JPH0817385A - Focused beam device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a focused ion beam apparatus used for repairing a mask used in a semiconductor manufacturing process, repairing a wiring, and the like.
Alternatively, it is to efficiently supply a gas to a position where gas-assisted etching is performed and to perform processing and deposition efficiently. [Configuration] The overall configuration is an ion source (ion source 1, shield electrode 2, gun aperture 3), ion focusing system (focusing lens 4, aperture 5, scanning electrode 6, objective lens 7), gas supply system (nozzle 8, Heater 9, container 10, gas source 1
1, valve 12, fine movement device 13, valve knob 14),
It is composed of a sample fine movement device 16, a sample 18, a detector 15, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focused ion beam apparatus used for repairing masks and wiring used in semiconductor manufacturing processes.

[0002]

2. Description of the Related Art Conventionally, for example, as an ion beam assisted deposition apparatus, there is JP-B-2-25425, "Compound vapor spraying apparatus". This method is characterized in that a compound vapor having a relatively low vapor pressure is ejected in a beam shape using a nozzle. There is also a device in which a plurality of nozzles are arranged on the circumference so that the gas beam is ejected uniformly. If the vapor pressure of the workpiece is high, RIKEN 15th Symposium "Ion implantation and submicron machining" (1984)
As described in 121-124, a method is used in which the entire sample is covered with a gas and a small hole is provided only at the entrance of the ion beam.

[0003]

When the ejected gas is in the form of a beam, it is not coaxial with the ion beam, so that the position where the beam 17 hits the sample 18 cannot be confirmed as shown in FIG. Further, if the distance between the nozzle 8 and the sample 18 is large, the spread of the gas beam becomes large and the gas spraying efficiency may deteriorate. The distance between the nozzle 8 and the sample 18 needs to be as short as possible in order to improve the spraying efficiency, but this is a difficult technique to measure. Further, if the distance is too close, the sample 18 and the nozzle 8 may come into contact with each other, and the precious sample may be damaged. In the case of this structure, when the gas pressure distribution is measured, the point where the maximum pressure is reached is often located at the lower end of the nozzle, but this point is shaded by the upper end of the nozzle and the ion beam cannot be irradiated. Further, in the beam system of FIG. 3, the beam 17 may not reach a shadowed portion such as when the projection 21 is formed on the sample surface or when the hole 22 is formed in the sample.

[0004]

[Means for Solving the Problems] A nozzle 8 having two outlet small holes 20, a fine movement device 13 for moving the nozzle three-dimensionally in X, Y, and Z, for supplying gas to the small holes 20. Means, a means for moving the sample so that the processed portion of the sample 18 becomes the center of the small hole, a means for irradiating a beam to the processed portion of the sample, and the like.

[0005]

As shown in FIG. 2, the point that is basically different from the conventional one is that the gas is not applied to the sample in the form of a beam, but the upper and lower parts
The gas is spouted randomly from one small hole 20 around this hole. The distribution of gas follows molecular kinetic theory. The gas emitted from the lower small holes collides with the sample 18 and is partially adsorbed under the conditions described by the surface physics. When the high-energy beam 17 (ions) collides with the particles, the interaction between the particles and the sample 18, and the gas adsorbed to the part, causes metal deposition on the sample surface, etching by sputtering or chemical reaction, etc. Occurs.

[0006] What is important here is how to efficiently supply the gas to the processing portion, and in order to achieve this, the position of the nozzle 8 is set correctly. Here, the position (X, Y) of the small hole is the scanning ion image (SIM), and the Z position is S under the condition of the objective lens calculated in advance.
This is accomplished by focusing the IM image on top of the nozzle. In this case, it is necessary to know the thickness of the nozzle 8 and the lens characteristics in advance. It is also important that the upper surface of the nozzle 8 is flat to the extent necessary for the above alignment.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings. FIG. 1 shows an embodiment applied to tungsten deposition in a focused ion beam apparatus. The overall configuration is an ion source (ion source 1, shield electrode 2, gun ahercha 3), ion focusing system (focusing lens 4, aperture 5, scanning electrode 6, objective lens 7), gas supply system (nozzle 8, heater 9, container) 10, gas source 11, valve 12, fine movement device 13, valve knob 14), sample fine movement device 16, sample 18, detector 1
It is composed of 5 etc.

Next, the operation will be described. Ga ions emitted from the ion source are accelerated to 30 kV and focused on the sample 18 by the focusing lens 4 and the objective lens 7. This beam is scanned by the scanning voltage applied to the scanning electrode 6,
At this time, the secondary electrons emitted from the sample 18 are detected by the detector 15
The signal is recorded as an image (scanning ion image: SIM image). On the other hand, the gas source 11 in the container 10 uses hexacarbonyl tungsten (W (CO) ₆ ) in this case, and is heated to about 50 degrees by the heater 9. In this state, solid W (CO) ₆ sublimes and maintains a vapor pressure of about 50 Pa. In this state, when the valve knob 14 is turned to open the valve 12, the W (CO) ₆ gas passes through the nozzle 8 and is ejected from the small hole 20. The gas ejected from the small holes on the lower side is adsorbed by the sample 18, where it collides with Ga and W
And W are decomposed into CO ₂ and only W is deposited there. In order to deposit efficiently, it is important to supply W (CO) ₆ gas efficiently, and in this case, the small hole 20 is the beam 1
It is at the center of 7 and the distance between the nozzle 8 and the sample 18 should be as close as possible without damaging the sample. A method of determining this condition will be described with reference to FIG. First, the scanning range of the SIM image is set to about 1 mm, and the portion to be processed is adjusted to the center of the image by using the sample fine movement device. For example, in FIG.
When W is embedded in the cross hole as in (a), the center of this hole is moved to the center of the image. Next, the center of this hole and the small hole 20
X and Y of the gas-system fine movement device 13 so that the centers of
To adjust. Next, the voltage of the objective lens 7 is increased to a value calculated in advance, and it is confirmed that the upper surface of the nozzle 8 can be clearly seen at this point (FIG. 4B). If it is not clear, the Z of the fine movement device 13 is adjusted. The position adjustment of the nozzle 8 was confirmed by the above adjustment. Such adjustment is impossible with the conventional nozzle as shown in FIG. Further, since the upper and lower sides of the nozzle 8 are parallel when adjusting the Z position, there are the following two advantages. That is, if the upper surface of the nozzle is flat, it is easy to focus, and if the lower surface is flat, the sample is less likely to be damaged even if it touches the sample 18. Since the surface area is large when the lower surface of the nozzle is flat, it is relatively easy to measure the capacity between the nozzle and the sample, and the distance between the sample nozzles can be measured using this principle. Another advantage of this nozzle is that the sample processing part and the gas ejection small hole 2
Since 0 is concentric, it is possible to deposit the gas beam uniformly without producing a shadow of the gas beam. This structure is very important when filling deep holes with W.

Further, it has been confirmed that if the small hole as shown in FIG. 2 is near the sample, the sample does not charge up relatively even if the sample is an insulator. When the small holes were filled with gas, charge-up was less likely to occur, and the side effect of the nozzle with this structure was confirmed.

FIG. 5 shows an embodiment of the nozzle 8. In this case, one end of a thin pipe is crushed to be flat, the end face of the flat portion is pressed and sealed, and a small hole 20 is opened at the center of the flat portion. The machining of small holes is performed by electrical discharge machining with little deformation. The diameter of the small holes in this case is 1 mm. The reason for setting the diameter of the small hole to 1 mm was determined based on the conditions that it was larger than the maximum processing range and was as small as possible, and that it was smaller than the maximum scanning range for positioning. The smaller the diameter of the small hole, the more efficiently the gas can be ejected, but when the secondary particles emitted from the sample are detected through this small hole, it is advantageous that the diameter is as large as possible in comparison with the thickness of the nozzle. Taking these things into consideration, the diameter of the small holes was determined.

Considering that the small holes make it difficult for the secondary particles to be pulled out from the sample surface to the detector, a positive or negative voltage can be applied to the small holes. A positive voltage is applied to extract secondary electrons, and a negative voltage is applied to positive ions. The voltage varies depending on the conditions, but about 100 V is sufficient.

Although the deposition of W by an ion beam has been described in the above embodiments, the present invention can also be applied to an ion beam assisted etching technique. That is dissociated Xe and F ₂ by the ion beam when the same operation by introducing instead XeF ₂ of W (CO) ₆ in the container 10 for locally etching F _2, for example, the Si of this. In this case, it is known that the effect of sputtering by ions and the effect of etching by F ₂ are overlapped, and the processing speed is about 10 times faster than the case of only ions. When such processing is performed, the same effect as in the case of W deposition can be obtained.

The present gas introduction system is also useful when deposition or processing is performed by using a laser as the primary beam.

[0014]

According to the present invention, the following effects are obtained.

(1) Since the position of the gas nozzle can be accurately adjusted, the processing conditions can be accurately determined.

(2) Since it is difficult to form shadows due to gas ejection, uniform processing is possible and deep holes can be handled.

(3) Since the nozzle and the sample are parallel to each other, the sample is less likely to be damaged during the adjustment.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of the present invention.

FIG. 2 is an enlarged view of a small hole portion of the present invention.

FIG. 3 is a diagram for explaining a nozzle portion of a conventional technique.

FIG. 4 is a diagram for explaining a method of adjusting a nozzle position.

FIG. 5 is a diagram illustrating an example of a nozzle unit.

[Explanation of symbols]

1 ... Ion source, 2 ... Shield electrode, 3 ... Gun ahercha, 4 ... Focusing lens, 5 ... Aperture, 6 ... Scan electrode,
7 ... Objective lens, 8 ... Nozzle, 9 ... Heater, 10 ... Container, 11 ... Gas source, 12 ... Valve, 13 ... Fine movement device, 1
4 ... Valve knob, 15 ... Detector, 16 ... Sample fine movement device, 17 ... Primary beam, 18 ... Sample, 19 ... Gas, 20
... small holes, 21 ... projections, 22 ... holes.

Claims (6)

[Claims] 1. A device capable of performing beam-assisted etching or beam-assisted deposition using a focused beam device, wherein gas is made to flow out from both ends of a small hole arranged at the center of the beam and one end of the small hole is processed. A focused beam device in which an object is placed and processing is performed by a beam penetrating a small hole. 2. The focused beam device according to claim 1, wherein the inner diameter of the small hole is within the beam scanning range. 3. The focused beam apparatus according to claim 1, wherein the position of the small hole is movable from outside the vacuum. 4. The focused beam device according to claim 1, further comprising a function of measuring a distance between the position of the small hole and the sample. 5. The focused beam apparatus according to claim 1, wherein the small hole has a structure in which a pipe-shaped portion is crushed to be flat, and the small hole is provided at a right angle to the flat portion. 6. The focused beam device according to claim 1, wherein a voltage can be applied to the small hole portion.