JPH04330751A - Potential evaluating method and device - Google Patents

Abstract

PURPOSE:To evaluate the potentials easily and rapidly without restraining the environment of a specimen or properties of the specimen itself, etc., at all. CONSTITUTION:The laser polarized light 1a radiated from a light source 1 is directed to a specimen 2 for scanning through the intermediary of multiple mirrors 3 and 4 swingable in synchronism so that the level of rotation angle in the polarized light direction to the laser polarized light 1a of the reflecting light 1b reflecting the potential level at the irradiated part of the specimen 2 may be detected to be outputted to a display 6 as values or images.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to potential evaluation technology.
In particular, it relates to techniques that are effective when applied to non-contact potential evaluation of various samples such as semiconductor devices and living organisms.

0002

[Prior Art] For example, in the field of manufacturing semiconductor devices,
For test research, product failure analysis, and other purposes, it may be necessary to non-contactly evaluate changes and magnitudes of potential at specific parts of semiconductor integrated circuits, as well as the overall potential distribution. Conventionally, as a technique for evaluating the potential distribution of a sample, for example, "LSI Handbook" published by Ohmsha Co., Ltd., November 30, 1980, edited by the Institute of Electronics and Communication Engineers, P.
As described in documents such as 665-P666,
EB test equipment is known. In other words, by utilizing the fact that the amount of secondary electrons generated when a sample is irradiated with an electron beam reflects the magnitude of the potential at the part irradiated with the electron beam, the potential at a desired part of the sample such as a semiconductor integrated circuit can be determined. This is a precise evaluation of the

0003

However, since the conventional EB test apparatus described above uses an electron beam, it is necessary to place the sample to be measured in a vacuum. For this reason, it is not possible to evaluate the potential of samples under actual conditions of use, such as in the atmosphere, or of biological samples. There is a problem in that a jig or the like must be prepared for each sample to bring the sample into operation. Also,
Complicated work such as loading and unloading samples into and out of the vacuum chamber is also required.

[0004] Accordingly, an object of the present invention is to provide a potential evaluation method that enables simple and quick potential evaluation without imposing restrictions on the environment in which the sample is placed or the properties of the sample itself. be.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0006]

[Means for Solving the Problems] Among the inventions disclosed in this application, a brief overview of typical inventions will be as follows.
It is as follows.

That is, the potential evaluation method according to the present invention is as follows:
This method measures the change in the polarization direction of reflected light obtained by irradiating a sample with laser polarized light, and non-contactly evaluates the magnitude of the potential on the sample surface.

Further, the potential evaluation method according to the present invention is to two-dimensionally evaluate the magnitude of the potential on the sample surface by scanning the sample surface with laser polarized light.

Further, the potential evaluation device according to the present invention includes a light source that emits laser polarized light, a scanning means that scans a desired sample with the laser polarized light, and a scanning device that scans the reflected light generated by irradiating the sample with the laser polarized light. It is equipped with a photodetection means for measuring a change in the polarization direction with respect to laser polarized light, and an output means for converting the magnitude of the change in the polarization direction into the magnitude of the electric potential at the sample and outputting it.

Further, in the potential evaluation device according to the present invention, the scanning means is constituted by a plurality of swinging mirrors whose reflecting surfaces have different rotation axes, and the laser beam reflected by each swinging mirror swings in synchronization. By superimposing changes in the optical path of polarized light, the sample is scanned with laser polarized light.

Further, the potential evaluation apparatus according to the present invention includes a scanning means, a rotation stage that supports at least one sample, and a linear movement means that linearly moves the light source and the light detection means relatively in the radial direction of the rotation stage. By combining the rotation of the sample by the rotary stage and the linear movement of the light source and the light detection means, scanning of the sample with laser polarized light is performed.

0012

[Function] According to the potential evaluation method of the present invention described above, the change in the polarization direction of the reflected light of the laser polarized light irradiated to an arbitrary part of the sample is measured to evaluate the potential at the irradiated part. There is no need to place it in a special environment with many restrictions, such as in a vacuum.

[0013] Therefore, it is possible to evaluate the potential of a sample under actual usage conditions such as in the atmosphere, and it is also possible to evaluate the potential of not only inorganic samples such as semiconductor devices but also biological samples. , there is no need to prepare special measurement jigs. As a result, potential evaluation can be performed simply and quickly without any restrictions on the environment in which the sample is placed or the properties of the sample itself.

Further, according to the potential evaluation device of the present invention, the change in the polarization direction of the reflected light of the laser polarized light that is irradiated or scanned on any part of the sample is measured, and the potential at the irradiated part is evaluated. Therefore, there is no need to place the sample in a special environment with many restrictions such as in a vacuum, and potential evaluation can be performed on the sample under actual usage conditions such as in the atmosphere. It is also possible to evaluate the potential of biological samples, etc., and there is no need to prepare special measurement jigs. As a result, potential evaluation can be performed simply and quickly without any restrictions on the environment in which the sample is placed or the sample itself.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A potential evaluation method and apparatus which are an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic perspective view schematically showing an example of the configuration of a potential evaluation device according to an embodiment of the present invention, and FIG.
FIG. 2 is a schematic perspective view schematically showing the principle of potential evaluation.

As shown in FIG. 1, the potential evaluation device of this embodiment includes a light source 1 that emits laser polarized light 1a, and a laser polarized light 1a emitted from this light source 1, for example, to a semiconductor integrated circuit or a biological sample. A plurality of swinging mirrors 3 and a swinging mirror 4 are provided to guide the sample 2 to the sample 2. Swinging mirror 3
and 4 are arranged with their respective swing axes 3a and 4a intersecting each other, and are operated by drive motors 3b and 4b that operate in synchronization with each other according to instructions from a control computer (not shown) or the like. , a desired swing angle with respect to the laser polarized light 1a is realized, and scanning of the laser polarized light 1a with respect to the sample 2 is realized. That is, the swinging mirror 3 is configured to rotate the laser polarized light 1 emitted from the light source 1.
It is placed on the optical path of a, with the swing axis 3a being substantially perpendicular to the plane of the sample 2, for example, and serves to change the irradiation position of the laser polarized light 1a in the X direction in FIG. Further, the swinging mirror 4 is located on the optical path of the laser polarized light 1a reflected by the swinging mirror 3, and is arranged with the swing axis 4a substantially parallel to the plane of the sample 2, and the laser polarized light is directed in the Y direction. This is to change the irradiation position of 1a. and,
By changing the swing angles of both in synchronization,
Changes in the reflection angles of the laser polarized light 1a on each of the swing mirrors 3 and 4 are superimposed, and the sample 2 is scanned with the laser polarized light 1a.

Further, the reflected light 1b generated from the irradiated part of the sample 2 with the laser polarized light 1a follows a path almost opposite to that of the laser polarized light 1a, and enters the photodetector 5 disposed near the light source 1. is configured to do so. This photodetector 5 functions to convert the magnitude of the polarization direction of the reflected light 1b with respect to the laser polarized light 1a irradiated onto the sample 2 into the magnitude of a predetermined electric signal, and the obtained electric signal is Furthermore, after a predetermined calculation process is performed through a calculation device (not shown), etc., specific numerical values or color or black and white multi-level information may be displayed on the screen of a display device 6 such as a CRT device as necessary. It is output as image information, etc.

It should be noted that each of the above-mentioned components may be installed in a normal clean atmosphere, and there is no need to provide a special closed room or the like. Further, the sample 2 may be placed at a predetermined location as it is in actual use, if necessary. Furthermore, the potential evaluation device may be transported and installed at the place where the sample 2 is normally operated, if necessary.

Note that in the configuration of the potential evaluation device described above, for convenience, the light source 1 for the laser polarized light 1a and the photodetector 5 for capturing the reflected light 1b are separately provided, but the present invention is not limited to this, and for example, It goes without saying that, like an optical head used in an optical disk device, the two may be integrally constructed by appropriately using an optical element such as a polarizing beam splitter.

An example of the operation of the potential evaluation device of this embodiment will be explained below.

When the laser polarized light 1a is emitted from the light source 1 while changing the swing angles of the individual swing mirrors 3 and 4 synchronously, the laser polarized light 1a scans a desired part of the sample 2 and Reflected light 1b generated from the irradiation site of the laser polarized light 1a enters the photodetector 5 following a substantially opposite path. Here, as shown in FIG. 2, the polarization direction of the reflected light 1b is changed by Δθ depending on the magnitude of the potential at the generation site of the reflected light 1b in the sample 2.
rotates with respect to the polarization direction. And the photodetector 5 is
The amount of rotation Δθ in the polarization direction is converted into a predetermined electrical signal and output to the display device 6 side. Further, in an arithmetic device (not shown) interposed between the photodetector 5 and the display device 6, the amount of rotation Δθ of the polarization direction is converted into a signal reflecting the magnitude of the potential, and the signal is output to the display device 6. Note that, as the conversion process, for example, the coordinate values of each part of the sample 2 and the magnitude of the electric potential detected at the coordinate values may be correlated and output as numerical information, or the electric potential in the sample 2 may be output as numerical information. It may also be output as a colored image or a bright/dark image that reflects the distribution of the image.

As described above, according to the potential evaluation apparatus of this embodiment, complicated considerations such as installing the sample 2 in a special environment such as a vacuum chamber or preparing a special test jig are not required. It is possible to evaluate the potential of the sample 2 in a desired state quickly, simply, and with high precision without having to do so. Further, the sample 2 is not limited to an inorganic object such as a semiconductor device, but may be an organic object such as a living body.

Next, an example of a potential evaluation device according to another embodiment of the present invention will be explained with reference to FIG.

The potential evaluation apparatus shown in FIG. 3 is driven by a motor 10 and includes a rotary table 11 on which a plurality of samples 2 are placed at predetermined positions. This rotary table 1
A light source 1 that emits laser polarized light 1a downward and a photodetector 5 that detects reflected light 1b are provided above the rotary table 11 by a motor 12.
It is supported by a moving mechanism 13 that moves linearly in the radial direction.

By combining the rotational displacement of the sample 2 due to the rotation of the rotary table 11 and the linear displacement of the light source 1 and the photodetector 5, which move across the direction of rotation, the laser polarized light 1a relative to the sample 2 is adjusted. It performs scanning. Also, a motor 1 that drives the rotary table 11
Based on the rotational position of the rotary table 11 obtained from 0, it is possible to identify which of the plurality of samples 2 on the rotary table 11 the reflected light 1b comes from, so that the potential evaluation work of the plurality of samples 2 can be performed simultaneously. can do.

That is, according to the potential evaluation apparatus of the embodiment shown in FIG. 3, the same effects as the above-described potential evaluation apparatus of FIG. As a result, productivity in potential evaluation work can be significantly improved.

[0028] Although the invention made by the present inventor has been specifically explained based on examples, the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Needless to say.

[0029]

[Effects of the Invention] According to the potential evaluation method of the present invention, potential evaluation can be easily and quickly performed without any restrictions on the environment in which the sample is placed or the properties of the sample itself. .

Further, according to the potential evaluation device of the present invention, potential evaluation can be easily and quickly performed without any restrictions on the environment in which the sample is placed or the properties of the sample itself. .

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view schematically showing an example of the configuration of a potential evaluation device that is an embodiment of the present invention.

FIG. 2 is a schematic perspective view schematically showing the principle of the potential evaluation technique of the present invention.

FIG. 3 is a schematic perspective view schematically showing an example of the configuration of a potential evaluation device according to another embodiment of the present invention.

[Explanation of symbols] 1. Light source 1a Laser polarization 1b Reflected light 2 Sample 3 Swinging mirror 3a Swing axis 3b Drive motor 4 Swinging mirror 4a Swing axis 4b Drive motor 5 Photodetector 6 Display device 10 Motor 11 Rotating table 12 Motor 13. Moving mechanism

Claims (5)

[Claims] 1. A potential evaluation method, which comprises irradiating a sample with laser polarized light and measuring changes in the polarization direction of reflected light to non-contactly evaluate the magnitude of the potential on the sample surface. 2. The potential evaluation method according to claim 1, wherein the magnitude of the potential on the sample surface is two-dimensionally evaluated by scanning the sample surface with the laser polarized light. 3. A light source that emits laser polarized light, a scanning device that scans a desired sample with the laser polarized light, and a scanning means that scans the laser polarized light with respect to the polarization direction of the reflected light generated by irradiating the sample with the laser polarized light. 1. A potential evaluation device comprising: a photodetection device for measuring a change; and an output device for converting the magnitude of the change in the polarization direction into a magnitude of a potential in the sample and outputting the result. 4. The scanning means is comprised of a plurality of swinging mirrors with reflecting surfaces having different rotation axes, and superimposes changes in the optical path of the laser polarized light reflected by each of the swinging mirrors that swing synchronously. 4. The potential evaluation apparatus according to claim 3, wherein scanning of the laser polarized light with respect to the sample is realized by causing the sample to be scanned. 5. The scanning means includes a rotation stage that supports at least one of the samples, and a linear movement means that linearly moves the light source and the light detection means relatively in a radial direction of the rotation stage, 4. The potential evaluation device according to claim 3, wherein scanning of the laser polarized light with respect to the sample is realized by combining rotation of the sample by a rotation stage and linear movement of the light source and light detection means. .