JPH05135724A - Sample holder for electron microscope - Google Patents

Abstract

PURPOSE:To provide a sample holder for an electron microscope not requiring to cut a sample or deposit a conducting film such as gold in the electron microwave observation of a wafer or a photo-mask having a structure easy to charge up. CONSTITUTION:A wafer 6 mounted on a holder main body 7 is fixed with a wafer presser 11 and a fixing pin 9. The wafer presser 11 is firmly pressed to the surface of the wafer 6 by a spring 10' to assure the contact between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron microscope used for observing and analyzing semiconductor devices or photomasks.

[0002]

2. Description of the Related Art A conventional sample holder for an electron microscope is shown in FIGS. 2 (a) and 2 (b).

FIG. 2B is a sectional view of a conventional sample holder for an electron microscope.

A wafer 6, which is a substrate of a semiconductor device, is placed horizontally on a holder body 7 of an electron microscope and sandwiched between a fixing pin 9 and a wafer retainer 8. The wafer retainer 8 can firmly fix the wafer 6 by pressing the wafer 6 against the fixing pin 9 by the spring 10.

An electron microscope irradiates a finely focused electron beam while scanning it over a certain range of a sample, and detects secondary electrons emitted from the sample when the electron hits them, thereby increasing the intensity of the secondary electrons. The signal thus detected is imaged.

When the sample is insulated when irradiated with the electron beam, charges accumulate in the part irradiated with the electron beam, the charge is detected as a background noise component by the detector, and the image turns black. It will be very difficult to see. This is called charge-up.

Therefore, the wafer 6 is grounded from the bottom surface of the wafer 6 via the holder main body 7, the stage of the electron microscope, etc., and the charges are released to obtain a clean image.

However, as shown in the principle of the prior art sample holder for an electron microscope of FIG. 2A, when silicon 1 which is a raw material of a wafer is covered with an insulating film 2 such as a silicon oxide film, it is insulated. The conductive film 3 made of aluminum or the like on the film 2 becomes electrically floating and is charged up,
Observation of the resist pattern 4 became very difficult.

[0009]

However, in the electron microscope sample holder of the prior art, electrical grounding cannot be sufficiently performed when observing without cutting the substrate or the photomask of the semiconductor device, and thus a clear image observation is possible. It had a problem that it could not be done.

Therefore, the present invention is intended to solve such a problem, and an object thereof is to provide a sample for an electron microscope capable of observing a clean image even when observing without cutting a substrate or a photomask of a semiconductor device. It is in the place of providing a holder.

[0011]

In order to solve the above problems, the sample holder for an electron microscope of the present invention is an electron microscope sample holder for mounting a substrate or a photomask of a semiconductor device without cutting the semiconductor device. Provide a terminal that comes into contact with the substrate of or the front surface of the photomask,
The terminal is electrically grounded.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG.
An explanation will be given based on (b).

FIG. 1A shows the principle of the sample holder for an electron microscope of the present invention.

The surface of silicon 1 which is the raw material of the wafer is covered with an insulating film 2 such as a silicon oxide film, and a conductive film 3 such as aluminum is sputtered on the insulating film 2. Furthermore, the resist pattern 4 formed on the conductive film 3 is to be observed with an electron microscope.

The principle of the sample holder for an electron microscope of the present invention is that, in addition to the ground 5 of the sample holder for an electron microscope of the prior art, the ground 5'from the front surface of the wafer is the conductive film 3 '.
In the case of cutting the sample which is to release the electric charge accumulated in the conductive film 3 on the insulating film 2 and observe it with an electron microscope, a conductive film such as gold or platinum is vapor-deposited on the surface of the cut sample. By sputtering, a clean image can be observed even on a sample that is easily charged up, but when observing a wafer, which is a substrate of a semiconductor device, with an electron microscope in the middle of the manufacturing process, The wafer cannot be cut. Also, since the wafer has to be returned to the manufacturing process again, it is not possible to deposit a conductive film such as gold.

Therefore, by using the sample holder for an electron microscope of the present invention, the conductive film on the insulating film can be observed without cutting the wafer and vapor deposition of gold or the like. It becomes possible to perform electron microscope observation in the middle of the manufacturing process.

FIG. 1 (b) is a sectional view of the sample holder for an electron microscope of the present invention.

The wafer 6, which is the substrate of the semiconductor device, is placed horizontally on the holder body 7 of the electron microscope, and is sandwiched between the fixing pin 9 and the wafer retainer 11.

The wafer retainer 11 can press the wafer 6 in the horizontal direction by the spring 10 and fix it to the fixing pin 9. At the same time, the wafer retainer 11 is also in contact with the front surface of the wafer 6, and the spring 10 'firmly presses the wafer retainer 11 against the front surface of the wafer 6 so that the contact between the two is ensured. It has a simple structure.

As a result, the wafer 6 is connected to the ground 5 from the bottom surface of the wafer 6 and the front surface of the wafer 6 via the holder body 7, the stage of the electron microscope and the like.

Further, in the embodiment of the present invention, the wafer which is the substrate of the semiconductor device is taken as the sample to be observed, but the same effect can be obtained by applying it to the substrate of the photomask or the liquid crystal display.

[0022]

As described above, the sample holder for an electron microscope of the present invention is provided with a terminal which comes into contact with the front surface of the substrate of the semiconductor device or the photomask, and the terminal is electrically grounded. Due to the simple structure, even a sample having a structure that easily charges up can be observed clearly without cutting the sample.

Along with this, there is also an effect that the work efficiency of sample analysis and the like is improved. Further, since the charge up to the sample can be suppressed, there is an effect that even a worker who is not accustomed to focus adjustment can observe a clear image.

[Brief description of drawings]

1A is a principle view of a sample holder for an electron microscope of the present invention, and FIG. 1B is a sectional view of a sample holder for an electron microscope of the present invention.

2A is a principle view of a conventional sample holder for an electron microscope, and FIG. 2B is a sectional view of a conventional sample holder for an electron microscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon 2 Insulating film 3 Conductive film 4 Resist pattern 5 Earth 5'Earth from front side of wafer 6 Wafer 7 Holder body 8 Wafer holder 9 Fixing pin 10 Spring 10 'Spring 11 Wafer holder

Claims (1)

[Claims] 1. A sample holder for an electron microscope on which a substrate of a semiconductor device or a photomask is placed without being cut, and a terminal is provided which is in contact with the front surface of the substrate of the semiconductor device or the photomask. A sample holder for an electron microscope, which is electrically grounded.