JPH0652423B2 - Pattern defect repair device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for correcting a pattern defect of a semiconductor integrated circuit, a mask used in the semiconductor integrated circuit, or the like to be repaired.

[Conventional technology]

FIG. 2 is a schematic view showing an apparatus used for conventional mask pattern defect inspection and repair, in which (1) is a microfabrication product to be repaired, here the mask to be repaired, (2) a laser head, and (3). Is a laser beam emitted from the laser head (2), (4) is a lens for focusing the laser beam (3) on the mask to be modified (1), and (5) is a slit that determines the spot shape of the focused laser beam. Is. Although not shown in the figure, an optical system is provided using a half mirror or the like so that the periphery around this spot is in the visual field.

FIGS. 3 (a) and 3 (b) show the procedure for repairing a pattern defect portion using this apparatus, and FIG. 3 (a) is a pattern before repair,
(6b) is a corrected pattern, (7) is a protruding portion, (8) is a removed portion which is heated and evaporated by a laser beam spot, and (9) is a notched portion. Based on the result of the pattern defect inspection performed in advance, a pattern before correction, which has a protruding portion (7) as shown in FIG. 3 (a), is searched for, and the removed portion (8) surrounded by a dotted line is irradiated with a laser. By heating and evaporating and removing the protruding portion (7), a normal correction pattern (6b) as shown in FIG. 3 (b) was obtained.

[Problems to be solved by the invention]

The conventional pattern defect inspection / correction apparatus as described above was effective in the era when the pattern size was relatively large so far, but the pattern size is small (minimum width 1
However, there is a problem that the processing accuracy of the laser beam is relatively lowered and exceeds the allowable limit.

That is, FIG. 4 shows a case where the recent pattern size is modified by the conventional method described above, and a notch portion (9) may occur at a portion surrounded by a dotted line as shown in the drawing. This is due to the fact that the minimum alignment size and the laser beam spot diameter (several μm) become relatively large due to the use of an optical system, and the beam is generated when the protruding portion (7) is heated and evaporated by the laser beam. This is because the part removed by heat conduction also spreads to the uncovered part, but the variation in the spread width becomes a size that cannot be ignored.

In addition, Japanese Patent Application No. 59-207568 (Japanese Patent Application Laid-Open No. 61-84833) filed by the applicant proposes an apparatus for inspecting and correcting a defect of a mask pattern by using an ion beam.

However, in the one shown in this application, the inspection and the repair of the defect of the mask pattern are performed by the same ion beam, so that the normal pattern portion which does not need to be corrected by the scanning of the ion beam to know the defective portion is formed. There was a problem that damage was caused and the film thickness was thinned.

The present invention has been made in view of the above points, and obtains a device for reducing the reduction in the film thickness of the regular pattern portion of the article to be repaired by the ion beam when the ion beam is scanned to know the defective portion. The purpose is to

[Means for solving problems]

A pattern defect repairing apparatus according to the present invention receives an ion source that generates heavy ions and light ions, and receives both ions from the ion source, and outputs light ions when obtaining pattern information of an article to be repaired with a pattern, Ion selecting means for outputting heavy ions when the pattern of the article to be repaired is corrected, means for converging and scanning the ions from the ion selecting means into the pattern of the article to be repaired, and the article to be repaired irradiated with light ions Secondary emission based on light ions from
And a detection means for outputting the pattern information of the article to be corrected.

[Action]

In the present invention, the ion selection means selectively outputs light and heavy ions from the ion source that generates both light and heavy ions, light ions when obtaining pattern information of the product to be corrected, and heavy ions when pattern correction of the product is to be corrected. , The pattern information can be obtained without damaging the pattern portion that does not require correction or reducing the film thickness.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention,
(2a) is an ion source capable of controlling the ion beam current, and in this embodiment, an ion source that emits two types of light and heavy ions, (3a) is an ion beam composed of one of the two types of light and heavy ions, Reference numeral 4a) is a control electrode composed of a lens system for the ion beam (3a), a scanning system, etc., which is a means for converging the ions on the pattern of the mask to be corrected and scanning. (10) is a mass spectrometer that selects one of two types of light and heavy ions from the ion source (2a) and supplies it to the control electrode (4a), and (11) is the mask to be modified (1)
A stage for moving the scanning region of the ion beam (3a), (12) is an electron beam generated by the ion beam (3a) hitting the mask (1), and (13) is this electron beam (12). Detector to receive the light, (14) mask (1), control electrode (4a), stage (11)
And a mass spectrometer (10) containing a detector (13) and an ion source (2
Vacuum chamber connected to a) with vacuum piping, (15) is a mass spectrometer
(10) is an ion selection circuit for selecting one of both light and heavy ions, and constitutes ion selection means together with the mass spectrometer (10). (16) is an ion beam control circuit for the ion source (2a) and control electrode (4a), (17) amplifies the electron current of the detector (13), and masks (1) depending on whether or not a certain level is exceeded. The detection circuit that outputs a binary signal indicating whether or not the pattern portion of FIG. (18) is an electronic computer in which a fictitious logic circuit with three dotted frames realized by a program is operated in the order of the dotted arrows, and (19) finds the measured pattern of the mask (1). Observing means (20) compares the measured pattern (6a) corresponding to the conventional one shown in FIG. 3 with reference pattern data read in advance (various methods can be considered as a comparison method, but in the simplest case, the mask surface is There is a small number of cross-cuts, and there is a comparison for each of them.) Then, the protruding portion (7) is obtained, and the removed portion (8) including the protruding portion (7) and not including the reference pattern portion is removed. The removed portion extracting means for determining, and (21) is a correcting means for removing the protruding portion (7).

Next, the mask to be modified is
A method of correcting the defective portion in the pattern (1) will be described. First, the observation means (19) gives a logic signal to the ion selection circuit (15) so that the mass analyzer (10) selects a light ion, and a trigger to the ion beam control circuit (16). The circuit (16) controls the ion source (2a) and the control electrode (4a) so that the ion beam (3a) with a constant current strikes the ion beam scanning area on the mask (1) in the same manner as an ordinary cathode ray tube. It is like this. Further, the observation means (19) is from the detection circuit (17) to the ion beam (3a) via the detector (13).
By receiving a logic signal indicating whether the electron beam intensity generated by the ion beam exceeds a certain value at the same time from the ion beam control circuit (16), the logic signal indicating the position where the ion beam (3a) is hit is received. The presence / absence of a pattern at each position in the scanning area is stored in a memory and grasped as a measured pattern. Next, the removed portion extracting means (20) obtains the removed portion (8) as defined above and stores it in the memory. Finally, the correction means (21) provides a logic signal to the ion selection circuit (15) via which the mass analyzer (10) selects the heavy ions, and in the scanning area of the mask (1) this In the embodiment, an ion beam (3
The ion beam control circuit (16), the ion source (2a), and the control electrode (4a) are controlled to scan a).

In this embodiment, the light and heavy ions from the ion source (2a) are selectively output when the pattern information is obtained by the mass spectrometer (10) and when the pattern is corrected. Even if the size is small, the pattern information is obtained with the light ion beam, so accurate pattern information can be obtained without damaging the emmetropic pattern portion, and the pattern is corrected with the heavy ion beam. Therefore, heat diffusion does not occur unlike when a laser beam is used, and a correction pattern (6b) having no notch portion (9) as shown in FIG. 3 (b) is obtained.

In the above embodiment, the case where the required ion is selected and used by combining the ion source that simultaneously emits both the light and heavy ions and the mass analyzer has been described, but a separate ion source is prepared for each of the light and heavy ions and switched appropriately. May be.

In the above embodiment, the case where the correction process is continuously performed in the scanning region performed in the observation process is described, but the stage (11)
Alternatively, the observation step may be performed on the entire surface of the mask to be corrected (1) at a time, and the correction step may be the same.

Further, in the above embodiment, the case where the data related to the actually measured pattern obtained in the observation step is temporarily stored in the memory and then the extraction step is performed is described. However, the data may be sequentially processed without being stored in the memory. . That is, when the defect of the repaired mask (1) is repaired, the pattern information of the repaired mask (1) in the defective portion may be obtained and the defective portion may be repaired based on this pattern information.

Further, in the above embodiment, the case where two ion beams corresponding to both light and heavy ions are controlled by the same control electrode has been described, but a dedicated control electrode may be used for each.

Further, in this embodiment, the case where the ion beam composed of heavy ions is scanned only in the removed portion is described. However, the entire scanning region is scanned, and instead, the ion source (2a) is controlled to modulate the current of the ion beam. You may do it.

In the above embodiment, the case where the microfabricated product (1) is a mask has been described, but it can be applied to the pattern of each process of the wafer on which the semiconductor integrated circuit is formed. At this time, it goes without saying that it is necessary to correct the pattern of the process other than the correction target because it affects the electron beam intensity in the observation step and the ion etching rate in the correction step.

〔The invention's effect〕

As described above, the present invention selectively outputs light and heavy ions from an ion source that generates both light and heavy ions, light ions when the pattern information of the product to be corrected is obtained, and heavy ions when the pattern of the product is to be corrected. Since the ion selection means is provided, accurate pattern information can be obtained without damaging a pattern that does not require modification of the product to be corrected and without reducing the film thickness. There is an effect that the portion can be removed with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a schematic view of an apparatus used for conventional mask pattern defect repair, and FIGS. 3 and 4 are conventional pattern defect repair. It is a top view explaining a method. In the figure, (1) is the product to be modified, (2a) is the ion source, (3a) is the ion beam consisting of either light or heavy ions, (4) is the control electrode, and (10) is the ion selection means. A mass spectrometer, (12) an electron beam, (13) a detector, (19) an observing means, (20) a removed portion extracting means, and (21) a correcting means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An ion source for generating a heavy ion beam and a light ion beam, a means for selecting the heavy ion beam and the light ion beam, and an ion beam selected from the ion beam selecting means for focusing on an article to be repaired. Scanning means,
A control means for detecting secondary emission particles from the article to be corrected and outputting pattern information, and obtaining pattern information by irradiation of the light ion beam,
A pattern defect repairing device characterized by irradiating a heavy ion beam according to this pattern information to repair a pattern defect. 2. A pattern defect repairing apparatus according to claim 1, wherein a mass spectrometer is used as the ion beam selecting means.