JPS6259297B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for modifying a mask pattern, and particularly to a method for modifying a mask pattern using a collected ion beam.

(2) Background of the technology In recent years, with the miniaturization of various devices, the integration of internal devices, especially integrated circuits, has progressed, and the internal wiring width of integrated circuits is now a thin pattern of several microns. If a defect occurs during mask processing of this fine pattern, there is a need for a pattern repair method that can completely and accurately correct the defect.

(2) Prior art and problems If there is dust, etc. attached during the pattern drawing process, development process, and etching process in the pattern formation process on the mask, the dust is only attached to the part of the chromium Cr used to form the pattern on the soda glass. It remains on the board.

FIG. 1 is a diagram showing a case where chromium remains on soda glass. Conventionally, as a method for removing this residual chromium 1, an argon laser beam was applied to the residual chromium 1, and the residual chromium 1 was melted and removed by the heat of the laser beam.

However, as shown in Figure 2, effective pattern 2
If residual chromium 1 is present in contact with a part of
If an argon laser beam is applied to the residual chromium 1 and the residual chromium 1 is melted by the heat of the laser beam, a part of the effective pattern 2 will also be melted at the same time, making the effective pattern 2 thinner, and in some cases cutting the effective pattern 2. There was a risk that the residual chromium 1 would come into contact with the effective pattern 2 and remain, and it was impossible to correct it.

(3) Purpose of the Invention The present invention was made in view of the above drawbacks, and its purpose is to make it possible to remove only the residual chromium that has come into contact with the effective pattern, leaving the effective pattern completely intact. An object of the present invention is to provide a mask pattern correction method.

(4) Structure of the invention The purpose of the mask is to irradiate the edge of an effective pattern with a charged beam to separate the defective portion, and to remove the defective portion by irradiating the defective portion with a laser beam. This is accomplished by providing a pattern modification method.

(5) Embodiments of the Invention FIG. 3 is a block diagram of an apparatus for implementing the mask pattern correction method according to the present invention, and FIG. 4 shows the connection from the pulse generator 10 to the deflector 9 in the apparatus of FIG. It is a figure specifically shown.

In FIG. 3, an electron gun 5 for emitting an electron beam 4, a blanking member 6, a lens 7, and a deflector 9 for determining the position at which a sample 8 is irradiated with the electron beam 4 are provided in the column 3. Also, the deflector 9
A detector 12 is connected to the pulse generator 10 and detects secondary electrons 11 emitted from the sample 8.
is connected to the CRT display 13.

In FIG. 4, the output of pulse generator 10 is connected to the input of digital-to-analog converter 14, and the output of digital-to-analog converter 14 is connected to deflector 9 via buffers 15 and 16.

In the mask pattern correction method with the above configuration, the operation of removing residual chromium 1 existing in contact with the effective pattern 2 as shown in FIG. 2 will be described below.

First, the blanking 6 is turned on and the electron beam 4 is emitted from the electron gun 5 toward the sample 8 in order to make the CRT display 13 recognize the image. The electron beam 4 is focused through a lens 7, and is irradiated onto a predetermined position on a sample 8 by a deflector 9. A detector 12 detects secondary electrons 11 emitted from the sample 8 by irradiation with the electron beam 4, and outputs a detection signal from the detector 12 to a CRT display 13.

On the CRT display 13, the difference in brightness of the input signals is depicted depending on the input signals. The image on the CRT display 13 corresponds to the sample 8, and can be compared with the sample 8 in both position and size. Therefore, by visually observing the image on the CRT display 13, it is possible to accurately confirm the position of the irradiation section 17 that is to be irradiated with the beam shown in FIG. At this position, a collected ion beam of gallium Ga or the like is used to accurately cut the edge of the effective pattern 2, that is, the irradiation part 17, and make the residual chromium 1 stand up. For this purpose, the positions X ₀ , Y ₀ and sizes X ₁ , Y ₁ of the irradiation section 17 are input to the pulse generator 10 from an input device (not shown).

At this time, the pulse generator 10 also controls the dose amount for irradiating the irradiation unit 17 with the collected ion beam.
instruct. This dose increases in proportion to the number of scans, and the number of scans is set so that the dose is about 10 times the normal image forming time.

Next, the deflector 9 is controlled by the output signal of the pulse generator 10 into which the irradiation position, magnitude, and number of scans are input.

Beam irradiation is performed at the irradiation section 17 on the soda glass substrate.
In order to irradiate only the target area, the digital output from the pulse generator 10 is a signal that is collected at a fixed point on both axes. For example, when a 16-bit digital signal is input, the output signal is repeated so that only a certain position signal becomes high. Therefore, this repetitive signal is output from the pulse generator 10, and the digital-to-analog converter 14 converts this digital signal into an analog quantity. The output signal of the digital-to-analog converter 14 is amplified by buffers 15 and 16 to a voltage sufficient to deflect the electron beam 4, and a deflector 9 applies a voltage according to the output signal.

This deflector 9 causes the electron beam 4 to repeatedly irradiate the irradiation section 17 on the sample 8 with the electron beam a specified number of times and with a specified magnitude.

Therefore, residual chromium 1 connected to pattern 2
becomes an independent residual chromium 1 by removing the portion corresponding to the beam irradiation portion 17. Any remaining chromium 1 can be dissolved and removed using conventional argon laser beam irradiation equipment.

Therefore, as shown in Figure 2, the effective pattern can be narrowed or cut by irradiating the collecting beam along the regular position of the effective pattern even for residual chromium that is present in contact with the effective pattern. It can be precisely removed without any damage, and any residual chromium can be removed by a conventional laser beam.

The embodiments of the present invention are not limited to the above,
The signal input to the CRT display is compared with a standard pattern stored in advance, and this comparison signal output is input to the pulse generator, thereby displaying the image on the CRT display and at the same time causing the pulse generator to move to a predetermined position. It is also possible to automatically guide the charged beam to the defective part by inputting the size and dose signals.

(7) Effects of the Invention As described in detail above, according to the present invention, residual chromium that has come into contact with an effective pattern can be removed without fail while leaving the effective pattern, and the mask pattern can be reliably corrected. This has the effect of making it possible.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing that the effective pattern and residual chromium are separated, Fig. 2 is a block diagram showing that the effective pattern and residual chromium are in contact, and Fig. 3 is a mask according to the present invention. FIG. 4 is a partially detailed block diagram of the mask pattern repair method according to the present invention, and FIG. 5 is a block diagram showing separation of the effective pattern and residual chromium. 1... Effective pattern, 2... Residual chromium, 3...
...Column, 4...Electron beam, 5...Electron gun, 6
...Blanking, 7...Lens, 8...Sample,
9... Deflector, 10... Pulse generator, 1
1... Secondary electron, 12... Detector, 13...
CRT display, 14...Digital-to-analog converter, 15, 16...Buffer, 17...
Irradiation part.

Claims (1)

[Claims] 1. A method for correcting a mask pattern, which comprises irradiating an edge of an effective pattern with a charged beam to separate a defective portion, and removing the defective portion by irradiating the defective portion with a laser beam.