JPH1114563A - X-ray topographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent X-rays from hitting an object other than a sample and to prevent an obtained X-ray diffraction image from being influenced harmfully by a scattering beam or the like in an X-ray topographic apparatus of a system which scans and moves the sample. SOLUTION: An X-ray topographic apparatus is provided with an X-ray source F which radiates X-rays, with a conveyance device 14 by which a sample and an X-ray film are scanned and moved integrally and with a height limitation slit 2 by which the height in a direction at right angles to the scanning and moving direction A of the sample is limited regarding the X-rays which are radiated from the X-ray source F so as to be incident on the sample. The height size H of the height limitation slit 2 is changed so as to correspond to the scanning and moving operation of the sample. When an X-ray irradiation region E is situated in the largest diameter part of the sample, the height size H of the slit becomes largest. When the end part of the sample reaches the X-ray irradiation region E, the height size H of the slit becomes smallest.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating an X-ray which satisfies a diffraction condition with respect to a crystal lattice plane of a sample to the entire surface of the sample. The present invention relates to an X-ray topographic apparatus for detecting by a detection means and observing a crystal lattice state inside a sample based on the detection result.

[0002]

2. Description of the Related Art As the above-mentioned X-ray topographic apparatus, those based on the Berg-Barrett method, the Lang method, and other various methods are conventionally known. For example, in an X-ray topographic apparatus based on the Lang method, as shown in FIG. 4, the height of an X-ray diverging from a point-focus X-ray source F is limited by a height limiting slit 51, and its width is further reduced. Is limited by the width limiting slit 52, and the sample S is irradiated with the thus obtained X-ray beam having a long and thin cross-sectional shape.
At this time, the incident angle of the X-ray is set to an angle θ that satisfies the diffraction condition with respect to the crystal lattice plane inside the sample S. The X-ray diffracted on the crystal lattice plane of the sample S passes through the scattered radiation regulating slit 53 arranged at the subsequent stage of the sample S, and the X-ray film 5
4, the X-ray film 54 is exposed to light to form a diffraction image.

In the above state, the sample S and the X-ray film 54 are integrally moved in parallel with the surface of the sample S by using a sample moving device 56 as shown by an arrow A. As a result, the entire surface of the sample S is scanned while the X-ray beam having a long and thin cross-sectional shape satisfies the diffraction condition.
Is obtained on the X-ray film 54. By observing the X-ray image, the sample S
It is possible to know lattice states such as lattice defects, lattice distortion distribution, and the form of lattice distortion.

[0004]

As can be seen from the Lang system optical system described above, in the X-ray topographic apparatus, as shown in FIG. 5, the cross-sectional dimension of the X-ray diverging from the X-ray source F is increased. Slit limiting slit 51 and width limiting slit 52
Restricted by. In this case, the width dimension of the width limiting slit 52 is determined by factors such as the size of the X-ray source F and the diffraction conditions. And on the other hand, height limiting slit 5
The dimension 1 is determined according to the maximum diameter of the sample S.

However, in the X-ray topographic apparatus, the sample S scans and moves as indicated by the arrow A, so that the X-ray beam formed by the slits 51 and 52 is not shown in FIG.
When the end of the sample S is illuminated in accordance with the scanning movement of the sample S as shown in (1), X-rays hit a structure other than the sample S, for example, the holder 57 or a rotation mechanism, from which diffraction rays, scattered rays, etc. Has occurred, which adversely affects the measurement.

Therefore, conventionally, when the sample S is small, the height limiting slit 51 is replaced with a small one having a small height dimension Lh, or a scattering prevention screen 59 having a round hole 58 corresponding to the size of the sample S is conventionally used. Was arranged between the sample S and the width limiting slit 52 to prevent the generation of scattered radiation and the like. However, these methods have not been able to completely prevent the X-rays from irradiating objects other than the sample S when the sample S scans and moves.

The present invention has been made in view of the above problems, and in an X-ray topographic apparatus of a type for scanning and moving a sample, it is possible to prevent an X-ray from irradiating an object other than the sample. An object is to prevent the obtained diffraction X-ray image from being adversely affected by scattered radiation or the like.

[0008]

In order to achieve the above-mentioned object, an X-ray topographic apparatus according to the present invention comprises an X-ray source for diverging X-rays, a sample and X-ray detecting means which are integrally moved by scanning. An X-ray topographic apparatus having a sample moving means for causing the X-ray to diverge from the X-ray source and entering the sample in a direction perpendicular to the scanning movement direction of the sample. It is characterized in that the height dimension of the height limiting slit is changed corresponding to the scanning movement.

According to this X-ray topographic apparatus,
Even when the sample size at the X-ray irradiation area changes according to the movement of the sample, the X-ray irradiation area itself can be adjusted according to the change in the size. Such a noise element can be prevented from occurring.

[0010] As the desirable embodiments of the above-mentioned X-ray topographic apparatus, several aspects are conceivable as follows. (1) a sample moving amount detecting means for detecting a moving amount of the sample;
An X-ray topographic apparatus including a slit height changing means for changing the height dimension of the height limiting slit, and a control unit for operating the slit height changing means based on output information of the sample movement amount detecting means Can be configured. Also,

(2) The above-mentioned slit height changing means can be configured to include a screw shaft driven and rotated by a motor, and a slit holder which is screw-fitted to the screw shaft and supports the height limiting slit. . Also,

(3) (a) a circular substance is provided as a sample, and (b) the height dimension of the height limiting slit is the largest when X-rays irradiate the diameter portion of the sample, and X-ray irradiation is performed. It is possible to adopt a control mode in which the area becomes smaller as the distance from the diameter part increases. According to this control mode,
This is particularly advantageous when a circular substance such as a semiconductor wafer is to be measured.

[0013]

FIG. 1 shows an embodiment of an X-ray topographic apparatus according to the present invention. The X-ray topographic apparatus shown here is a Lang-type apparatus as shown in FIG.
It has an optical system arrangement based on the law. This X-ray topographic apparatus includes a point-focus X-ray source F, a divergence limiting slit 1, a pair of upper and lower height limiting slits 2, a width limiting slit 3, and a sample holder 4 for supporting the sample S.
And The optical elements disposed downstream of the sample S are the same as those in the apparatus shown in FIG.

Each of the pair of height limiting slits 2
Supported by the slit holders 6
Is screw-fitted to the screw shaft 7. Screw shaft 7 is pulse motor 8
The upper half of the screw shaft 7 is constituted by, for example, a right-hand screw, and the lower half thereof is constituted by a left-hand screw opposite thereto. An input terminal of the pulse motor 8 is connected to an output port of a CPU (Central Processing Unit) 11 constituting the control unit 9.

Various methods can be considered for supporting the sample S by the sample holder 4. In the present embodiment, the sample S is sandwiched between a pair of high-tensile films 12 having a high X-ray transmittance. The sample S is supported. Sample holder 4
Is fixed on a slide table 13, and the slide table 13 is driven by a transport device 14 and reciprocates linearly as indicated by an arrow A. The movement of the slide table 13 in the direction of arrow A corresponds to the scanning movement direction of the sample S and the X-ray film 54 in the direction of arrow A in FIG. The transport device 14 has, for example, a built-in pulse motor therein, and the input terminal of the pulse motor is a CPU.
11 output ports.

The control section 9 includes a CPU 11 and a memory 16. The memory 16 includes various memory areas such as a main program area storing a program corresponding to the procedure of X-ray topographic imaging, a storage area used as a temporary file for various calculations, and the like. In the memory unit 16, data as shown in FIG. 3 is stored in the form of an arithmetic expression or a table. In this data, the horizontal axis indicates the amount of movement D of the sample S in the radial direction, and the vertical axis indicates the amount of displacement δ of the slit dimension of the height limiting slit 2.

The CPU 11 calculates a procedure for X-ray topographic measurement in accordance with a program stored in the memory unit 16, and includes, in the calculation, an amount of movement of the sample S driven and moved by the transport device 14. A calculation for adjusting the height dimension of the height limiting slit 2 correspondingly is also included.

In the present embodiment, a counting device for counting the number of pulses supplied to the pulse motor in the transfer device 14 is used as a sample movement amount detecting means for detecting the movement amount of the sample S. Further, as a slit height changing means for changing the height dimension of the height limiting slit 2, a structure including a screw shaft 7 driven by a pulse motor 8 and a slit holder 6 screwed to the screw shaft 7 is used. In addition, a computer including the CPU 11 and the memory unit 16 is used as a control unit that operates the slit height changing unit based on the output information of the sample movement amount detecting unit.

Since the X-ray topographic apparatus of this embodiment is configured as described above,
The slide table 13 is moved in the direction of arrow A in accordance with a command from U11, whereby the sample S is scanned and moved together with the X-ray film (see reference numeral 54 in FIG. 4) in the direction of arrow A in FIG. At this time, the CPU 11 calculates the slit displacement amount δ from the radial movement amount D of the sample S based on the data shown in FIG. Then, a pulse signal for rotation is supplied to the pulse motor 8 based on the obtained displacement amount δ, whereby the screw shaft 7 rotates by a predetermined angle. By the rotation of the screw shaft 7, the height H of the slit 2 changes so as to be smaller or larger.

More specifically, as shown in FIG. 1, the amount of movement of the sample S when the X-ray irradiation area E coincides with the maximum diameter portion of the sample S is set to D = 150 mm. As described above, the moving amount at one end position of the sample S in the horizontal direction is D = 0.
mm, the displacement δ of the height of the slit 2
Draws a curve G as shown in FIG. Displacement δ here
That is, when the sample S moves by D = 1 mm,
The displacement amount of the slit 2 to be moved correspondingly. As can be seen from the fact that the sample S has a circumferential shape, the sample S is positioned at the position of the maximum diameter D = 150 mm.
When the sample S moves in the horizontal radial direction, the value of δ is almost close to 0. On the other hand, when the sample S approaches the maximum movement amount of 0, δ
Rapidly increases, and finally becomes a displacement amount exceeding δ = 10 mm.

When the slit dimensions are changed in this manner, the slit dimensions may be changed in a smooth curve along the curve G in FIG. 3 or in a stepwise manner in fine steps along the curve G. The dimensions may be changed. In the present embodiment, the slit height control data from D = 0 to 150 mm as shown in FIG. 3 is prepared assuming that the diameter of the sample S is 300 mm. However, when the size of the sample S is changed, Changes the control data accordingly.

As described above, if the height H of the height limiting slit 2 is changed in accordance with the amount of movement of the sample S in the radial direction, the height of the X-ray irradiation area E with respect to the sample S can be changed. The chordal dimension of the sample S in the X-ray irradiation area E can always be matched, so that it is possible to prevent the X-ray from hitting a portion other than the sample S, for example, the sample holder 4. As a result, it is possible to prevent the occurrence of scattered radiation or the like that adversely affects the measurement from the sample holder 4 or the like, and to obtain a highly reliable measurement result.

The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and can be variously modified within the scope of the invention described in the claims. For example, in the embodiment of FIG. 1, the present invention is applied to an X-ray topographic apparatus based on the Lang method.
Of course, the present invention can be applied to the rg-Barrett method or other various X-ray topographic devices. In FIG. 1, a screw shaft 7 driven and rotated by a pulse motor 8 is used as a structure for adjusting the height of the height limiting slit 2, but any other structure may be used as necessary. Can of course be used. Further, the control data shown in FIG. 3 is one preferable example, and other control data can be used as needed.

[0024]

According to the X-ray topographic apparatus of the present invention, even when the sample size at the X-ray irradiation area changes according to the movement of the sample, the X-ray topography is adjusted in accordance with the change in the size.
The X-ray irradiation area itself can be adjusted.
It is possible to prevent the occurrence of noise elements such as scattered rays that adversely affect the measurement from the portion hit by the line.

According to the X-ray topographic apparatus according to the second and third aspects, the X-ray topographic apparatus according to the first aspect can be simply configured without having a complicated structure, and always operates stably. Obtainable.

According to the X-ray topographic apparatus of the present invention, when a circular sample such as a semiconductor wafer is to be measured, a highly reliable measurement result which is not affected by scattered radiation or the like can be obtained. Can be.

[0027]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of an X-ray topographic apparatus according to the present invention.

FIG. 2 is a perspective view showing a state in which a height dimension of a height limiting slit changes in accordance with a movement of a sample in a radial direction in the apparatus of FIG. 1;

FIG. 3 is a graph showing an example of control data when adjusting a height dimension of a height limiting slit in accordance with a movement of a sample.

FIG. 4 is a diagram schematically illustrating an example of an X-ray topographic apparatus.

FIG. 5 is a perspective view showing a main part of an example of a conventional X-ray topographic apparatus.

FIG. 6 is a perspective view showing a state in which the sample has moved in the radial direction in the apparatus of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 divergence limiting slit 2 height limiting slit 3 width limiting slit 4 sample holder 6 slit holder 7 screw shaft 8 pulse motor 9 control unit 12 high-tensile film 13 slide table 14 transport device D sample moving distance X X-ray irradiation area F X-ray Source S Sample δ Slit displacement

Claims (4)

[Claims] An X-ray source that emits X-rays; a sample moving unit that integrally scans and moves a sample and an X-ray detection unit;
An X-ray topographic apparatus having a height limiting slit for limiting a height in a direction perpendicular to a scanning movement direction of a sample with respect to an X-ray diverging from a source and incident on the sample, wherein the height dimension of the height limiting slit is Is an X-ray topographic apparatus which changes according to the scanning movement of the sample. 2. The X-ray topographic apparatus according to claim 1, wherein a sample moving amount detecting means for detecting a moving amount of the sample, a slit height changing means for changing a height dimension of the height limiting slit, and A control unit for controlling the operation of the slit height changing means based on the output information of the sample movement amount detecting means. 3. The X-ray topographic apparatus according to claim 2, wherein the slit height changing means supports a screw shaft which is driven by a motor and rotates, and which is screw-fitted to the screw shaft and supports the height limiting slit. An X-ray topographic apparatus, comprising: 4. The X-ray topographic apparatus according to claim 1, wherein the sample has a circular shape, and the height of the height limiting slit is such that the X-ray is An X-ray topographic apparatus characterized in that the X-ray topography apparatus is the largest when irradiating a diameter portion of a sample, and becomes smaller as the X-ray irradiation area becomes farther from the diameter portion.