JPS58112341A - Analyzing unit for integrated circuit - Google Patents

Abstract

PURPOSE:To obtain an IC analyzing unit not affecting elements in an IC other than the one to be subjected to analysis by a method wherein an optical microscope is employed to visually pre-determine a spot to be analyzed in the IC and the miscroscope is positioned in parallel with an electron beam unit covering only the element to be measured for voltage and the like. CONSTITUTION:An electron beam unit has an electron detector 16 resembling a micro-channel plate on top of a specimen 10. Voltages and so forth detected by the electron detector 16 go through a signal processing circuit 17 to be exhibited on a display unit 18 composed for example of a CRT. Operation of an operational mode selector circuit 20 supplies a corresponding controlling signal to a blanking electrode 4 via a beam-erasing circuit 19 for the erasure of electron beams. Deflecting voltages out of a deflecting system controlling circuit 21 are supplied to an X-axis deflector electrode 7 and Y-axis deflecting electrode 8, fixing the angle of deflection theta in turn defining on the specimen 10 a scope of vision L. In addition, an optical microscope 22 is provided. Mounted on a stage 25 located under the optical microscope 22 is a specimen 24, similar in property to the specimen 10 under the electron beam unit. The specimen 24 is oriented on the stage 25 as the specimen 10 is on the stage 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an integrated circuit analysis device, and in particular to a movement of an electron beam stage and an electron lens for irradiating a sample with an electron beam to analyze voltages inside the integrated circuit. Regarding an integrated circuit analysis device in which the magnification switching of the system is linked with the movement of the stage of a separate optical microscope and the magnification switching mechanism of the optical lens system (2) Background of technology Recently, voltages etc. inside integrated circuits have been measured. As an apparatus for analyzing integrated circuits, a predetermined measurement position is selected by irradiating an integrated circuit sample placed on a stage and scanning the sample from end to end in a frame. After selecting a predetermined measurement position, the voltage and the like at the measurement position are measured to analyze the sample.

In this case, a large amount of electron beam is irradiated even at the measurement location where there is no need for a stand to irradiate the electron beam, causing characteristic changes in other elements of the integrated circuit, resulting in damage to areas other than the measurement part due to electron beam irradiation. There was a demand for an integrated circuit analysis device that does not give

(3) Prior art and problems Figure 1 is a route map showing a conventional integrated circuit analysis device using an electron beam.
The electron beam 3 emitted from the blanking electrode 4.
The light is focused and directed into a predetermined shape through the aperture 6 of the condenser lens 5.

Further, the electron beam 3 is connected to an X-axis deflection electrode 7 for scanning deflection and a Y-axis deflection electrode 7 for scanning deflection.
Scanning and deflection control is performed in the X-axis and Y-axis directions via the axial deflection electrode 8 , and irradiation is projected onto the sample 10 via the objective lens 9 .

The sample IO is stage 1 that moves in the X-axis or Y-axis direction.
1, and is configured to be continuously moved in one predetermined direction by a stage moving device 12 consisting of a servo motor, a moving drive means, etc.

In the above configuration, if measurement is to be performed at point 14 on the sample 10, for example, the electron beam 3 is moved onto the sample by the cooperation of the stage moving device and the control signals applied to the X-axis and Y-axis deflection electrodes for scanning deflection. The integrated circuit sample 10 is analyzed by frame scanning 13, detecting a point 14, and performing voltage measurements and the like.

For this reason, there is a risk that thermal energy of the electron beam 3 will be applied to many elements in the middle of frame scanning 13, causing characteristic changes.

(4) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides an optical microscope to visually determine the location of the analysis location in parallel in order to select and display the analysis location of the integrated circuit. The object of the present invention is to obtain an integrated circuit analysis device that does not damage other elements in the integrated circuit by irradiating electron beams to only certain locations and measuring voltage, etc.

(5) Structure of the Invention This object is the structure of the present invention, in an integrated circuit device that analyzes the operation of an integrated circuit by measuring voltages inside the integrated circuit using an electron beam. Optical I moves the stage on which the sample to be irradiated with the electron beam is placed and changes the magnification of the electron lens system for the electron beam.
i! This is achieved by providing an integrated circuit analysis device characterized in that it is linked with the movement of a microscopic stage and the switching of the magnification of an optical lens system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing the schematic configuration of the integrated circuit analysis apparatus of the present invention, and the same parts as in FIG. 1 are given the same reference numerals and redundant explanation will be omitted.

The electron beam device has an electron detector 16 such as a microchannel plate above the sample 10.
The measured voltages and the like detected from 6 are displayed on a display device 18 such as a cathode ray tube through a signal processing circuit 17.

Furthermore, a beam erasing circuit 1 is connected to the blanking electrode 4 according to the switching state given by the operation mode switching circuit 20.
A control signal is applied through 9 to perform electron beam erasure and the like.

Further, a deflection voltage from a deflection system control circuit 21 is applied to the X-axis and Y-axis deflection electrodes 7.8, and the deflection angle θ is determined by the deflection voltage, thereby determining the viewing range on the sample 10.

In the present invention, in addition to the electron beam device as described above, an optical microscope 22 is provided, and a stage 2 is provided at the lower end of the optical microscope.
A sample 24 of the same type as the measurement sample 10 of the electron beam apparatus is placed on the stage 5 at the same position and in the same direction as the stage 11. Stages 11 and 25 are configured to be moved in the X-axis and Y-axis directions by stage moving devices 12.26, respectively.

The servo pulse motors and the like of the stage moving devices 12 and 26 are each driven and controlled by motor drive circuits 27 and 28, and the motor drive circuits 27 and 28 are driven in synchronization by a stage movement control circuit 29 in the gongbuter. Therefore, the stage 11 for the electron beam device and the stage 25 for the optical microscope
move in sync with.

Further, the optical system of the optical microscope 22 has a plurality of magnification lens systems 23a, 23b, etc. ranging from low magnification to high magnification, and these optical systems pass through the viewing position by rotating the rotary table 23. A magnification lens system 23a is placed on the center line 33 of the optical microscope.
, 23b, this rotation state is detected by a detection means 30 such as a microsinch, and a voltage or current corresponding to the magnification of the magnification lens system is detected by a magnification detection circuit 31.
is generated and applied to the deflection system control circuit 21.

That is, if the magnification of the magnification lens system of the optical microscope 22 is, for example, the viewing angle is 01 and the viewing range on the sample 24 is within the range expressed by Ll, then the field of view L is at the deflection angle θ1θ−θ1 of the electron beam device.
The control voltages applied to the deflection electrodes 7 and 8 may be controlled so that =L I.

In the above embodiment, the output of the magnification detection circuit 31 was directly given to the deflection system control circuit 21, but the control signals from these magnification detection circuits are added to the computer, and the computer generates a deflection control signal that is given to the deflection system control circuit. The X-axis and Y-axis deflection means may be controlled by calculating the amount of deflection along with the reference deflection amount.

In the above configuration, in order to detect the point 14 to be measured on the same type of sample placed on the stage 11.25, the electron beam device operation mode switching circuit must be set to the planking state or the stage must be completely stopped. 11.25, appropriately select the magnification lens system of the optical microscope 22, find the point 14 to be measured within the field of view L+, and turn on the electron beam 3.
move synchronously and are constructed so that the field of view determined by the magnification of the optical microscope and the deflection angle of the electron beam device is equal. Therefore, the point 14 to be measured is directly irradiated with the electron beam 3, and the secondary Integrated circuits can be analyzed by detecting electrons, etc. and displaying them on the display bag 218. (7) Effects of the invention As explained in detail above, according to the integrated circuit analysis device of the present invention, it is possible to analyze a sample. Since the electron beam is not irradiated to select a location, the integrated circuit can be analyzed without causing thermal damage to elements other than the measurement points.

[Brief explanation of drawings]

FIG. 1 is a route map of a conventional integrated circuit analyzer using an electron beam, and FIG. 2 is a route map of an integrated circuit analyzer according to the present invention. 1...electron gun, 3...electron beam, 7.8...-X
Axis and Y-axis deflection electrodes 1, 10.24...sample, 11.
25... Stage, 12.26... Stage moving device, 14... Measurement point, 16... Detector, 18...
Display device, 20... Operation mode switching circuit, 21.
...Deflection system control circuit, 22...Optical microscope, 23...
・Rotating table, 27.28...Pamotor drive circuit, 29...
- Stage movement control circuit, 30... detection means, 31.
...Magnification detection circuit. Patent applicant Fujitsu Limited

Claims (1)

[Claims] In an integrated circuit analysis device that analyzes the operation of an integrated circuit by measuring the voltage inside the integrated circuit with an electron beam, the steps include moving a stage on which a sample to be irradiated with the electron beam is placed in the integrated circuit analysis device, and the electron beam. An integrated circuit analysis device characterized in that the switching of the magnification of the electronic lens system is linked with the movement of the stage of an optical microscope and the switching of the magnification of the optical lens system.