JPS63308909A - Defect observing method for semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a method to find out accurately and easily a part to be re-observed, by supplying a gas containing metal compound, irradiating, via the gas, the vicinity of a part to be observed with a converged ion beam when output energy is adjusted, and forming a metal mark thereon. CONSTITUTION:When the part 2 to be observed of a semiconductor device 1 to be observed is irradiated with primary ion beam 3, secondary electron 4 is excited and emitted from the part 2 to be observed, and the part 2 to be observed is examined by detecting the secondary electron with an electron microscope. In the case where the later re-observation is required, a gas 8 containing metal compound such as tungsten and molybdenum is supplied to the vicinity of the part 2 to be observed, and, via the gas 8, the vicinity of part 2 to be observed is irradiated with a converged ion beam 6, to form a mark 7. On the occasion of re-observation, the part is irradiated with primary ion beam 3, and then a lot of secondary electrons are excited and emitted from the mark 7. By detecting them with a secondary electron microscope, the position of the mark 7 can be easily recognized. Thereby, the part 2 to be observed necessary for re-observation can be easily found out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for observing defects in semiconductor devices, and particularly to a method for performing 111 observations of a location that has been observed once.

[Prior Art] FIG. 3 is a schematic diagram showing the conventional observation knob method for semiconductor devices. In the figure, 1 is a semiconductor device to be observed, 2 is an observed part of the semiconductor device to be observed 1, and 3 is a point to be observed in the semiconductor device to be observed. The primary ion beam irradiated to point 2, 4 is the 2 which is excited and emitted by the primary ion beam 3 being irradiated to the observed semiconductor (+- equipment (?'i 1 of 1☆ observation point 2). The next electron 5 is wiring mounted on the semiconductor device to be observed.

Next, the operation will be explained. When the primary ion beam 3 is irradiated onto the observation point 2 of the conductor device 1, secondary electrons 4 are excited and emitted from the observation point 2. This secondary electron 4
The state of the observation point 2 is known by observing it using a detector such as an electron microscope. Later, the observed point 2
If it is determined that it is necessary to re-observe the area, count the number of interconnects 5 mounted on the semiconductor device 1 to be observed from the end in both the vertical and horizontal directions and record the location of the area to be observed 2. When re-observation is actually carried out, the number of wiring lines 5 is counted from the end in both the vertical and horizontal directions based on the records, thereby finding the observation point 2 and observing it in the same manner as described above.

[Problems to be Solved by the Invention] Since the conventional semiconductor device observation method is as described above, when it is determined that re-observation is necessary, the length and width of the semiconductor device 1 to be observed are The number of wires 5 in the direction is counted and recorded from the end, and when re-observation, the number of wires 5 in the vertical and horizontal directions is counted again to search for the observed location 2. It was a labor-intensive task.

This invention was made to solve the above-mentioned conventional problems, and provides a method for accurately and easily locating re-observation points without requiring the work of counting the wiring on a semiconductor device to be observed. The purpose is to

[Means for Solving the Problems] A method for observing defects in a semiconductor device according to the present invention supplies a gas containing a metal compound to the vicinity of a portion to be observed of a semiconductor device to be observed, and outputs energy through the gas. By irradiating the adjusted focused ion beam toward the vicinity of the observed part of the semiconductor device to be observed and creating a metal mark there, the primary ion beam was irradiated to the semiconductor device to be observed in direction i). At this time, a large amount of secondary electrons are excited and emitted from the landmark,
By detecting this, the position in the vicinity of the observation point is recognized, and then a primary ion beam is directed at the observation point, and the secondary electrons excited and emitted from it are detected. .

[Operation] The semiconductor device defect observation method according to the present invention irradiates a focused ion beam through a gas containing a metal compound toward the vicinity of the observation point of the semiconductor device to identify the metal mark. When the primary ion beam is irradiated towards the i14 conductor device to be observed, a large amount of secondary electrons are excited and emitted from the metal mark, and by detecting this, it is easy to locate the point to be observed. can be searched for.

[Embodiments of the invention] The embodiments of this invention will now be described with reference to the drawings.

FIG. 1(a), FIG. 1(b), and FIG. 1(c) are schematic diagrams showing embodiments of the present invention, and 1.2.3.
4 is the same as the conventional one shown in FIG. 3, and its explanation will be omitted. In Figure 1 (one), 6 is the Kato ion beam, 7 is the J mark, 8 is gas, and 9 is a large amount of 2
It is the next electron.

Next, the operation will be explained. In FIG. 1(a), when a primary ion beam 3 is irradiated onto an observed location 2 of a conductive device 1 to be observed, secondary electrons 4 are excited and emitted from the observed location 2. By detecting using a detector such as an electron microscope, the observation point 2 of the semiconductor device 1 to be observed is observed. When observation is necessary, in FIG. 1(b), a gas 8 containing a metal compound such as tungsten or molybdenum is supplied around the observation point 2, and focused ions are beam 6
A mark 7 is created by irradiating the vicinity of the observation point 2. When performing re-observation, as shown in FIG. 1(c), when the semiconductor device 1 to be observed is irradiated with the primary ion beam 3, a large amount of secondary electrons 9 are excited and emitted from the mark 7. By detecting it with a detector such as a secondary electron microscope, the position of the landmark 7 can be easily detected, and therefore the observation point 2 that requires re-observation can be easily searched for.
can be done. The observation method after this is shown in Section 11 (a).
This method is omitted because it is the same as the brightest method in .

In the example of LHa, although the case of double wiring has been described, if the semiconductor device to be observed 11t1 is covered with the insulating film 10 as shown in FIG.
After creating an opening 11 in the insulating film 10 by increasing the energy of
Create above. At the time of re-observation, even if the insulating film 10 is removed, the mark 7 remains on the semiconductor device 1 to be observed, so the point to be observed 2 can be found and observed using the same method as described above.

Further, in the above example, there is one mark 7, but the number is arbitrary.

[Effects of the Invention] As described below, according to the present invention, by irradiating a focused ion beam toward the vicinity of an observed part of a semiconductor device to be observed through a gas containing a metal compound, When a metal mark is created and a primary ion beam is irradiated towards the semiconductor device to be observed, a large number of secondary electrons are excited and emitted from the mark, and by detecting this, the position of the part to be observed can be determined. It is possible to search for defects accurately and easily, thus improving work efficiency in observing defects in conductor devices.

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (C) and FIG. 2 are schematic diagrams showing an embodiment of the present invention, and FIG. 3 is a schematic diagram showing a conventional method. In the figure, 1 is a semiconductor device to be observed, 2 is a part to be observed,
3 is a primary ion beam, 4 is a secondary electron, 5 is a wiring, 6 is a focused ion beam, 7 is a "l" mark, 8 is a gas, 9 is a multi-component secondary electron, 10 is an insulating film, 11 is an opening It is. Note that the same reference numerals in the drawings indicate the same or +11 portions.

Claims (3)

[Claims] (1) A gas containing a metal compound is supplied to the vicinity of the observation point of the semiconductor device to be observed, and a focused ion beam with adjusted output energy is directed toward the vicinity of the observation point of the semiconductor device to be observed. A mark made of the metal is created by irradiation through a gas, and a primary ion beam is irradiated toward the semiconductor device to be observed. detecting secondary electrons, determining a position near the observation point of the semiconductor device to be observed, and irradiating the observation point of the semiconductor device to be observed with a primary ion beam; A method for observing defects in a semiconductor device, comprising detecting secondary electrons excited and emitted from a location to be observed by irradiation with the primary ion beam. (2) By irradiating the focused ion beam toward the vicinity of the observation point of the semiconductor device to be observed covered with an insulating film, the insulating film is opened and a mark is created in the vicinity of the observation point. A method for observing defects in a semiconductor device according to claim 1, characterized in that: (3) The method for observing defects in a semiconductor device according to claim 1 or 2, wherein the metal compound is a compound of tungsten or molybdenum.