedding processing.

FIG. 10 is a principle diagram of FIB excitation CVD.

FIG. 11 is a principle diagram of gas assisted etching.

FIG. 12: FIB equipped with a conventional gas supply unit
It is a block diagram of an apparatus.

FIG. 13 is an enlarged view of the gas supply unit of FIG.

FIG. 14 is a schematic view showing a driving method of a conventional gas supply unit.

FIG. 15 is a graph showing the effect of the distance between the sample surface and the gas nozzle on the gas pressure on the sample surface.

FIG. 16 is a view showing a cross-sectional shape of W embedded by FIB excitation CVD using a conventional method.

[Explanation of symbols]

 9 ... gas supply unit, 29 ... nozzle rotating device, 31 ... microscope, 36 ... current detection circuit, 42 ... thin plate, 46 ... control computer.

Claims (9)

[Claims] 1. A charged particle ion beam focused on a surface of a sample placed on a five-axis movable stage movable in an X-axis direction, a Y-axis direction, a Z-axis direction, a tilt direction, and a rotation direction. In a gas supply mechanism of a focused ion beam device that irradiates and etches the surface of the sample, a gas of a focused ion beam device characterized by comprising a gas nozzle that can be moved to an arbitrary position and is variable at an arbitrary angle Supply mechanism. 2. The gas supply mechanism for a focused ion beam device according to claim 1, further comprising a microscope for monitoring an angle of the gas nozzle in real time, and a control computer for adjusting the angle of the gas nozzle to an arbitrary angle. A gas supply mechanism for a focused ion beam device, comprising an angle adjusting means. 3. A charged particle ion beam focused on a surface of a sample placed on a five-axis movable stage movable in an X-axis direction, a Y-axis direction, a Z-axis direction, a tilt direction, and a rotation direction. A gas supply mechanism for a focused ion beam device that irradiates and etches the surface of the sample, comprising a current detection device that detects a minute current flowing between the surface of the sample and the tip of the gas nozzle. Gas supply mechanism for focused ion beam equipment. 4. A gas supply mechanism for a focused ion beam apparatus according to claim 1, wherein etching is performed while supplying an etching promoting gas from a high inclination angle to an arbitrary region on the surface of the sample. A gas supply mechanism for a focused ion beam device, characterized in that processing with an aspect ratio is enabled. 5. The gas supply mechanism for a focused ion beam apparatus according to claim 1, wherein the etching is performed on the surface of the sample while supplying an etching promoting gas from a high inclination angle, thereby forming a hole having a high aspect ratio. After processing the metal, the metal in the deposition gas is vapor-deposited in the hole while supplying the vapor deposition gas into the hole at a high inclination angle using FIB excitation CVD, whereby the metal is deposited in the hole. A gas supply mechanism for a focused ion beam device, wherein the gas supply mechanism can be reliably embedded. 6. A gas supply unit, a pipe detachably attached to the gas supply unit, a pipe angle adjusting device connected to a tip of the pipe and a rotation mechanism mounted on the gas supply unit. A gas supply mechanism for a focused ion beam device, comprising: 7. The gas supply mechanism for a focused ion beam device according to claim 6, wherein the pipe has flexibility. 8. The gas supply mechanism for a focused ion beam device according to claim 7, wherein an elastic body is wound around said pipe. 9. The gas supply mechanism for a focused ion beam device according to claim 6, wherein the pipe angle adjusting device is a thin plate.