JPH081794B2 - Ion beam processing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ion beam irradiation processing method for irradiating an object with an ion beam while scanning and observing and processing a minute region. Specific examples thereof include a defect repair processing method for a semiconductor manufacturing mask, but the method is not limited to this.

B Outline of the Invention The present invention is an ion beam irradiation apparatus for irradiating an object to be processed while scanning with an ion beam to perform fine observation and fine processing. The ion beam scanning direction is appropriately selected according to the arrangement relationship of the object pattern. By making it possible,
The observation image of the fine pattern can be made clear and the precision of the fine processing can be improved.

C Related Art As a conventional ion beam irradiation apparatus, there has been known a conventional ion beam irradiation apparatus that performs raster scan scanning of an ion beam because the ion beam irradiation apparatus always moves downward from upper left to right.
Then, secondary charged particles emitted from the surface of the workpiece corresponding to the scanning of the ion beam are detected at every moment and computer processing is performed to reproduce a fine pattern image of the surface of the workpiece.

D Problem to be Solved by the Invention However, there is a problem in that the conventional ion beam irradiation apparatus in which the scanning direction is fixed cannot accurately reproduce the fine pattern on the surface of the workpiece.

For example, in FIG. 4A, the pattern of the ion beam scanning range 1 may be composed of the substrate surface 2 on the left half and the metal surface 3 on the right half. It is now assumed that the ion beam scanning is always performed from left to right. The surface of the insulator is charged while the ion beam passes through the substrate surface 2 which is the insulator. As a result, when the ion beam 4 passes through the boundary line 5, detection of secondary charged particles is disturbed, and the reproduced image of the boundary line becomes unclear.

Further, as shown in FIG. 4B, when the ion beam 4 is scanned in a direction away from the detector 6, secondary charged particles emitted from the boundary line 5 between the metal surface 3 and the substrate surface 2 are effectively detected. Instead, the reproduced image may become unclear.

E Means for Solving Problems The present invention aims to solve the above problems of the prior art.

That is, the ion beam irradiation control apparatus is provided with an ion beam scanning control means capable of appropriately selecting the scanning direction of the ion beam in accordance with the shape and orientation of the fine pattern to be observed.

F Action The action of the present invention will be described with reference to FIG. 4 again. In FIG. 4 (A), the scanning direction of the ion beam 4 is selected from right to left. Initially, the metal surface 3 is irradiated with the ion beam, but the electric charge provided by the ion beam moves on the metal surface 3 and is not charged. Therefore, when the ion beam passes through the boundary line 5, there is no influence of charging and detection of secondary charged particles by the detector cannot be obstructed.

Further, in the case of FIG. 4B, the scanning direction of the ion beam 4 is selected from the right to the left toward the detector 6 to increase the detection efficiency of secondary charged particles.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram of an ion beam irradiation apparatus according to the present invention.

An ion source 7 emits an ion beam 4. A scanning electrode 8 is composed of two sets of X and Y electrodes for raster-scanning the ion beam 4 in the X and Y directions. An objective lens 9 focuses the ion beam on the plane of the workpiece 10. Reference numeral 11 denotes an XY stage on which the workpiece 10 is placed and the workpiece is moved to a desired position. 12
Is a gas gun for spraying an acid-containing compound vapor on the surface of the object to be processed and baking it with the ion beam 4 to form a film. A detector 13 detects the intensity of secondary charged particles 14 (for example, secondary electrons or secondary ions) emitted from the surface of the workpiece 10 by the irradiation of the ion beam 4.

Reference numeral 15 is an ion beam scanning control circuit, which is a circuit for controlling the operation of the scanning electrode 8.

The ion beam scanning control circuit 15 includes a scanning direction designating circuit 16
And the output of the scanning range designation circuit 17 is input. The scanning direction designating circuit 16 sets the scanning direction of the ion beam by manual operation. In this embodiment, as will be described later, eight different scanning directions can be selected according to the pattern arrangement of the workpiece and the relative positional relationship with the detector. The scanning range designation circuit 17 specifies a desired minute range of the workpiece 10 by manual operation and sets a range to be observed or processed by ion beam scanning.

Reference numeral 18 denotes an ion beam scanning circuit, which is controlled by the ion beam scanning control circuit and supplies an operating voltage to the scanning electrode 8 via the OR gate 19. Ion beam scanning circuit 18
Has eight terminals a to h, each of which selectively supplies an operating voltage as shown in FIG.
The waveform in FIG. 2a is for the most basic raster scan, in which the spot of the ion beam is scanned from left to right on the XY plane, and the scan lines are sequentially moved from top to bottom.
In the case of b, the slope of the voltage applied to the Y electrode (hereinafter referred to as the Y waveform) is opposite to that of a. Therefore, the spot of the ion beam moves from left to right on the XY plane, and the scanning lines sequentially move from bottom to top. Similarly, in C, the ion beam spot moves from right to left, contrary to a, and the scanning line which is the locus of the spot moves from top to bottom. In d the spots move from right to left as in C and the scan lines move from bottom to top. e, f, g and h are the a and b, c and d with the X and Y waveforms interchanged, the ion beam spot moves up and down, and the scanning line which is the locus of the spot is sequentially moved to the left and right. Move in either direction. In response to the output of the ion beam scanning control circuit 15, the ion beam scanning circuit 18 supplies one set of XY waveforms a to h to the scanning electrode 8 via the OR gate 19. Therefore, the operating direction of the ion beam 4 can be appropriately selected.

Next, the detector 13 detects the intensity of the secondary charged particles 14 sequentially generated by the scanning of the ion beam. The detected data is converted into bit data by the A / D converter 20 and stored in the pattern storage circuit 21 as a bit map. In accordance with this bit map, a fine pattern image of a predetermined range of the workpiece 10 is reproduced on the display device 22. At this time, the display device 22 uses a cathode ray tube of an electron beam raster scan system.
The display drive circuit 23 for raster scanning the electron beam is synchronized with the output of the ion beam scanning circuit 18. Therefore, an actual pattern image of the workpiece 10 and a pattern image similar to the enlarged image are faithfully reproduced by the same scanning method.

FIG. 3 is an overall configuration diagram showing another embodiment of the present invention. The same numbered parts as in FIG. 1 perform the same functions. The intensity analog data of the secondary charged particles 14 detected by the detector 13 is amplified by the amplifier 24 and then digitally converted by the A / D converter. Converted to data. The digital bit data is fetched by the CPU 25 in time series and then stored on the bit map of the video RAM 26. Next, the CPU 25 reads the digital bit data from the bit map according to the instruction when it is input to the scanning direction designating circuit 16, supplies it to the display device 22, and reproduces the pattern image. At this time, if the ion beam scanning is performed from left to right and it is instructed to move the scanning line, which is the trajectory of the ion beam, from top to bottom, the digital map data can be read from the bit map by the bit map. Start from the upper left point and move to the right. Then, it moves to the lower stage. In this way, the pattern of the workpiece 10 is
Regardless of the scanning direction of the ion beam, it is always faithfully reproduced as a similar solid. The CPU 25 creates a digital scanning waveform according to the input of the scanning direction designating circuit 16 and supplies it to the data register 27. The digital data of the data register 27 is converted into an analog voltage value by the D / A converter 28 and applied to the scan electrode 8 as an operating voltage. As a result, a desired ion beam scanning direction can be set.

H Effect of the Invention As described above, according to the present invention, the positional relationship of the patterns on the surface of the workpiece (that is, the combination of the insulator pattern and the metal surface pattern), the relative surface of the workpiece and the detector. Since the scanning direction of the ion beam can be appropriately selected according to the positional relationship, the adverse effect of ion beam charging on the workpiece can be eliminated, and the sensitivity of the detector can be increased.
There is an effect that the observation image of the fine pattern becomes clear and the fine processing precision is improved.

Further, since the reproduced image of the pattern always corresponds to the actual orientation of the workpiece pattern regardless of the difference in the scanning direction of the ion beam, there is an effect that the image analysis can be performed very easily.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an ion beam irradiation apparatus according to the present invention, FIG. 2 is a waveform diagram of an ion beam scanning electrode applied, and FIG.
FIG. 4 is an overall configuration diagram of another embodiment, and FIG. 4 is a diagram showing a conventional ion scanning method. 7 ... Ion source 8 ... Scan electrode 13 ... Detector 15 ... Ion beam scan control circuit 16 ... Scan direction designation circuit 18 ... Ion beam scan circuit 22 ... Display device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Aida 6-31-1, Kameido, Koto-ku, Tokyo Seiko Denshi Kogyo Co., Ltd. (56) Reference JP-A-52-55374 (JP, A)

Claims (3)

[Claims] 1. A surface of a workpiece on which an insulator and a conductor are formed is irradiated with an ion beam while being raster-scanned by an ion beam scanning circuit, and is generated from the surface of the workpiece by the irradiation of the ion beam. The secondary charged particles are detected by a detector, the pattern of the workpiece is displayed on a display device according to the output from the detector, and the raster is obtained by arranging an insulator and a conductor on the surface of the workpiece. An ion beam processing method characterized by selecting a scanning direction of scanning. 2. The scanning direction of the selected raster scan is
The ion beam processing method according to claim 1, wherein the scanning direction is from the conductor direction to the insulator direction. 3. The ion beam processing method according to claim 1, wherein the object to be processed is a mask for manufacturing a semiconductor.