JP2939503B2 - Sample holding method in X-ray diffraction test etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample holding method for an X-ray diffraction test and a flatness measurement test. In particular, X
Of single crystal wafers and epitaxial films using X-ray diffractometer (rocking curve in-plane mapping measurement [crystal integrity, compound semiconductor composition ratio, lattice distortion of surface layer,
Superlattice structure], lattice constant, total reflection X-ray analysis, asymmetric reflection X-ray analysis, etc.) and flatness measurement of a thin plate using a flatness measuring machine.

[0002]

2. Description of the Related Art Conventionally, as a sample holding method in an X-ray diffraction test and a flatness measurement test, a mechanical chucking method is mainly employed. Further, a method of fixing the entire sample using the surface tension of ethanol on the sample stage, or a method of evenly applying a thin layer of silicone grease to the entire sample stage and fixing the sample is also adopted.

[0003]

However, in the method of mechanical chucking, since a fixing claw or the like pushes the sample from the outer peripheral direction toward the center, literally, stress is applied to the sample and high measurement accuracy is obtained. Is difficult to obtain. The method using ethanol is fixed by its surface tension. However, when a portion where there is no ethanol is generated due to volatilization of ethanol between the sample and the sample stage, a stress is applied to the portion. Further, when the thickness of ethanol is reduced as a whole, stress is applied to the sample due to unevenness of the sample stage, unevenness of the sample, and dust caught between the sample and the sample stage. Further, in the method using silicone grease, the adsorbing force is applied to the sample, stress at the time of bonding caused by unevenness of the amount of the adhesive easily remains, and the sample is easily distorted. As a result, it was found that even with these methods, highly accurate measurement was difficult.

[0004]

According to the present invention, there is provided a method for vertically holding a flat sample in an X-ray diffraction test or a flatness measurement test, wherein a part near the upper center of the sample is held by a sample holder. Is vertically suspended. In addition, the holding method is provided with an adhesive member between a part near the upper center of the sample and the sample holder, the adhesive member is a double-sided adhesive tape, and the holding method is the upper center of the sample. Vacuum chuck a part of the vicinity
It is an preferred embodiment and.

[0005]

According to the present invention, by holding a part near the upper center of the sample and the holder, a stress for holding the sample is not applied, and the weight of the sample is not added, so that highly accurate measurement is possible. Becomes The workability is good if the holding method uses an adhesive member provided between a part near the upper center of the sample and the sample holder, for example, a double-sided adhesive tape. Also, if a jig is manufactured so that a part of the sample near the center upper portion can be vacuum chucked, the workability is also good.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, an in-plane rocking curve mapping measurement using an X-ray diffraction apparatus will be described below. (Example 1) Si wafer considered to have the highest crystallinity at present (made by Shin-Etsu Semiconductor, 4 inches, thickness: 0.5 mm, (001)
Surface cut) was used. The measurement conditions are shown below. Incident side monochromator: Ge (440) 4 crystal, tube: Cu, tube voltage: 40 KV, tube current: 30 mA, beam diameter: 1 × 3
mm, scanning method: ω scan, step width: 0.000
25 °, measurement time: 1.85 seconds, scan width: 0.08
°. FIG. 1 shows the measurement points (25 locations) of the wafer. The sample holding method is 5mm x 5mm
The double-sided adhesive tape is applied, and only the back and top of the wafer are adhered and fixed. Two measurements were made to confirm the reproducibility of the results. Table 1 shows the results. In both cases, the half widths of the rocking curves at all the measurement points were 5 seconds. In addition, there was reproducibility of Omega, and the variation was 0.16 seconds. Further, the variation of Psi was 3.16 seconds. Here, OMEGA is
The measurement plane angle parallel to the X-ray incidence direction, psi,
The measurement plane angle is perpendicular to the X-ray incidence direction. Also,
The variation indicates the difference between the maximum value and the minimum value of each of the measured relative omega and relative psi. The relative omega is a value obtained by subtracting the average value of omega measured at 25 points from omega at each measurement point. The relative psi is obtained by subtracting the average value of psi measured at 25 points from the psi at each measurement point. Note that FWHM in the table indicates the half width of the rocking curve. As described above, the embodiment of the mapping measurement in the rocking curve using the X-ray diffraction apparatus is used, but the present invention is not limited to this. Obviously, a measuring instrument that does not preferably apply stress to the measurement sample may be used.

Comparative Example 1 A sample was fixed with a mechanical chuck. Others were the same as Example 1. Table 2 shows the results. The half width of the rocking curve varies from 5 to 10 seconds, and the reproducibility is poor. The reproducibility of OMEGA was also poor, and the variation was 3.71 seconds. Furthermore, the variation of the psy was 30.42 seconds.

Comparative Example 2 A few drops of ethanol were dropped on a sample stage and fixed using the surface tension.
Others were the same as Example 1. Table 3 shows the results. The half width of the rocking curve varies from 5 to 16 seconds, and the reproducibility is poor. The reproducibility of OMEGA was also poor, and the variation was 3.05 seconds. further,
The variation of Psai was 40.26 seconds.

Comparative Example 3 Silicone grease was evenly and thinly applied on the entire sample stage to fix the wafer. Others were the same as Example 1. Table 3 shows the results.
Shown in The half width of the rocking curve varies from 5 to 16 seconds, and the reproducibility is poor. The reproducibility of OMEGA was also poor, and the variation was 4.71 seconds. In addition, the variation in Psi was 44.09 seconds.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

According to the present invention, by supporting a part of the sample near the center upper portion on the sample holder and hanging the sample vertically,
The present invention provides crystallinity analysis of single crystals and epitaxial films,
In turn, it will make a huge contribution to the development of science and industry.

[Brief description of the drawings]

FIG. 1 Measurement point position in the Si wafer surface and double-sided adhesive tape adhesion position

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 23/00-23/227 G01N 1/28 G21K 7/00

Claims (4)

(57) [Claims] 1. A method for vertically holding a flat sample in an X-ray diffraction test or a flatness measurement test, wherein a portion near the upper center of the sample is held in a sample holder and the sample is vertically hung down. A sample holding method in an X-ray diffraction test or the like. 2. The sample holding method in an X-ray diffraction test or the like according to claim 1, wherein said holding method includes providing an adhesive member between a part near a central upper portion of the sample and the sample holder. 3. The method for holding a sample in an X-ray diffraction test or the like according to claim 2, wherein the adhesive member is a double-sided adhesive tape. 4. The method for holding a sample in an X-ray diffraction test or the like according to claim 1, wherein said holding method vacuum-chucks a portion near the upper center of the sample.