JPH0224949A - Locating device for device processing with focused ion beam - Google Patents

Abstract

PURPOSE:To provide a location alignment device easy to define the processing zone by furnishing an optical microscope, image display device, stage moving device, and operation command means of beam irradiation optical system. CONSTITUTION:A parallel pattern 17 is processed on a metal film band 18. At this time, the mouth of a computer 16 is operated on the image of a display device, and a film-equipped part is specified. The computer 16 drives a stage moving device 11, and a stage 2 is moved for a distance corresponding to the interaxis distance of a microscope 12 and an ion beam irradiation optical system. Then the ion beam irradiation optical system 4 is operated according to the stored information in the computer 16, and focused ion beam is projected only onto the processing zone. The number of picture elements in the X and Y directions in the image zone is made equal to the max. input value to a D/A converter 20, and the length between picture elements on display device 6 is made the same as the beam motion length at one step of the D/A converter. A deflection signal is delivered from the computer 16 through a control circuit 21, A/D converter 20, and amplifier 22, and thus a deflection plate 19 is driven. Accordingly the processing zone can be defined easily and quickly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for processing and modifying devices such as semiconductor ICs using a focused ion beam, and particularly relates to an alignment apparatus for aligning the processing position on the device. .

[Summary of the Invention] An optical microscope is provided near a focused ion beam device in order to improve and advance pattern film processing and defect correction technology as semiconductor devices (LSI) have become larger and more highly integrated in recent years. On the other hand, an image display device that digitally displays an image of an optical microscope via a photoelectric conversion element, and a stage that moves the X-Y stage between the optical axis of the ion beam irradiation optical system and the optical axis of the optical microscope. a mobile device;
a specifying means for activating the ion beam irradiation optical system so as to irradiate only the processing area of the device specified on the display of the image display device, and observing and searching for processing parts and defective parts with an optical microscope; During processing or defect correction, the device was moved and processed using an ion beam irradiation optical system.

[Prior Art] One of the reasons why semiconductor devices have become larger and more highly integrated in recent years is the remarkable development of semiconductor device manufacturing technology. One of the semiconductor device manufacturing techniques is the so-called FIB technique. This FIB technique is a technique for enlarging and describing and observing the surface of a semiconductor element, and also serves as a technique for processing and correcting a pattern drawn on this semiconductor element.

An outline of this FIB technology is shown in FIG. A device to be processed (for example, a semiconductor element) 1 is placed on an X-Y stage 2
will be placed on. This XY stage 2 is configured to be movable within a plane perpendicular to the optical axis of the focused ion beam to be irradiated. The XY stage 2 and the device 1 are housed in a vacuum chamber 3. In this vacuum chamber 3, a predetermined compound gas is blown by a gas gun (not shown), and in this compound gas atmosphere, a focused ion beam is irradiated onto the processing area on the device 1 by an ion beam irradiation optical system 4. By this irradiation, for example, missing portions of the pattern on the surface of the device 1 can be filled.

At this time, in order to discover defective parts such as missing parts,
Conventionally, first, the surface of the device 1 is detected by the ion beam with the focused ion beam device in observation mode, and this detection signal is led to the image display device 6 to form an image of the device surface, and processing is performed on the formed image. A region to be processed is designated, and then the focused ion beam device is set in processing mode to irradiate only the designated region with the focused ion beam. At this time, the designation and the control of the ion beam irradiation optical system were performed by the designation means 7.

[Problem to be Solved by the Invention] However, according to the above-mentioned prior art, when an image is formed on the surface of a device, the image is also generated from the surface of the protective film which is the device, and the image formed thereby is caused by unevenness on the surface of the protective film. The contrast caused by this will be added. For this reason, it was often impossible to accurately observe the pattern of the protected inseam.

Conventionally, in such cases, the area to be processed and corrected is determined based on the pattern of the design data from pattern images of other parts that can be observed accurately, and the optical axis of the ion beam is aligned with the determined processing area. X-Y stage 2 was being moved. For this reason, the operation for aligning the processing area and the optical axis of the ion beam becomes complicated and time-consuming.

In addition, in order to find a region to be processed and corrected, it is necessary to irradiate the ion beam onto a portion of the surface of the semiconductor element other than the processed region, which may cause damage to the semiconductor device.

This invention has been made in view of the above problems, and aims to provide an alignment device that allows easy determination of a processing area and eliminates the need to irradiate unnecessary parts of a device with an ion beam. .

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an optical microscope near the ion beam irradiation optical system of a focused ion beam device, and transmits an image of the optical microscope through a photoelectric conversion element. The X
- a stage moving device for moving the Y stage; and a specifying means for operating the ion beam irradiation optical system so as to irradiate only the processing area of the device specified on the display of the image display device. This is a summary.

[Function 1] Since the light from the optical microscope passes through the protective film, the formed image can clearly show the pattern under the protective film. Furthermore, the light from an optical microscope does not illuminate the device like an ion beam.

Therefore, a defective portion of the device is detected by safely and reliably observing the device using an optical microscope. After this defect position is memorized, the X-Y stage is driven to move the device between the optical microscope and the ion beam irradiation optical system.

Thereafter, the ion beam irradiation optical system irradiates the defective portion of the device with a focused ion beam to perform processing such as defect correction.

[Example] FIG. 1 shows an example of the present invention. Note that the same parts as in FIG. 3 showing the conventional example are given the same numbers and the description thereof will be omitted. A device 1, which is a workpiece placed on the XY stage 2, is a semiconductor element. First, before processing correction is performed, the X-Y stage 2 is driven by the stage moving device 11, and the device 1 is moved to the optical microscope 1.
Located below 2. The image captured by the optical microscope 12 is converted into an electrical signal by a photoelectric conversion element 13 such as a COD camera. This electrical signal, or video signal, is
It is converted into a digital signal by an AD (analog-to-digital) converter 14. Thereafter, it is guided to the image memory 15, and image data based on the digital signal is stored therein. The computer 16 reads this stocked image data as a digital signal, transfers it to the video memory inside the computer 16, and displays it on the image display device 6. Thereby, the image obtained by the optical microscope is displayed on the image display device 6.

An example of an image showing the processing area found by the image display device 6 is shown in FIG. In this figure, part of the pattern is
It appears as two pattern portions 17 that are parallel to each other. Let us now consider the case where processing correction is performed to connect these two pattern portions 17. When processing or modifying a metal film by forming a metal film, such as the band 18 in the center of the figure, first place the metal film on the area on which the metal film is to be applied by operating the computer 16's mouse over the image on the image display device. (The band in the center of the figure) is specified.

This designation is performed, for example, by drawing a frame surrounding the outer periphery of the band using a mouse. Since this frame is generally generated through software, the computer 16 can know the positions of all points in this frame.

When processing this processing area, the computer 16 first drives the stage moving device 11 to move the XY stage by the distance between the optical axis of the optical microscope 12 and the optical axis of the ion beam irradiation optical system 4. Move 2. This distance is fixed and precisely defined. After this movement is performed, according to the information of the frame stored in the computer 16, only the inside of this frame (processing area only) is processed.
The ion beam irradiation optical system 4 is operated to irradiate with a focused ion beam. This operation is performed by correctly controlling the voltage of the deflection plate 19 provided in the X and Y directions of the ion beam irradiation optical system 4. For correct control, for example, the number of pixels in the X and Y directions of the image display area of the image display device and the maximum digital input values of X and Y of the D/A converter 20 that controls the deflection plate 19 are made equal. In addition, the length between pixels of the image on the image display device 6, the amount of change of the ion beam controlled by one step of the D/A converter, and the length of movement on the device are made equal.

Then, the computer 16 sends the position coordinate data of the frame to the scan control circuit 21.
1 sends a digital scanning signal to the D/A converter 20 so as to irradiate only the inside of the frame with the ion beam. This scanning signal is amplified by the deflection amplifier 22 and guided to the deflection plate 19.

[Effects of the Invention] Light from an optical microscope can pass through the protective film and accurately capture the pattern of the protected inseam to form an image. As a result, contrast due to unevenness on the surface of the protective film does not appear in the image as in the conventional case, and the processing area can be easily determined. Therefore, it takes a short time to determine the machining area.

Furthermore, the light from the optical microscope does not damage the surface of the device, and the ion beam can be irradiated only to the defined processing area.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the processing alignment apparatus for a device processed by an ion beam according to the present invention;
FIG. 2 is a diagram showing an example of an image displayed on the image display device 6 to represent the operation of FIG. 1, and FIG. 3 is a block diagram showing a conventional device. 1...device, 2...X-Y stage, 3...
To vacuum, 4...Focused ion beam irradiation system, 5...2
Next ion detector, 6... Image display device, 7... Specifying means, 11... Stage moving device, 12... Optical microscope, 13... Photoelectric conversion element, 14... A-D Converter, 15... Image memory, 16... Computer,
17... Pattern portion, 18... Band, 19... Deflection plate. Patent applicant: Seiko Electronic Industries Co., Ltd. Agent
Patent Attorney Keinosuke Hayashi Figure 2

Claims (1)

[Claims] An X-Y stage on which a device to be processed is mounted, an ion beam irradiation optical system that irradiates the device with a focused ion beam in a predetermined compound gas atmosphere, and an optical microscope provided near the ion beam irradiation optical system. an image display device that digitally displays an image of an optical microscope via a photoelectric conversion element; and a stage that moves the X-Y stage between the optical axis of the ion beam irradiation optical system and the optical axis of the optical microscope. A device processing positioning apparatus using a focused ion beam, comprising: a moving device; and a specifying means for operating the ion beam irradiation optical system so as to irradiate only the processing region of the device specified on the display of the image display device. .