阅读说明：本技术 X射线检查装置 (X-ray inspection apparatus ) 是由 松嶋直树 尾形洁 表和彦 吉原正 伊藤义泰 本野宽 高桥秀明 樋口明房 梅垣志朗 于 2018-09-05 设计创作，主要内容包括：本发明的X射线检查装置具备：试样配置部(11),配置作为检查对象的试样；试样配置部定位机构(30),使试样配置部(11)移动；测角仪(20),包括独立回转的第一、第二回转部件(22、23)；X射线照射单元(40),搭载于第一回转部件(22)；以及二维X射线检测器(50),搭载于第二回转部件(23)。而且,试样配置部定位机构(30)包括以在测定点P与θs轴及θd轴正交并且在水平方向上延伸的χ轴为中心,使试样配置部(11)以及<Image he="63" wi="50" file="DDA0002557688110000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>轴旋转的χ旋转机构(35)。(An X-ray inspection apparatus according to the present invention includes: a sample arrangement unit (11) for arranging a sample to be examined; a sample arrangement part positioning mechanism (30) for moving the sample arrangement part (11); an goniometer (20) including first and second rotating members (22, 23) that rotate independently; an X-ray irradiation unit (40) mounted on the first revolving member (22); and a two-dimensional X-ray detector (50) mounted on the second rotating member (23). The sample arrangement part positioning mechanism (30) includes a sample arrangement part (11) and a chi-axis extending in the horizontal direction and perpendicular to the theta s-axis and the theta d-axis at the measurement point P as a center And a chi-rotation mechanism (35) for rotating the shaft.)

1. An X-ray inspection apparatus, comprising:

a sample arrangement unit for arranging a sample to be examined;

a sample arrangement portion positioning mechanism that moves the sample arrangement portion;

the goniometer comprises a first rotating part and a second rotating part which rotate independently;

an X-ray irradiation unit mounted on the first rotating member and condensing and irradiating X-rays to a predetermined measurement point; and

a two-dimensional X-ray detector mounted on the second rotating member,

the goniometer includes:

a θ s rotating mechanism that rotates the first rotating member around a θ s axis passing through the measurement point and extending in a horizontal direction, and sets an incident angle of the X-ray from the X-ray irradiation unit with respect to the sample disposed at the sample disposition portion; and

a θ d rotation mechanism for rotating the second rotation member around a θ d axis coincident with the θ s axis to set a scanning angle of the X-ray detector,

the sample arrangement portion positioning mechanism includes:

a rotation mechanism for rotating the sample placement unit so as to be orthogonal to the surface of the sampleA shaft as a center for rotating the sample arrangement part;

an X-moving mechanism for moving the sample arrangement part andthe axial direction linearly moves in the X direction which is perpendicularly crossed with the theta s axis and the theta d axis;

a Y-moving mechanism for moving the sample arrangement part andthe axial direction and the Y direction which is right-angle crossed with the X direction move linearly;

a Z-moving mechanism for moving the sample arrangement portion in a Z-direction orthogonal to the surface of the sample arranged in the sample arrangement portion;

a chi-rotation mechanism for rotating the sample arrangement part and the sample arrangement part around a chi-axisAn axis rotation which is orthogonal to the thetas axis and the thetad axis at the measurement point and extends in a horizontal direction; and

a chi-omega rotation mechanism which takes the chi-omega axis as the center to make the sample arrangement part anda rotation axis that rotates around the chi axis by the chi rotation mechanism, the chi ω axis extending orthogonally to the chi axis at the measurement point and parallel to a surface of the sample disposed in the sample disposition portion,

the X-ray irradiation unit has the following structure:

the X-ray is focused in a lateral direction which intersects at right angles with the optical axis of the X-ray and is parallel to the theta s axis, and the X-ray is also focused in a longitudinal direction which intersects at right angles with the optical axis of the X-ray and also intersects at right angles with the theta s axis.

2. X-ray examination apparatus according to claim 1,

the X-ray irradiation means is configured to condense X-rays at the measurement point to a half-value width within 100 μm in the lateral direction and the longitudinal direction, respectively.

3. X-ray examination apparatus according to claim 1 or 2,

the Y-moving mechanism is configured to move the sample arrangement portion in a Y direction parallel to the θ s axis and the θ d axis in a state where the sample arrangement portion is horizontally arranged by the χ -rotating mechanism, and to move the sample arrangement portion in the Y direction, thereby functioning as a sample exchange mechanism for arranging the sample arrangement portion to a preset sample exchange position.

4. The X-ray inspection apparatus according to any one of claims 1 to 3,

a control unit having a control function of controlling the sample arrangement portion positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit to perform in-plane diffraction rocking curve measurement,

the control part comprises the following control functions:

driving the χ -rotating mechanism to vertically arrange the surface of the sample arranged in the sample arrangement portion,

driving the Z-moving mechanism so that the portion to be inspected of the sample placed in the sample placement unit matches the height of the measurement point,

drive theA rotation mechanism, an X-movement mechanism and a Y-movement mechanism for making the examined part of the sample in a preset directionThe position of the point of measurement is located,

further, the θ s rotation mechanism and the χ ω rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from a direction approximately parallel to the surface of the sample,

driving the θ d rotation mechanism in conjunction with the θ s rotation mechanism, and disposing the two-dimensional X-ray detector at a position where the diffracted X-rays emerging from the sample according to Bragg's law are detected,

then, the θ s rotation mechanism is driven to change the incident angle of the X-ray with respect to the sample, thereby performing the rocking curve measurement of in-plane diffraction.

5. The X-ray inspection apparatus according to any one of claims 1 to 3,

a control unit having a control function of controlling the sample arrangement portion positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit to perform in-plane diffraction rocking curve measurement,

the control part comprises the following control functions:

driving the χ -rotating mechanism to vertically arrange the surface of the sample arranged in the sample arrangement portion,

driving the Z-moving mechanism so that the portion to be inspected of the sample placed in the sample placement unit matches the height of the measurement point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the part to be inspected of the sample to the measurement point in a preset direction,

further, the θ s rotation mechanism is driven to irradiate the X-ray from the X-ray irradiation unit from a direction approximately parallel to the surface of the sample,

driving the θ d rotation mechanism in conjunction with the θ s rotation mechanism, and disposing the two-dimensional X-ray detector at a position where the diffracted X-rays emerging from the sample according to Bragg's law are detected,

and driving the sameAnd a rotation mechanism for performing the rocking curve measurement of in-plane diffraction by changing an incident angle of the X-ray with respect to the sample while holding the region to be inspected of the sample at the measurement point by interlocking the X-movement mechanism and the Y-movement mechanism with the drive.

6. The X-ray inspection apparatus according to any one of claims 1 to 3,

a control unit having a control function of controlling the sample arrangement portion positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit to perform in-plane diffraction rocking curve measurement,

the control part comprises the following control functions:

driving the χ -rotating mechanism to vertically arrange the surface of the sample arranged in the sample arrangement portion,

driving the Z-moving mechanism so that the portion to be inspected of the sample placed in the sample placement unit matches the height of the measurement point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the part to be inspected of the sample to the measurement point in a preset direction,

further, the θ s rotation mechanism and the χ ω rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from a direction approximately parallel to the surface of the sample,

driving the θ d rotation mechanism in conjunction with the θ s rotation mechanism, and disposing the two-dimensional X-ray detector at a position where the diffracted X-rays emerging from the sample according to Bragg's law are detected,

the rocking curve measurement of in-plane diffraction is performed in a range of the converging angle of the X-rays converging and incident on the sample from the X-ray irradiation unit.

7. The X-ray inspection apparatus according to any one of claims 1 to 3,

a control unit having a control function of performing in-plane diffraction measurement by controlling the sample arrangement portion positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit,

the control part comprises the following control functions:

driving the χ -rotating mechanism to vertically arrange the surface of the sample arranged in the sample arrangement portion,

driving the Z-moving mechanism so that the portion to be inspected of the sample placed in the sample placement unit matches the height of the measurement point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the part to be inspected of the sample to the measurement point in a preset direction,

further, the θ s rotation mechanism and the χ ω rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from a direction approximately parallel to the surface of the sample,

the θ d rotation mechanism is driven in conjunction with the θ s rotation mechanism, and the two-dimensional X-ray detector is disposed at a position where the diffracted X-rays emerging from the surface of the sample according to bragg's law are detected, thereby performing in-plane diffraction measurement.

8. The X-ray inspection apparatus according to any one of claims 1 to 3,

a control unit having a control function of performing pole measurement by controlling the sample arrangement unit positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit,

the control part comprises the following control functions:

driving the chi-rotation mechanism to rotate the surface of the sample disposed in the sample disposition part around the chi-axis, thereby setting an elevation angle alpha for pole measurement in a range of 0 DEG to 90 DEG, and,

drive theA rotation mechanism for rotating the surface of the sample disposed in the sample disposition part by the rotation of the sampleThe pole measurement is performed by rotating the axis around the center to set an in-plane rotation angle β for the pole measurement.

Technical Field

The present invention relates to an X-ray inspection apparatus suitable for the technical field of manufacturing elements having a multilayer film structure in which a large number of thin films are laminated on a substrate, such as the field of semiconductor manufacturing.

Background

Characteristics of a device having a multilayer film structure in which a large number of thin films are stacked on a substrate, such as a semiconductor, vary depending on the state of the formed thin films, such as film thickness, density, and crystallinity. In recent years, the trend of miniaturization and integration of these elements has been more and more remarkable. Therefore, a thin film inspection apparatus capable of accurately measuring the state of the formed thin film is required.

As such an inspection apparatus, a direct measurement by a cross-sectional Transmission Electron Microscope (TEM), a film thickness inspection apparatus using light interference or an ellipsometer, an acousto-optic apparatus, and the like have been known. In a cross-sectional Transmission Electron Microscope (TEM), so-called on-line inspection for inspecting a thin film to be inspected in real time while being embedded in a manufacturing process cannot be performed, and in reality, a product taken out from a production line for inspection is discarded after inspection. Further, although film thickness inspection apparatuses and acousto-optic apparatuses using optical interference or ellipsometry are suitable for on-line inspection, they are not accurate enough for measuring thin films of several nm.

For semiconductor equipment manufacturers, disposable inspection wafers (blank wafers) are a large burden in terms of cost. In particular, in recent years, the diameter of a semiconductor wafer has been increased, and the cost of one blank wafer has become more expensive.

In view of the above circumstances, the present inventors have heretofore proposed an inline type X-ray thin film inspection apparatus as follows: the inspection method is embedded in a manufacturing process of a film-formed product, and the product itself is directly inspected, and even a thin film of several nm can be inspected with sufficient accuracy without discarding a wafer (see patent document 1).

Disclosure of Invention

Further, in the field of current advanced LSI (Large-Scale Integration), it is necessary to strictly measure lattice distortion, stress, composition ratio, film thickness, and the like of SiGe and compound semiconductors. Further, there is an increasing demand for strictly measuring crystallinity of compound semiconductor thin films of III-V group, II-VI group, and the like used in optical system devices such as LEDs, semiconductor Lasers (LDs), and piezoelectric thin films used in MEMS and the like, and development of X-ray inspection apparatuses that meet these demands is demanded.

In order to cope with these applications and realize efficient inspection In an on-line manner, for example, it is necessary to perform X-ray diffraction measurement for capturing In-plane (In-plane) diffraction among X-ray diffraction, Rocking Curve (Rocking cut) measurement, and the like with high accuracy and high throughput. However, there is no conventional In-line X-ray inspection apparatus that can perform X-ray measurement for capturing In-plane (In-plane) diffraction with high accuracy.

The present invention aims to provide an on-line X-ray inspection apparatus which can be incorporated into a manufacturing process and which can perform X-ray measurement for capturing the in-plane diffraction with high accuracy and high efficiency.

That is, the X-ray inspection apparatus of the present invention includes:

a sample arrangement unit for arranging a sample to be examined;

a sample arrangement portion positioning mechanism for moving the sample arrangement portion;

the goniometer comprises a first rotating part and a second rotating part which rotate independently;

an X-ray irradiation unit mounted on the first rotating member and condensing and irradiating X-rays to a predetermined measurement point; and

and a two-dimensional X-ray detector mounted on the second rotating member.

Here, the goniometer includes:

a θ s rotating mechanism that rotates the first rotating member around a θ s axis passing through the measurement point and extending in the horizontal direction, and sets an incident angle of the X-ray from the X-ray irradiation unit with respect to the sample disposed at the sample disposition portion; and

and a theta-d rotation mechanism for rotating the second rotation member around a theta-d axis coincident with the theta-s axis to set a scanning angle of the X-ray detector.

Further, the sample arrangement portion positioning mechanism includes:

rotating mechanismSo as to be orthogonal to the surface of the sample arranged at the sample arrangement partA shaft as a center for rotating the sample arrangement part;

an X moving mechanism for moving the sample arrangement part andthe axial direction linearly moves in the X direction which is crossed with the theta s axis and the theta d axis at right angles;

y moving mechanism for moving the sample arrangement part andthe axial direction and the Y direction which is right-angle crossed with the X direction move linearly;

a Z-moving mechanism for moving the sample arrangement portion in a Z-direction orthogonal to the surface of the sample arranged in the sample arrangement portion;

a chi-rotation mechanism for rotating the sample arrangement part around the chi-axisAn axis rotation which is orthogonal to the θ s axis and the θ d axis at a measurement point and extends in a horizontal direction; and

a chi-omega rotation mechanism for rotating the sample arrangement part around the chi-omega axisThe axis is rotated and rotated around the chi axis by the chi rotation mechanism, and the chi omega axis is orthogonal to the chi axis at the measurement point and extends parallel to the surface of the sample disposed in the sample disposition part.

Further, the X-ray radiation unit has the following structure:

the X-ray is focused in a lateral direction which intersects at right angles with the optical axis of the X-ray and is parallel to the θ s axis, and the X-ray is also focused in a longitudinal direction which intersects at right angles with the optical axis of the X-ray and also intersects at right angles with the θ s axis.

According to the X-ray inspection apparatus of the present invention having the above configuration, the surface of the sample placed in the sample placement portion is irradiated with the condensed X-rays from the X-ray irradiation unit in a state where the surface is vertically placed by driving the X-ray rotation mechanism, and the incident angle of the X-rays with respect to the sample is changed by the θ s rotation mechanism, whereby the rocking curve measurement of in-plane diffraction can be performed.

Here, since the two-dimensional X-ray detector can collectively detect the diffracted X-rays appearing at a certain range of diffraction angles from the sample surface, the measurement with high throughput can be realized.

Further, since the X-ray irradiation means irradiates the focused X-ray to the microscopic spot on the sample surface, the diffracted X-ray emerging from the microscopic spot is detected, thereby enabling high-resolution and high-precision measurement.

In addition, it is preferable that: the X-ray irradiation unit is configured to condense X-rays at a measurement point in the lateral direction and the longitudinal direction to a half-value width within 100 [ mu ] m.

Preferably, the Y-moving mechanism is configured to move the sample arrangement portion in a direction (Y direction) parallel to the θ s axis and the θ d axis in a state where the sample arrangement portion is horizontally arranged by the χ -rotating mechanism. According to such a configuration, the Y moving mechanism can also function as a sample replacement mechanism for moving (horizontally moving) the sample arrangement portion in the Y direction to arrange the sample arrangement portion at a preset sample replacement position.

Further, the direction in which the sample arrangement portion is moved by the Y moving mechanism (i.e., the Y direction) is parallel to the θ s axis which is the rotation center of the first rotating member and the θ d axis which is the rotation center of the second rotating member, so that the sample arrangement portion can be horizontally moved to the sample exchange position without interfering with the rotation trajectory of the X-ray irradiation unit mounted on the first rotating member and the rotation trajectory of the two-dimensional X-ray detector mounted on the second rotating member. Therefore, it is possible to realize so-called online X-ray inspection, in which a thin film to be inspected is embedded in a manufacturing process of a film-formed product and inspected in real time.

On the other hand, since the Y-moving mechanism functions as a sample replacing mechanism, the moving distance in the Y direction becomes long, and the movement is connected toAs a result, it is undeniable that the Y-moving mechanism will be large-sized. Therefore, in the X-ray inspection apparatus of the present invention, the Y-moving mechanism is mounted on the X-ray inspection apparatusRotation mechanism to thereby reduce drivingTorque required to rotate the mechanism. Thereby, can realizeMiniaturization of the rotary mechanism and smooth driving at low power.

The X-ray inspection apparatus of the present invention includes a control unit having a control function of performing in-plane diffraction rocking curve measurement by controlling a sample arrangement unit positioning mechanism, a goniometer including a first rotating member and a second rotating member, and an X-ray irradiation unit.

In this case, the control unit includes the following control functions:

the chi-rotation mechanism is driven to vertically arrange the surface of the sample arranged in the sample arrangement part,

the Z-moving mechanism is driven to make the examined part of the sample arranged at the sample arrangement part match the height of the measuring point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the inspected part of the sample to the measuring point in a preset direction,

further, the theta-s rotation mechanism and the chi-omega rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from the direction approximately parallel to the surface of the sample,

a two-dimensional X-ray detector is disposed at a position where the two-dimensional X-ray detector detects the diffracted X-rays appearing from the sample according to Bragg's law by driving the theta d rotation mechanism in conjunction with the theta s rotation mechanism,

then, the θ s rotation mechanism is driven to change the incident angle of the X-ray with respect to the sample, thereby measuring the rocking curve of in-plane diffraction.

The control unit may be configured as follows.

That is, the control unit may be configured to have the following control functions:

the chi-rotation mechanism is driven to vertically arrange the surface of the sample arranged in the sample arrangement part,

the Z-moving mechanism is driven to make the examined part of the sample arranged at the sample arrangement part match the height of the measuring point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the inspected part of the sample to the measuring point in a preset direction,

further, the theta-s rotation mechanism is driven to irradiate the X-ray from the X-ray irradiation unit from a direction approximately parallel to the surface of the sample,

a two-dimensional X-ray detector is disposed at a position where the two-dimensional X-ray detector detects the diffracted X-rays appearing from the sample according to Bragg's law by driving the theta d rotation mechanism in conjunction with the theta s rotation mechanism,

and, driveAnd a rotation mechanism for performing the rocking curve measurement of in-plane diffraction by changing the incident angle of the X-ray with respect to the sample while holding the region to be inspected of the sample at the measurement point by interlocking the X-movement mechanism and the Y-movement mechanism with the drive.

Further, the control unit may be configured as follows.

That is, the control unit may be configured to include the following control functions:

the chi-rotation mechanism is driven to vertically arrange the surface of the sample arranged in the sample arrangement part,

the Z-moving mechanism is driven to make the examined part of the sample arranged at the sample arrangement part match the height of the measuring point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the inspected part of the sample to the measuring point in a preset direction,

further, the theta-s rotation mechanism and the chi-omega rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from the direction approximately parallel to the surface of the sample,

a two-dimensional X-ray detector is disposed at a position where the two-dimensional X-ray detector detects the diffracted X-rays appearing from the sample according to Bragg's law by driving the theta d rotation mechanism in conjunction with the theta s rotation mechanism,

the rocking curve measurement of in-plane diffraction is performed in the range of the collection angle of the X-rays collected and incident from the X-ray irradiation unit on the sample.

With such a configuration, the incidence angle of the X-ray with respect to the sample is changed or driven without driving the θ s rotation mechanismRotating the mechanism to make the sample in the in-plane direction (Direction) of the diffraction pattern, the rocking curve measurement of in-plane diffraction can be performed in a short time, and the measurement at high throughput can be realized.

The X-ray inspection apparatus of the present invention further includes a control unit having a control function of performing in-plane diffraction measurement by controlling the sample arrangement unit positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit.

Here, the control unit is configured to include the following control functions:

the chi-rotation mechanism is driven to vertically arrange the surface of the sample arranged in the sample arrangement part,

the Z-moving mechanism is driven to make the examined part of the sample arranged at the sample arrangement part match the height of the measuring point,

drive theA rotation mechanism, an X movement mechanism and a Y movement mechanism for positioning the inspected part of the sample to the measuring point in a preset direction,

further, the theta-s rotation mechanism and the chi-omega rotation mechanism are driven to irradiate the X-ray from the X-ray irradiation unit from the direction approximately parallel to the surface of the sample,

the θ d rotation mechanism is driven in conjunction with the θ s rotation mechanism, and a two-dimensional X-ray detector is disposed at a position where the diffracted X-rays emerging from the surface of the sample according to bragg's law are detected, thereby performing in-plane diffraction measurement.

The X-ray inspection apparatus of the present invention further includes a control unit having a control function of controlling the sample placement unit positioning mechanism, the goniometer including the first and second rotating members, and the X-ray irradiation unit to perform pole measurement.

In this case, the control unit includes the following control functions:

the surface of the sample disposed in the sample arrangement part is rotated around the chi axis by driving the chi rotation mechanism, so that the elevation angle alpha of the pole measurement is set in the range of 0 DEG to 90 DEG, and,

drive theA rotation mechanism for rotating the surface of the sample disposed in the sample arrangement partThe pole measurement is performed by rotating the axis around the center to set an in-plane rotation angle β for the pole measurement.

According to the present invention, the X-ray measurement for capturing in-plane diffraction can be performed on-line with high accuracy and high efficiency by being incorporated in a manufacturing process.

Drawings

Fig. 1A is a front view showing the overall configuration of an X-ray inspection apparatus of an embodiment of the present invention. Fig. 1B is a side view of the entire configuration of the X-ray inspection apparatus.

Fig. 2A is a front view schematically showing the main configuration of an X-ray inspection apparatus according to an embodiment of the present invention. Fig. 2B is a side view of the main configuration of the X-ray inspection apparatus.

FIG. 3 is a view schematically showing the moving direction in which the sample arrangement portion is moved by the sample arrangement portion positioning mechanism.

Fig. 4A is a front view schematically showing the structure of an X-ray irradiation unit of an embodiment of the present invention. Fig. 4B is a bottom view of the structure of the X-ray irradiation unit.

Fig. 5 is a perspective view of the X-ray irradiation unit shown in fig. 4A and 4B.

Fig. 6A is an enlarged front view illustrating the first X-ray optical element and the second X-ray optical element included in the X-ray irradiation unit illustrated in fig. 4A, 4B, and 5. Fig. 6B is a bottom view of the first and second X-ray optic.

Fig. 7A is a front view schematically showing a trajectory of X-rays irradiated from the X-ray irradiation unit to the inspection surface of the semiconductor wafer, and a trajectory of diffracted X-rays reflected from the inspection surface and incident on the X-ray detector. Fig. 7B is an enlarged plan view of a portion of the measurement point P in fig. 7A.

Fig. 8 is a block diagram showing a control system (control unit) of the X-ray inspection apparatus according to the embodiment of the present invention.

Fig. 9 is a conceptual diagram for explaining in-plane X-ray diffraction measurement.

Fig. 10A is a front view corresponding to fig. 2 for explaining a procedure of performing in-plane X-ray diffraction measurement by the X-ray inspection apparatus according to the embodiment of the present invention. Fig. 10B is a corresponding side view.

Fig. 11 is a schematic diagram corresponding to fig. 3 for explaining a procedure of performing in-plane X-ray diffraction measurement by the X-ray inspection apparatus according to the embodiment of the present invention.

Fig. 12 is a conceptual diagram for explaining the rocking curve measurement of in-plane diffraction.

Fig. 13 is a conceptual diagram for explaining the pole measurement.

Fig. 14A is a front view schematically showing another configuration example of the X-ray inspection apparatus according to the embodiment of the present invention. Fig. 14B is a corresponding side view.

(symbol description)

S: a sample; p: measuring points; 10: a sample stage; 11: a sample arrangement part; 20: an angle gauge; 21: a goniometer body; 22: a first swivel arm; 23: a second swing arm; 30: a positioning mechanism; 31:a rotation mechanism; 32: an X moving mechanism; 33: a Y moving mechanism; 34: a Z moving mechanism; 35: a χ -rotation mechanism; 36: a χ ω rotation mechanism; 40: an X-ray irradiation unit; 41: an X-ray tube; 42: a first X-ray optic; 43: a second X-ray optic; 44: a light-gathering slit; 50: an X-ray detector; 100: a central processing device; 101: an XG controller; 102: a positioning controller; 103: an angle controller; 104: a count control circuit; 110: a storage unit; 201: an operation section; 202: a display unit; 203: a communication unit.

Detailed Description

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

[ basic structure of X-ray inspection apparatus ]

Fig. 1A and 1B are diagrams illustrating an overall configuration of an X-ray inspection apparatus according to an embodiment of the present invention. Fig. 2A and 2B are diagrams schematically showing the main structure of the apparatus.

As shown in these figures, the X-ray inspection apparatus according to the embodiment of the present invention includes a sample stage 10, a goniometer 20, a sample placement portion positioning mechanism (hereinafter, also simply referred to as "positioning mechanism") 30, an X-ray irradiation unit 40, and an X-ray detector 50.

A sample arrangement portion 11 is formed on the upper surface of the sample stage 10. A semiconductor wafer (sample S) to be inspected is disposed in the sample disposition portion 11. The sample stage 10 is driven by a positioning mechanism 30. The X-ray inspection apparatus is preset with a measurement point P. Then, the positioning mechanism 30 drives the sample stage 10 to position the site of measurement of the sample S disposed in the sample arrangement portion 11 to the measurement point P.

The sample arrangement portion 11 is provided with a mechanism (not shown) for fixing the sample S. With this sample fixing mechanism, even when the surface of the sample arrangement portion 11 (the upper surface of the sample stage 10) is vertically arranged as described later, the sample S can be prevented from falling off from the sample arrangement portion 11.

As the fixing mechanism of the sample S, for example, the following structure can be adopted: a plurality of suction nozzles are opened on the surface of the sample arrangement portion 11, and the inside of the hollow portions of the suction nozzles are vacuum-sucked by a suction device such as a vacuum pump, thereby sucking the sample S on the surface of the sample arrangement portion 11. Of course, other known sample fixing mechanisms may be used.

The goniometer 20 incorporates a θ s rotation mechanism and a θ d rotation mechanism in a goniometer body 21.

The θ s turning mechanism turns the first turning arm (turning member) 22 in the direction of the arrow θ s in fig. 2A around the θ s axis extending in the horizontal direction and passing through a predetermined measurement point P. An X-ray irradiation unit 40 is mounted on the first swing arm 22. Then, the incident angle of the X-ray from the X-ray irradiation unit 40 with respect to the sample S is set by the movement of the first rotating arm 22.

The θ d turning mechanism turns the second turning arm (turning member) 23 in the direction of the arrow θ d in fig. 2A around the θ d axis extending in the horizontal direction and passing through the preset measurement point P. An X-ray detector 50 is mounted on the second swing arm 23. Then, the scanning angle of the X-ray detector 50 is set by the movement of the first swing arm 22. That is, the X-ray detector 50 is disposed at a position for detecting the diffracted X-rays emerging from the surface of the sample S according to bragg law by the movement of the first rotating arm 22.

The axis θ s and the axis θ d are coaxial rotation center axes.

The positioning mechanism 30 includes: for moving the sample arrangement part 11 in each directionA rotation mechanism 31, an X movement mechanism 32, a Y movement mechanism 33, a Z movement mechanism 34, a χ rotation mechanism 35, and a χ ω rotation mechanism 36.

FIG. 3 is a view schematically showing the moving direction in which the sample arrangement part 11 is moved by the positioning mechanism 30. The positioning mechanism 30 is described with reference to fig. 2A and 2B.

The rotation mechanism 31 is arranged so as to be orthogonal to the surface of the sample S arranged in the sample arrangement part 11The axis is the center, and the sample arrangement part 11 is directed toward the arrow of the figureIs rotated.

The X-moving mechanism 32 moves the sample arrangement part 11 andthe axis moves linearly in the X direction which intersects with the theta s axis and the theta d axis at right angles.

The Y-moving mechanism 33 moves the sample arrangement part 11 andthe axial direction is linearly moved in the Y direction which is orthogonal to the X direction.

The Z-moving mechanism 34 moves the sample arrangement portion 11 in the Z-direction perpendicular to the surface of the sample S arranged in the sample arrangement portion 11.

A chi-rotation mechanism 35 for centering on the chi-axis and arranging the sample arrangement part 11 andthe axis view is rotated in the direction of arrow χ, which extends in the horizontal direction at the measurement point P, perpendicular to the θ s axis and the θ d axis.

The chi-omega rotation mechanism 36 uses the chi-omega axis as the center to make the sample arrangement part 11 andthe axis view is rotated in the direction of an arrow χ ω extending perpendicular to the χ axis at the measurement point P and parallel to the surface of the sample disposed in the sample disposition portion 11. Further, the χ ω rotation mechanism 36 is rotated in the direction of arrow χ in the χ axial direction by the χ rotation mechanism 35.

In addition, a sample replacement position (not shown) is set in advance in the X-ray inspection apparatus. The sample arrangement portion 11 formed on the upper surface of the sample stage 10 is transported to the sample replacement position. At the sample replacement position, the sample S to be tested is taken out from the sample arrangement portion 11 by a sample replacement device (not shown) such as a robot arm, and a new sample S to be tested is arranged in the sample arrangement portion 11.

In the X-ray inspection apparatus of the present embodiment, the Y-moving mechanism 33 functions as a sample exchange mechanism for moving the sample arrangement portion 11 to the sample exchange position.

Here, the configuration is: in a state where the sample arrangement portion 11 is horizontally arranged by the χ -rotation mechanism 35, the direction in which the sample arrangement portion 11 is moved (Y direction) is parallel to the θ s axis and the θ d axis. Then, a sample replacement position is set on a movement path for moving the sample arrangement portion 11 in this direction.

By moving the sample arrangement part 11 in the direction parallel to the θ s axis and the θ d axis in this way, the sample arrangement part 11 can be moved to the sample replacement position without interfering with the first swing arm 22 on which the X-ray irradiation unit 40 is mounted and the second swing arm 23 on which the X-ray detector 50 is mounted.

On the other hand, the Y-moving mechanism 33 has a function as a sample replacement mechanism, and the moving distance in the Y direction becomes long, and as a result, it is undeniable that the Y-moving mechanism 33 becomes large. Therefore, in the X-ray inspection apparatus of the present embodiment, the Y-moving mechanism 33 is mounted thereonRotation of the mechanism 31 to reduce driveThe torque required to rotate the mechanism 31. Thereby, can realizeThe rotation mechanism 31 is miniaturized and can be driven smoothly with a small power.

As shown in fig. 1A to 2B, the X-ray inspection apparatus according to the present embodiment is configured such that: the chi-rotation mechanism 35 is provided with a chi- ω rotation mechanism 36, an X-movement mechanism 32, a Y-movement mechanism 33, a Z-movement mechanism 34,A rotation mechanism 31 and a sample stage 10. Specifically, the χ ω rotation mechanism 36 is configured to rotate around the χ axis by the χ rotation mechanism 35. The χ ω rotation mechanism 36 is mounted with an X movement mechanism 32 and a Y movement mechanism 33. Further, a Z-movement mechanism 34 is mounted on the Y-movement mechanism 33. Further, the Z-moving mechanism 34 is mounted thereonAnd a rotating mechanism 31. Further, it is set asThe rotating mechanism 31 is provided with a sample stage 10.

The X-ray irradiation unit 40 has the following functions: an X-ray generated from an X-ray tube is monochromated into a characteristic X-ray of a specific wavelength and condensed to one portion.

The X-ray irradiation unit 40 adjusts an irradiation trajectory of the X-ray so as to irradiate the X-ray to a measurement point P set in advance in a converging manner. As described above, the site to be measured of the sample S disposed in the sample arrangement portion 11 is positioned at the measurement point P.

The detailed structure of the X-ray radiation unit 40 will be described later.

As the X-ray detector 50, a two-dimensional X-ray detector is used. The two-dimensional X-ray detector includes a planar X-ray detection unit configured two-dimensionally, and can record all of the diffracted X-rays appearing on the surface of the sample S onto the planar X-ray detection unit. Therefore, the time required for measurement can be shortened as compared with a one-dimensional X-ray detector such as a Proportional Counter (PC) or a Scintillation Counter (SC).

In recent years, the following two-dimensional semiconductor detectors have also been developed: in the X-ray detection unit, a large number of silicon semiconductor elements having a very small pixel size of 100 μm or less are arranged, and X-rays can be detected with high positional resolution in a short time and with high accuracy by using these semiconductor elements. By using such a two-dimensional semiconductor detector as the X-ray detector 50, an online high-efficiency and high-precision X-ray inspection in the manufacturing process can be realized.

[ construction example of X-ray irradiation Unit ]

Next, the X-ray irradiation unit will be described in detail with reference to fig. 4A to 7B.

The X-ray irradiation unit 40 shown in fig. 4A to 7B includes, as components, an X-ray tube 41, a first X-ray optical element 42, a second X-ray optical element 43, and a condensing slit 44 (slit member). These components are built in a unit main body not shown. The unit body has a compact size and shape that can be mounted on the first swing arm 22.

Note that only the light collecting slit 44 is shown in fig. 7A, and the light collecting slit 44 is omitted in fig. 4A, 4B, and 5.

As the X-ray tube 41, for example, an electron beam focal spot size on a target ofLeft and right tiny focus X-ray tube balls. As the target material, copper (Cu), molybdenum (Mo), iron (Fe), cobalt (Co), tungsten (W), chromium (Cr), silver (Ag), gold (Au), or the like can be selected as necessary.

In particular, if copper (Cu) is used as the target material, only characteristic X-rays of Cu — K α 1 having high angular resolution can be extracted by the first X-ray optical element 42 and the second X-ray optical element 43, which will be described later. Therefore, by irradiating the sample with the characteristic X-ray of Cu — K α 1, an X-ray thin film inspection with good throughput can be realized.

The first and second X-ray optical elements 42 and 43 have the following functions: the X-ray a1 emitted from the X-ray tube 41 is incident, and only the characteristic X-ray of a specific wavelength is extracted, and the extracted characteristic X-ray a2 is condensed on the surface of the sample disposed on the sample stage 10.

As shown in fig. 4A to 7B, the first X-ray optical element 42 and the second X-ray optical element 43 are arranged with surfaces (hereinafter simply referred to as "surfaces") 42a, 43a that are orthogonal to each other and that incident X-rays and reflect characteristic X-rays. As shown in fig. 7A, the first X-ray optical element 42 and the second X-ray optical element 43 condense characteristic X-rays a2 of a specific wavelength into a quadrangular microscopic spot on the surface of the sample placed on the sample stage 10. Fig. 7B is an enlarged plan view schematically showing a position on the surface of the sample (semiconductor wafer) where the characteristic X-ray a2 is condensed.

In the present embodiment, the first X-ray optical element 42 and the second X-ray optical element 43 are arranged in a Side-by-Side manner in which 1 Side is in contact with each other, but the present invention is not limited thereto, and may be arranged in a serial manner called Kirkpatrick-baez (kb).

The position at which the characteristic X-rays reflected and extracted by the first X-ray optical element 42 and the second X-ray optical element 43 are condensed on the surface of the sample disposed on the sample stage 10 is a measurement point P. In this way, the surfaces 42a and 43a of the X-ray optical elements 42 and 43 are curved to form a concave shape in order to condense the characteristic X-rays to the measurement point P.

Here, the first X-ray optical element 42 condenses the X-ray in a vertical direction orthogonal to the optical axis of the X-ray and orthogonal to the θ s axis.

On the other hand, the second X-ray optical element 43 condenses the X-ray in a lateral direction perpendicular to the optical axis of the X-ray and parallel to the θ s axis.

Further, the first X-ray optical element 42 is made of a crystalline material having high crystallinity. In other words, the first X-ray optical element 42 is made of a crystalline material having an extremely small intrinsic rocking curve width (i.e., an angular range capable of reflecting a parallel beam). As a crystal material having such a very small intrinsic rocking curve width, a crystal material corresponding to a perfect crystal having very few lattice defects and impurities can be used.

In the present embodiment, the material is made of a crystalline material having a specific rocking curve width of 0.06 ° or less. By using the characteristic X-ray a2 extracted from the crystalline material, a high angular resolution of 0.06 ° or less can be obtained in the X-ray thin film measurement.

As the crystalline material, Ge (111) or Si (111) can be used, for example. In the case of using Ge (111), a rocking curve width of 0.06 ° or less was obtained. In addition, when Si (111) is used, a rocking curve width of 0.02 ° or less is obtained.

Further, according to the first X-ray optical element 42, the X-rays can be condensed to a half-value width within 100 μm in the longitudinal direction at the measurement point P.

The first X-ray optical element 42 has a function of extracting only characteristic X-rays having a specific wavelength and making them monochromatic.

On the other hand, the second X-ray optical element 43 is constituted by a multilayer film mirror. The second X-ray optical element 43 has a function of extracting only characteristic X-rays of a specific wavelength and making them monochromatic. Here, the characteristic X-rays having the same wavelength as the characteristic X-rays extracted by the first X-ray optical element 42 are extracted from the second X-ray optical element 43.

Further, according to the second X-ray optical element 43, the X-rays can be converged to a half-value width within 100 μm in the lateral direction at the measurement point P.

As shown in fig. 6A and 6B in an enlarged manner, the X-ray B1 emitted from the X-ray tube 41 and incident on the surface 43a of the second X-ray optical element 43 is monochromatized and reflected by the X-ray optical element 43, advances in a condensed manner in the lateral direction, and then enters the surface 42a of the first X-ray optical element 42. Then, the X-ray B2 incident on the front surface 42a of the first X-ray optical element 42 is also monochromatized and reflected by the X-ray optical element 42, and travels so as to be condensed in the longitudinal direction, and is irradiated to the measurement point P shown in fig. 4A and 4B.

On the other hand, the X-ray c1 emitted from the X-ray tube 41 and incident on the surface 42a of the first X-ray optical element 42 is monochromatized and reflected by the X-ray optical element 42, travels to be condensed in the longitudinal direction, and then is incident on the surface 43a of the second X-ray optical element 43. Then, the X-ray c2 incident on the front surface 43a of the second X-ray optical element 43 travels so as to be condensed in the lateral direction, and is irradiated to the measurement point P shown in fig. 4A and 4B.

In this way, the X-ray a1 emitted from the X-ray tube 41 is reflected 1 time on the surface 42a of the first X-ray optical element 42 and the surface 43a of the second X-ray optical element 43, respectively, and only the characteristic X-ray a2 of a specific wavelength is extracted in the process, and the characteristic X-ray a2 is condensed to the measurement point P.

Patent documents 2 and 3 describe an X-ray beam adjustment system combining a complete crystal and a multilayer optical component. However, these documents do not disclose a configuration most suitable for an X-ray inspection apparatus using a semiconductor wafer as a sample to be inspected.

The condensing slit 44 is disposed so as to shield a part of the characteristic X-ray a2 reflected by the first X-ray optical element 42 and the second X-ray optical element 43 from both sides in the longitudinal direction. The condensing slit 44 has a function of limiting the longitudinal condensing of the condensed X-ray a2 reflected by the first X-ray optical element 42 and the second X-ray optical element 43.

According to the X-ray inspection apparatus in which the X-ray irradiation unit 40 having the above-described configuration is mounted on the first rotating arm 22, the X-rays can be condensed in a minute region by the first X-ray optical element 42, the second X-ray optical element 43, and the condensing slit 44. Therefore, the thin film measurement can be performed by irradiating an extremely minute inspection region on the surface of the semiconductor wafer with X-rays. Further, since the first X-ray optical element 42 is made of a crystalline material having an extremely small oscillation curve width, it is possible to obtain an extremely high angular resolution in the X-ray thin film measurement by using the characteristic X-ray a2 extracted from the crystalline material.

[ control system for X-ray inspection apparatus ]

Fig. 8 is a block diagram showing a control system (control unit) of the X-ray inspection apparatus.

An XG (X-ray Generator) controller 101 performs control of the X-ray irradiation unit 40.

The positioning controller 102 controls driving of the positioning mechanism 30.

The goniometer 20 is driven and controlled by an angle controller 103.

Each component of the XG controller 101, the positioning controller 102, and the angle controller 103 operates based on the setting information transmitted from the Central Processing Unit (CPU) 100. Here, the setting information is stored in the storage unit 110 as the arrangement data (recipe), and is read out by the Central Processing Unit (CPU)100 and output to the above-described components.

The X-ray detector 50 is controlled by a count control circuit 104.

These components and the central processing unit 100 are configured by a computer, are installed in the storage unit 110 in advance, and execute respective control operations in accordance with a control program.

The X-ray inspection apparatus includes an operation unit 201 including a keyboard, a mouse, and the like, and an operator inputs various settings necessary for the operation of the apparatus. Further, the X-ray inspection apparatus includes: a display unit 202 configured by a liquid crystal display or the like, and a communication unit 203 for performing data communication via a network.

[ in-plane X-ray diffraction measurement ]

Next, the function of in-plane X-ray diffraction measurement provided by the X-ray inspection apparatus having the above-described configuration will be described.

As shown in fig. 9, the in-plane X-ray diffraction measurement is as follows: x-rays a are incident almost close to the surface of the thin film sample S, and diffracted X-rays b are measured in which the crystal lattice plane orthogonal to the surface in the thin film sample S is diffracted according to bragg' S law. By this in-plane X-ray diffraction measurement, information on the size and orientation of crystals in the direction perpendicular to the surface of the thin film sample S can be obtained.

The control system (control section) shown in fig. 8 includes the following control functions: the positioning mechanism 30, the goniometer 20, and the X-ray irradiation unit 40 are controlled to perform in-plane diffraction measurement

That is, a control program for performing in-plane X-ray diffraction measurement is installed in advance in the storage unit 110 of the control system (control unit) shown in fig. 8. Further, the storage unit 110 stores setting information necessary for in-plane X-ray diffraction measurement as arrangement data in advance. The Central Processing Unit (CPU)100 reads necessary setting information in accordance with the control program, and outputs the setting information to each component of the control system.

Specifically, as shown in fig. 10A, 10B, and 11, in-plane diffraction measurement can be performed in a state where the surface of the sample S disposed in the sample disposition portion 11 is disposed vertically.

That is, the positioning controller 102 controls the driving of the χ -turn mechanism 35 constituting the positioning mechanism 30 so that the surface of the sample S disposed in the sample disposition portion 11 is disposed vertically.

Next, the positioning controller 102 controls the driving of the Z-moving mechanism 34 so that the portion to be inspected of the sample S disposed in the sample arrangement portion 11 matches the height of the measurement point P. Further, the pair of positioning controllers 102The rotation mechanism 31, the X movement mechanism 32, and the Y movement mechanism 33 are driven and controlled to position the portion to be inspected of the sample S to the measurement point P in a predetermined direction.

Further, the positioning controller 102 controls the driving of the χ ω rotating mechanism 36 so that the incident X-ray a from the X-ray irradiation unit 40 is made incident on the surface of the sample S at a nearly contact angle (Δ ω). The purpose of setting the angle of incidence of the X-ray a with respect to the surface of the sample S in this manner is to irradiate the crystal lattice plane with the X-ray from the surface of the sample S in a state of low absorption.

The angle controller 103 controls the driving of the θ S rotation mechanism of the goniometer 20, and sets the incident angle of the X-ray a from the X-ray irradiation unit 40 with respect to the sample S.

In this state, the XG controller 101 controls the X-ray irradiation unit 40 to irradiate the X-ray a toward the specimen S. Inside the sample S, X-rays are diffracted according to bragg' S law on a crystal lattice plane perpendicular to the sample surface. Then, the diffracted X-ray b emerges from the surface of the sample S.

The angle controller 103 controls the driving of the θ d rotation mechanism of the goniometer 20, and arranges the X-ray detector 50 at a position for detecting the diffracted X-rays b emerging from the surface of the sample S. The X-ray detector 50 is controlled by the count control circuit 104 to detect the diffracted X-rays b.

According to the X-ray inspection apparatus of the present embodiment, the X-ray irradiation unit 40 can irradiate the sample S with the X-rays a condensed to a minute area at a high resolution, and therefore, the sample S can be irradiated with the X-ray beams a in the condensed angle range at a time to perform the X-ray diffraction measurement. Further, the two-dimensional X-ray detector is used as the X-ray detector 50, and the X-ray beam b diffracted in a certain angle range can be detected together with the X-ray beam a in the condensed angle range, thereby shortening the measurement time.

[ rocking curve measurement of in-plane diffraction ]

Next, a function of the rocking curve measurement of in-plane diffraction provided in the X-ray inspection apparatus having the above-described configuration will be described.

As described above, as shown in fig. 9, in-plane diffraction is a diffraction phenomenon that X-rays incident on a crystal lattice plane orthogonal to the surface of the thin film sample S are generated in accordance with bragg' S law in the lattice plane.

By performing the rocking curve measurement focusing on the in-plane diffraction, the orientation of the sample S having the in-plane orientation can be evaluated. That is, as shown in FIG. 12, the sample S is arranged in the in-plane direction (A)Direction) of the crystal is rotated by a minute angle to perform a rocking curve measurement, and the degree of deviation of the crystal orientation in the rotational orientation can be evaluated.

Specifically, the X-ray detector 50 is fixed to: when X-rays are incident on a crystal lattice plane orthogonal to the surface of the thin film sample S at an angle θ, the X-rays are diffracted from the lattice plane according to bragg' S law (direction of the incident X-rays)The optical axis is in the angular direction of 2 θ). In this state, the sample S is oriented in the in-plane direction (Direction) is rotated a slight angle to perform a rocking curve measurement.

The control system (control section) shown in fig. 8 includes the following control functions: the positioning mechanism 30, the goniometer 20, and the X-ray irradiation unit 40 are controlled to perform rocking curve measurement of in-plane diffraction.

That is, the storage unit 110 of the control system (control unit) shown in fig. 8 is provided with a control program for performing the rocking curve measurement of in-plane diffraction, and setting information necessary for the measurement is stored in advance as arrangement data. The Central Processing Unit (CPU)100 reads out necessary setting information in accordance with the control program, and outputs the setting information to each component of the control system.

Specifically, as shown in fig. 10A, 10B, and 11, the rocking curve measurement of in-plane diffraction can be performed in a state where the surface of the sample disposed in the sample disposition portion 11 is disposed vertically.

That is, the positioning controller 102 controls the driving of the χ -turn mechanism 35 constituting the positioning mechanism 30 so that the surface of the sample placed in the sample placement unit 11 is vertically placed.

Next, the positioning controller 102 controls the driving of the Z-moving mechanism 34 so that the portion to be inspected of the sample S disposed in the sample arrangement portion 11 matches the height of the measurement point P. Further, the pair of positioning controllers 102The rotation mechanism 31, the X movement mechanism 32, and the Y movement mechanism 33 are driven and controlled to position the portion to be inspected of the sample S to the measurement point P in a predetermined direction.

Further, the positioning controller 102 controls the driving of the χ ω rotating mechanism 36 so that the incident X-ray from the X-ray irradiation unit 40 is incident on the surface of the sample S at a nearly contact angle (Δ ω).

The angle controller 103 controls the driving of the θ S rotation mechanism of the goniometer 20, and sets the incident angle of the X-ray a from the X-ray irradiation unit 40 with respect to the sample S. At the same time, the angle controller 103 controls the driving of the θ d rotation mechanism of the goniometer 20, and arranges the X-ray detector 50 at a position for detecting the diffracted X-rays emerging from the sample S according to the bragg law.

In this state, the XG controller 101 controls the X-ray irradiation unit 40 to irradiate the X-ray a toward the specimen S. Then, the count control circuit 104 controls the X-ray detector 50, and detects the diffracted X-rays b emerging from the surface of the sample S by the X-ray detector 50.

Further, the angle controller 103 drives and controls the θ S rotation mechanism of the goniometer 20 to change the incident angle of the X-ray with respect to the sample S. The operation of changing the incident angle corresponds to the operation of orienting the sample S in the in-plane direction (see fig. 12)Direction) of a slight angle of rotation. By this operation, the rocking curve measurement of in-plane diffraction was performed.

In addition, the positioning controller 102 is used to align the positions shown in fig. 10A, 10B, and 11The rotation mechanism 31 is controlled to be driven, and the X-movement mechanism 32 and the Y-movement mechanism 33 are controlled to be interlocked with the driving, so that the sample S can be moved in the in-plane direction (in fig. 12)Direction) of a slight angle of rotation.

The X-ray inspection apparatus of the present embodiment having the above-described configuration is provided directly below the sample table 10Since the rotation mechanism 31 (see fig. 2A and 2B) is driven and controlled by the X-and Y-movement mechanisms 32 and 33 to position the site to be measured of the sample S at the measurement point P,the rotating mechanism 31 moves in the XY directions together with the sample S, andthe axis may be deviated from the measurement point P. Therefore, it is necessary to deviate from the measurement point PThe rotation angle of the measurement point P when the axis is rotated by a slight angle as the center is corrected to a rotation angle without such a deviation.

Thus, by reacting withThe rotation mechanism 31 drives and controls the X-movement mechanism 32 and the Y-movement mechanism 33 together in an interlocking manner, and corrects the directionAnd (4) rotating the direction.

Further, according to the X-ray inspection apparatus of the present embodiment, since the X-ray a condensed in a minute area can be irradiated to the sample S with high resolution by the X-ray irradiation unit 40, the X-ray diffraction measurement can be performed by irradiating the sample S with the X-ray a beams in the condensed angle range at once. Further, by using a two-dimensional X-ray detector as the X-ray detector 50, it is possible to collectively detect a bundle of diffracted X-rays b diffracted in a certain angle range corresponding to the bundle of X-rays a in the condensed angle range. Therefore, it is not necessary to make the sample S in the in-plane direction (S) as shown in fig. 12Direction) of the diffraction pattern, and a rocking curve measuring method in which in-plane diffraction can be performed in a relatively short time.

In general, in a rocking curve measuring method for a sample S in which a thin film crystal is epitaxially grown on a substrate crystal, an incident angle θ of X-rays to a sample surface is changed within a range of 2 ° or more. Therefore, it is preferable that the X-ray irradiated from the X-ray irradiation unit 40 to the surface of the sample is set to a condensing angle of 2 ° or more by the condensing slit 44, and the X-ray in the angular range of 2 ° or more is irradiated to the surface of the sample.

In addition, as described above, the sample S is oriented in the in-plane direction (i)Direction) of the X-ray beam, a slit or the like may be provided to reduce the X-ray beam applied to the sample S.

[ concrete examples of rocking curve measurement of in-plane diffraction ]

The X-ray inspection apparatus of the present invention can perform a rocking curve measurement using in-plane diffraction, for example, on a SiGe (silicon germanium) epitaxial thin film or the like formed on a substrate.

For example, according to the X-ray inspection apparatus of the present invention, SiO formed on a silicon substrate can be inspected₂The measurement of the rocking curve of in-plane diffraction was carried out as follows, with a SiGe on Insulator (SGOI) thin film on the thin film being the measurement target.

For example, a SiGe thin film is crystal-grown on a silicon substrate having an Si (100) plane parallel to the substrate surface, and then irradiated with oxygen ions and subjected to a high-temperature treatment under appropriate conditions to form SiO between the silicon substrate and the SiGe thin film₂Film, thereby making SGOI.

SiGe of SGOI thus fabricated is SiO₂The presence of the film provides a more relaxed lattice constant in the lateral direction than Si. On the other hand, in SiO₂When the film forming conditions are inappropriate, misalignment may occur. That is, in order to evaluate and manage the crystal quality of SGOI, it is very important to measure the lattice constant of SiGe in the lateral direction with high accuracy.

That is, it is understood that it is extremely important to be able to evaluate X-ray diffraction with respect to a lattice plane perpendicular to the substrate surface, that is, to be able to perform in-plane diffraction measurement.

Further, since the thickness of the SiGe thin film is very thin, about several tens of nm, X-rays are transmitted at a high incident angle, and thus a sufficient diffraction line cannot be obtained.

On the other hand, in the case of in-plane diffraction, since X-rays are made to be almost incident on the substrate surface, there is an advantage that sufficient diffraction lines can be detected and the accuracy of data can be ensured.

When the rocking curve measurement is performed on SiGe (400) as an example of a SiGe lattice plane perpendicular to the substrate surface, the following procedure may be performed.

A substrate (sample S) having an SGOI formed thereon is disposed and fixed on the sample stage 10, and the χ -rotation mechanism 35 is driven to set the substrate substantially perpendicular to a horizontal plane. Since the X-ray cannot be incident when the X-ray is completely parallel to the X-ray incidence direction, the X-ray can be almost closely incident on the substrate by adjusting the drive of the X-ray rotation mechanism 35 or the X ω rotation mechanism 36.

Next, after the X-and Y-moving mechanisms 32 and 33 are driven to determine the measurement points, the measurement points are alignedThe rotation mechanism 31 or the goniometer 20 performs drive adjustment to set the substrate and the X-ray irradiation unit 40 at an angle at which the X-ray bragg-reflects on the Si crystal lattice plane (400).

With this setting, the peak intensity of the diffracted X-rays reflected from the (400) plane of the Si substrate crystal and the diffracted X-rays reflected from the SiGe (400) plane in a direction slightly shifted from this point are detected. The X-ray detector 50 is configured to be able to detect both the diffracted X-rays from the Si substrate crystal and the diffracted X-rays from the SiGe.

The X-ray irradiation unit 40 can irradiate the surface with monochromatic X-rays having a small area condensed at a high resolution, and therefore can irradiate the substrate with X-ray beams in the condensed angle range at a time. Therefore, the rocking curve measurement can be performed in a very short time without scanning the X-ray irradiation unit 40, the X-ray detector 50, the substrate, and the like.

Of course, the rocking curve can be measured by narrowing the divergence angle of the X-ray from the X-ray source by using a beam slit or the like and scanning a goniometer equipped with the X-ray source.

On the other hand, as described above, in the X-ray inspection apparatus of the present embodiment, since the two-dimensional detector is used as the X-ray detector 50, it is not essential to scan the X-ray detector 50 in accordance with the X-ray source. In addition, the measurement point of the sample is used as a rotation center pairThe rotation mechanism 31, the X movement mechanism 32, and the Y movement mechanism 33 can perform the rocking curve measurement by performing the scanning by adjusting the driving.

As described above, the X-ray inspection apparatus according to the present invention can perform the rocking curve measurement in the in-plane diffraction with high accuracy and high speed for the SiGe epitaxial thin film and the like, and can play an extremely important role in the analysis and management of the crystal quality of the thin film.

[ Pole determination ]

Next, the function of pole measurement provided in the X-ray inspection apparatus having the above-described configuration will be described.

In pole measurement, as shown in FIG. 13, focusing on a certain crystal lattice plane of a sample S, 2 parameters, i.e., the elevation angle (Japanese: あおり angle) α and the in-plane rotation angle β of the sample S, are changed, X-rays are made to enter the sample S from various directions, and diffracted X-rays diffracted from the crystal lattice plane are measured. A measurement method in which the intensity distribution of diffracted X-rays is plotted in a pole diagram with α and β as parameters and which α and β positions the diffracted X-rays are observed is analyzed is pole measurement.

By this extreme point measurement, the crystal orientation and orientation of the thin film material, particularly the polycrystalline thin film, can be evaluated.

The control system (control section) shown in fig. 8 includes the following control functions: the positioning mechanism 30, the goniometer 20, and the X-ray irradiation unit 40 are controlled to perform pole measurement.

That is, a control program for performing the pole measurement is installed in advance in the storage unit 110 of the control system (control unit) shown in fig. 8. Further, the storage unit 110 stores setting information necessary for pole measurement as arrangement data. The Central Processing Unit (CPU)100 reads out necessary setting information in accordance with the control program, and outputs the setting information to each component of the control system.

Specifically, the positioning controller 102 drives and controls the χ -rotation mechanism 35 constituting the positioning mechanism 30 to rotate the surface of the sample S disposed in the sample disposition part 11 about the χ -axis, thereby changing the elevation angle α of the pole measurement within the range of 0 ° to 90 °.

The positioning controller 102 also constitutes the positioning mechanism 30The rotation mechanism 31 performs drive control so that the surface of the sample S disposed in the sample arrangement portion 11 is aligned withThe axis is rotated about the center, thereby changing the in-plane rotation angle β measured by the pole.

Thus, the XG controller 101 controls the X-ray irradiation unit 40 fixed at a constant position to irradiate the X-ray a toward the sample S. Then, the count control circuit 104 controls the X-ray detector 50 so that the X-ray detector 50 detects the diffracted X-rays diffracted from the sample at a constant position.

The present invention is not limited to the above-described embodiments, and various other modifications and applications are possible.

For example, the X-ray inspection apparatus according to the above-described embodiment is applied to an inspection target of a semiconductor wafer circulating in a semiconductor production line, but is not limited thereto, and may be applied to an X-ray inspection in which a minute portion of a semiconductor element is used as a measurement site in a subsequent step of the semiconductor production line.

In the above-described embodiments, the functions of the in-plane X-ray diffraction measurement, the rocking curve measurement of the in-plane diffraction, and the pole measurement have been described, but the X-ray inspection apparatus of the present invention is not limited to these measurements, and can of course perform normal X-ray diffraction measurement, rocking curve measurement, X-ray reflectance measurement, reciprocal lattice mapping measurement, and the like.

In the X-ray inspection apparatus shown in fig. 2A and 2B, the X-moving mechanism 32 is provided between the Y-moving mechanism 33 and the χ ω -rotating mechanism 36, but as shown in fig. 14A and 14B, the following configuration may be adopted: an X-moving mechanism 32 is provided under the X-rotating mechanism 35, so that not only the sample stage 10,The rotation mechanism 31, the Z-movement mechanism 34, and the Y-movement mechanism 33 are linearly moved in the X direction, and the χ ω -rotation mechanism 36 and the χ -rotation mechanism 35 are also linearly moved in the X direction.