JPH11132755A - Length measuring method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the length of a semiconductor device having a high aspect ratio with high precision. SOLUTION: An electron beam 2 is scanned in the scope of an electron beam scanning width 4 which is controlled by a scanning circuit part 3 and has a known width from an electron beam part 1. When a sample is irradiated with the electron beam 2, characteristic X ray 5 is generated from the irradiated measuring points 9, 10, 11, 12 and is detected by a characteristic X ray detection part 6. At this time, peaks of the characteristic X ray detected from each measuring point differ depending on constituent elements of the measuring points 9, 10, 11, 12. A length of a semiconductor device is measured by detecting change points of this characteristic X ray in the electron beam scanning width 4 which is the known width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring the length of a semiconductor device with high accuracy, and more particularly to a method for measuring the length of a bottom of a semiconductor device with a high aspect ratio with high accuracy.

[0002]

2. Description of the Related Art In recent years, the number of steps for determining the shape after processing by measuring the length of a semiconductor device using an electron beam after the fine processing step of the semiconductor device has increased.

In a conventional method for measuring the length of a semiconductor device, an electron beam is scanned over a semiconductor device, secondary electrons generated from a scanned point are detected, and secondary electrons generated from a difference in secondary electron generation efficiency are detected. The method of measuring the length using a profile was used.

[0004]

However, in the above-mentioned conventional method, when measuring the bottom of a semiconductor device having a high aspect ratio, it is difficult to detect secondary electrons from a point scanned by an electron beam, so that measurement is performed with high accuracy. It was difficult to prolong.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. In particular, the present invention relates to a semiconductor device capable of accurately grasping the shape of the bottom by accurately measuring the length of the bottom of the semiconductor device having a high aspect ratio. It is intended to provide a length measuring method.

[0006]

In order to achieve the above object, a semiconductor device length measuring method according to the present invention scans an electron beam on a semiconductor device and detects the difference based on a difference in material generated from the scanned point. This is a method of measuring the length by detecting characteristic X-rays having different peaks.

According to this method, in measuring the length of the bottom of a semiconductor device having a high aspect ratio, which has conventionally been difficult, a characteristic X-ray having a characteristic in which a peak detected due to a difference in substance is different from each other is detected. Since a change in the length can be accurately detected, it is possible to realize a length measuring method with higher accuracy than before.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a method for measuring the length of a semiconductor device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an electron beam portion, 2 denotes an electron beam, 3 denotes a scanning circuit portion for scanning the electron beam 2, and 4 denotes an electron beam scanning width. 5
Is a characteristic X-ray generated from the sample by irradiating the electron beam 2, 6 is a characteristic X-ray detector, 7 is a resist film, and 8 is bare silicon. Here, the contact hole pattern is formed on the bare silicon 8 by the resist film 7. Reference numerals 9, 10, 11, and 12 are measurement points at which the characteristic X-ray 5 is detected by scanning the electron beam 2.

In this embodiment, first, the electron beam 2 is scanned from the electron beam section 1 to the electron beam scanning width 4 of a known width controlled by the scanning circuit section 3. When the sample is irradiated with the electron beam 2, characteristic X-rays 5 are generated from the irradiated measurement points 9, 10, 11 and 12, and are detected by the characteristic X-ray detector 6. At this time, the peak of the characteristic X-ray detected from each measurement point is measured at the measurement points 9.1 and 9.1.
It differs depending on the constituent elements 0, 11, and 12. In the electron beam scanning width 4 which is a known width, the length measurement is performed by detecting the changing point of the characteristic X-ray.

This will be described in detail. FIG.
Are the measurement points 9, 10, 1 detected by the method of FIG.
It is a peak figure of the characteristic X-ray in 1 and 12. In FIG. 2, FIG. 2A is a characteristic X-ray peak diagram at measurement points 9 and 12, and FIG. 2B is a characteristic X-ray peak diagram at measurement points 10 and 11.

FIG. 3 is a signal showing a change in the peak of the characteristic X-ray shown in FIG. In FIG. 3, reference numeral 13 denotes a signal width at a change point of the peak of the characteristic X-ray.

The operation of the method for measuring the length of the semiconductor device according to the present embodiment configured as described above will be described below.

The electron beam 2 is scanned from the electron beam 1 to the electron beam scanning width 4 of a known width controlled by the scanning circuit 3.

Here, the scanning direction is the direction from the measuring point 9 to the measuring point 12. First, a characteristic X-ray peak as shown in FIG. Since the constituent material at the measurement point 9 is the resist film 7, the peak of the characteristic X-ray is C,
O and Si show great strength. Next, at the measurement point 10 or the measurement point 11, a characteristic X-ray peak as shown in FIG. 2B is obtained. Since the constituent material at the measurement point 10 or the measurement point 11 is the bare silicon 8, the peak of the characteristic X-ray shows a large intensity in Si. Further, from the measurement point 12, a characteristic X-ray peak as shown in FIG. Since the constituent material of the measurement point 12 is the resist film 7,
The characteristic X-ray peak shows a large intensity for C, O, and Si.
When a change in the peak of the characteristic X-ray at the measurement points 9, 10, 11, 12 is signal-processed, a change in the signal as shown in FIG. 3 is obtained. In FIG. 3, since the electron beam scanning width 4 is a known width, the measured value of the bottom of the contact hole pattern formed by the resist film 7 on the bare silicon 8 can be obtained by the following equation.

Measurement value = (known width) × (signal width of peak change point of characteristic X-ray 13 / electron beam scanning width 4) As described above, according to the present embodiment, the electron beam is scanned. By capturing the change of the characteristic X-ray peak generated from the point, it is possible to measure the length very accurately in a semiconductor device having a high aspect ratio.

[0016]

As described above, according to the present invention, a semiconductor device is scanned with an electron beam, and a characteristic X-ray generated from a scanned point and having a characteristic in which a peak detected due to a difference in substance differs from one another is detected. And a highly accurate semiconductor device length measuring method capable of accurately detecting the length.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a method for measuring a length of a semiconductor device according to an embodiment of the present invention;

FIG. 2 is a characteristic X-ray peak diagram in a semiconductor device length measuring method according to an embodiment of the present invention.

FIG. 3 is a signal diagram showing a change in a characteristic X-ray peak in a semiconductor device length measuring method according to an embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron beam part 2 Electron beam 3 Scanning circuit part 4 Electron beam scanning width 5 Characteristic X-ray 6 Characteristic X-ray detection part 7 Resist film 8 Bare silicon 9, 10, 11, 12 Measurement point 13 Characteristic X-ray peak change point Signal width

Claims (1)

[Claims] 1. A semiconductor device that scans an electron beam with a semiconductor device, synchronizes a characteristic X-ray peak generated from the semiconductor device with a scanning position, and measures a length of the characteristic X-ray by capturing a change in the characteristic X-ray peak. A length measuring method for a semiconductor device, comprising: