X-ray inspection device

Abstract

The present invention is provided with a sample stage 11 for arranging a sample and a sample stage 10 including a sample stage moving mechanism 12 for moving the sample stage 11, and a goniometer 20 including first and second rotating arms 22 and 23 rotating independently. X-ray irradiation units 20, 30 for irradiating the surface of the sample with X-rays are mounted on the first rotating arm 22. An X-ray detection unit 60 for detecting X-rays diffracted or reflected from the sample is mounted on the second rotating arm 23. The goniometer 20 is further provided with a balancer 28 for adjusting the position of the center of gravity of the goniometer 20, and a center-of-gravity position adjusting mechanism 29 for maintaining the position of the center of gravity of the goniometer 20 adjusted by the balancer 28.

Description

X-ray inspection equipment

[0001] The present invention relates to an X-ray inspection apparatus suitable for the technical field of manufacturing elements having a multilayer structure in which many thin films are stacked on a substrate, such as the semiconductor manufacturing field.

[0002] The characteristics of devices with multilayer structures, such as semiconductors, in which many thin films are stacked on a substrate, change depending on the thickness, density, crystallinity, and other conditions of the thin films that are formed. In recent years, these devices have become increasingly miniaturized and integrated, and this trend has become more pronounced. For this reason, there is a demand for thin film inspection equipment that can accurately measure the condition of the thin films that have been formed.

[0003] Known inspection devices of this type include direct measurement using a cross-sectional transmission electron microscope (TEM), film thickness inspection devices using optical interference or ellipsometry, and photoacoustic devices. Cross-sectional transmission electron microscopes (TEM) cannot be incorporated into the manufacturing process to inspect the thin film being inspected in real time, which is called in-line inspection, and in reality, products extracted from the manufacturing line for inspection are discarded after inspection. Furthermore, film thickness inspection devices using optical interference or ellipsometry and photoacoustic devices are suitable for in-line inspection, but they lack the accuracy to measure thin films of a few nanometers thick.

[0004] For semiconductor device manufacturers, disposable testing wafers (blanket wafers) are a significant cost burden. In particular, as semiconductor wafers have become larger in diameter in recent years, the cost of a single blanket wafer has been rising.

[0005] In view of these circumstances, the present applicant has previously proposed an in-line X-ray thin film inspection device that can be incorporated into the manufacturing process of film-formed products to directly inspect the products themselves, making it possible to inspect even thin films of a few nanometers with sufficient accuracy without disposing of wafers (see Patent Documents 1 and 2).

[0006] Japanese Patent Application Laid-Open No. 2006-153767 International Publication No. WO2019 / 130663

[0007] Furthermore, recent semiconductor devices are becoming faster and more dense (three-dimensional) to realize more advanced products. In particular, cutting-edge transistor structures have evolved from conventional planar field-effect transistors (FETs) to fin-field-effect transistors (Fin-FETs) and are currently evolving to gate-all-around field-effect transistors (GAA-FETs). GAA-FETs are fabricated through a complex manufacturing process that involves repeated deposition of silicon (Si) / silicon germanium (SiGe) multilayer epitaxial thin films, patterning, and removal of the SiGe thin films. At each step, it is extremely important to measure and manage the thickness of the deposited epitaxial thin film and the patterned portion, as well as the film's composition, strain, stress, and crystallinity.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an X-ray inspection apparatus which is a further improvement on the X-ray thin film inspection apparatus previously proposed by the applicant, and which is suitable for application to the QC process (Quality Control Process) in semiconductor manufacturing lines and which is capable of inspecting today's complex and specialized semiconductor devices non-destructively and with high efficiency.

[0009] The X-ray inspection apparatus of the present invention comprises: a sample stage including a sample stage on which a sample is placed and a sample stage moving mechanism for moving the sample stage; a goniometer including first and second rotating arms that rotate independently; an X-ray irradiation unit attached to the first rotating arm that irradiates X-rays onto the surface of the sample placed on the sample stage; and an X-ray detection unit attached to the second rotating arm that detects X-rays diffracted or reflected from the sample; and further comprises: a balancer that adjusts the position of the center of gravity of the goniometer; and a center of gravity position adjustment mechanism that maintains the position of the center of gravity of the goniometer adjusted by the balancer.

[0010] The balancer includes a balance arm that rotates in conjunction with the first rotating arm and a plurality of weight members attached to the balance arm, and the center of gravity position adjustment mechanism can be incorporated into the balance arm and configured to move some of the plurality of weight members.

[0011] The center-of-gravity position adjustment mechanism may be configured to move some of the weight members in response to a change in the moment of force acting on the first rotating arm.

[0012] Furthermore, the center of gravity position adjustment mechanism may include a movable member that moves on the balance arm, a drive source that drives the movable member, and a computer that controls the drive source to move the movable member, with a portion of the weight member attached to the movable member, and the computer may be configured to control the drive source based on the amount of movement of the movable member so that a change in the moment of force acting on the balance arm offsets a change in the moment of force acting on the first pivot arm.

[0013] Furthermore, the X-ray inspection apparatus of the present invention can be configured such that the X-ray irradiation unit is a focused X-ray irradiation unit that irradiates focused X-rays onto a surface of a sample placed on the sample stage, and further includes an irradiation unit movement adjustment mechanism that is incorporated into the first rotating arm and moves the focused X-ray irradiation unit on the first rotating arm.

[0014] Furthermore, the X-ray inspection apparatus of the present invention may also be configured to include a parallel X-ray irradiation unit that irradiates parallel X-rays onto the surface of a sample, and the focused X-ray irradiation unit and the parallel X-ray irradiation unit may be installed side by side on the first rotating arm.

[0015] Here, the irradiation unit movement adjustment mechanism can be configured to include an irradiation unit retraction mechanism that retracts the focused X-ray irradiation unit from the first pivot arm to a position that avoids interference with peripheral members.

[0016] Furthermore, the sample stage moving mechanism includes a guide frame that supports both sides of the sample stage and rotates the sample stage, and is configured to move the guide frame linearly laterally together with the sample stage, and the irradiation unit retraction mechanism can be configured to retract the focused X-ray irradiation unit on the first rotating arm to a position that avoids interference with the guide frame that moves linearly laterally.

[0017] FIG. 2A is a front perspective view showing the appearance of an X-ray inspection apparatus according to an embodiment of the present invention. FIG. 2A is a front view schematically showing the main structure of an X-ray inspection apparatus according to an embodiment of the present invention, and FIG. 2B is a left side view of the same. FIG. 2B is a diagram schematically showing the movement direction of the sample stage by the sample stage movement mechanism. FIG. 2C is a perspective view showing the appearance of a focused X-ray irradiation unit and an irradiation unit movement adjustment mechanism. FIG. 2D is a plan view showing the focused X-ray irradiation unit and the irradiation unit movement adjustment mechanism. FIG. 2E is a perspective view showing the focused X-ray irradiation unit and the irradiation unit movement adjustment mechanism as viewed from the back side. FIG. 2F is a perspective view showing a rotation adjustment mechanism included in the irradiation unit movement adjustment mechanism. FIG. 2G is a perspective view showing a goniometer as viewed from the back side. FIG. 2H is a plan view of an X-ray detection unit. FIG. 2H is a back view of an X-ray detection unit. FIG. 2I is a diagram schematically showing the movement of a slider included in a light-receiving-side optical component automatic selection mechanism.

[0018] P: measurement point, 10: sample stage, 11: sample stage, 12: sample stage moving mechanism, 12a: cradle, 20: goniometer, 21: goniometer body, 22: first rotating arm, 23: second rotating arm, 24: balancer, 25: balance arm, 26, 26a: weight member, 27: drive shaft, 28: balancer, 28a: balance arm, 28b: weight member, 29: center of gravity position adjusting mechanism, 291: guide rail, 292: moving member, 293: drive motor, 294: ball screw, 30: focused X-ray irradiation unit, 40: parallel X-ray irradiation unit, 50: irradiation unit movement adjusting mechanism, 51: irradiation unit retraction mechanism, 511: guide rail, 512: slider, 513: drive motor, 514: ball screw, 52: Vertical axis direction moving mechanism, 521: Base, 522: Guide, 523: Sliding member, 524: Drive motor, 525: Transmission mechanism, 526: Support member, 53: Rotation adjustment mechanism, 531: Rotation shaft, 532: Rotation lever, 533: Spring member, 534: Fixed block, 535: Operation screw (drive unit), 536: Fastening member, 60: X-ray detection unit, 61: Two-dimensional X-ray detector, 62: Parallel Soller slit (light-receiving side optical component), 63: Vertical Soller slit (light-receiving side optical component), 64: Light-receiving slit (light-receiving side optical component), 65: Analyzer (light-receiving side optical component), 70: Light receiving side optical component selection mechanism, 71: Support plate, 72a, 72b: Guide rails, 73a: First slider, 73b: Second slider, 73c: Third slider, 73d: Fourth slider, 74: Drive motor, 75: Ball screw, 100: Optical microscope

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray inspection apparatus according to an embodiment of the present invention is incorporated into a semiconductor manufacturing line and has a function of non-destructively inspecting semiconductor wafers (samples) using X-rays.

[0020] [Outline of X-ray inspection apparatus] Fig. 1 is a front perspective view showing the appearance of an X-ray inspection apparatus according to an embodiment of the present invention, Fig. 2A is a front view schematically showing the main structure of the apparatus, and Fig. 2B is a left side view of the same. As shown in these figures, the X-ray inspection apparatus according to this embodiment includes the following components: a sample stage 10, a goniometer 20, two X-ray irradiation units 30 and 40, and an X-ray detection unit 60.

[0021] The sample stage 10 incorporates a sample stage 11 for placing a sample thereon and a sample stage moving mechanism 12 for moving the sample stage 11. A semiconductor wafer serving as the sample is placed and fixed on the upper surface of the sample stage 11. The sample stage moving mechanism 12 drives the sample stage 11 to position a measurement site that has been set in advance on the surface of the sample at a measurement point P that has been set in advance in the apparatus. X-rays are then irradiated onto the measurement point P from the X-ray irradiation unit 30 or 40, and the X-rays diffracted or reflected from the surface of the sample are detected by the X-ray detection unit 60.

[0022] The X-ray inspection system incorporates a computer (not shown), which analyzes various characteristics of the sample based on the X-ray detection data output from the X-ray detection unit. The computer also automatically controls the operation of each component of the X-ray inspection system. An inspection program and a control program for executing these functions are pre-installed in the computer.

[0023] FIG. 3 is a schematic diagram showing the movement direction of the sample stage by the sample stage moving mechanism. As shown in the figure, the sample stage moving mechanism 12 has the functions of linearly moving the sample stage 11 in the X, Y, and Z directions and rotating it in the φ direction around the φ axis. Furthermore, the sample stage moving mechanism 12 has the functions of swinging the sample stage 11 around the χ axis in the forward and reverse directions indicated by the arrow χ and swinging the sample stage 11 around the χω axis in the forward and reverse directions indicated by the arrow χω. Here, the X and Y directions are two orthogonal directions on a plane parallel to the top surface of the sample stage 11 (i.e., the surface of the sample placed on the sample stage 11), and the Z direction is a direction perpendicular to the top surface of the sample stage 11. The φ axis is a rotation axis that passes through the measurement point P and is perpendicular to the top surface of the sample stage 11. The χ axis is a horizontal axis that intersects at right angles with the rotation axis of the goniometer 20 (described later) at the measurement point P. The χω axis is a horizontal axis that intersects at right angles with the χ axis at the measurement point P.

[0024] Returning to Figures 1, 2A, and 2B, the goniometer 20 includes first and second rotating arms 22 and 23, and a θs rotation mechanism and a θd rotation mechanism (neither of which is shown) are built into the goniometer body 21. The first rotating arm 22 is connected to the drive shaft of the θs rotation mechanism and driven by the same rotation mechanism. The second rotating arm 23 is connected to the drive shaft of the θd rotation mechanism and driven by the same rotation mechanism. The θs rotation mechanism rotates the first rotating arm 22 in the forward and reverse directions indicated by the arrow θs around the θs axis, which passes through a preset measurement point P and extends horizontally (see Figures 2A and 3). Two X-ray irradiation units 30 and 40 are attached to the first rotating arm 22. By rotating the first rotating arm 22, the angle of incidence of the X-rays emitted from either the X-ray irradiation unit 30 or 40 with respect to the surface of the sample is set.

[0025] The θd rotation mechanism rotates the second rotation arm 23 in the forward and reverse directions of the arrow θd around the θd axis, which passes through a preset measurement point P and extends horizontally (see FIGS. 2A and 3). The X-ray detection unit 60 is attached to the second rotation arm 23. The scanning angle of the X-ray detection unit 60 is set by moving the second rotation arm 23. That is, by moving the second rotation arm 23, the X-ray detection unit 60 is positioned to detect X-rays diffracted or reflected from the surface of the sample. In this way, the first rotation arm 22 and the second rotation arm 23 are independently rotated by the drive of the θs rotation mechanism and the θd rotation mechanism, respectively. The θs axis and the θd axis described above are coaxial rotation centers.

[0026] 1, the component designated by the reference numeral 100 is an optical microscope, which has the function of observing a thin film pattern formed on the surface of a semiconductor wafer (sample) placed on a sample stage and recognizing the position of a measurement site that has been set in advance in the area where the thin film pattern is formed. The measurement site whose position has been recognized by this optical microscope is moved to a measurement point P by a sample stage moving mechanism 12, and X-ray inspection is performed. When X-ray inspection is performed, the optical microscope is retracted from above the semiconductor wafer (sample) by a moving mechanism (not shown).

[0027] 1, the X-ray inspection apparatus according to this embodiment has two X-ray irradiation units 30, 40 mounted one above the other on the first rotary arm 22. One of these X-ray irradiation units 30, 40 is a focused X-ray irradiation unit 30 that irradiates the surface of a sample with focused X-rays, and the other is a parallel X-ray irradiation unit 40 that irradiates the surface of a sample with parallel X-rays.

[0028] Although not shown, the focused X-ray irradiation unit 30 includes an X-ray source incorporating a microfocus X-ray tube and a hybrid monochromator composed of a curved crystal and a multilayer mirror, and has the function of converting the X-rays emitted from the X-ray source into monochromatic X-rays with a specific wavelength by the hybrid monochromator and focusing the X-rays at one location. The focused X-ray irradiation unit 30 can converge X-rays to a microfocus of, for example, about 50 μm and irradiate the surface of the sample, making it suitable for X-ray inspection of microscopic areas on the surface of a sample, such as a fine pattern film formed on a semiconductor wafer.

[0029] On the other hand, the parallel X-ray irradiation unit 40 includes an X-ray source with a built-in rotating anticathode and a monochromator (not shown), and has the function of converting the parallel X-rays emitted from the X-ray source into characteristic X-rays of a specific wavelength by the monochromator and irradiating the surface of the sample with the monochromated X-rays. The parallel X-ray irradiation unit 40 can irradiate a wide area on the surface of the sample with X-rays, thereby enabling high-speed and high-resolution X-ray inspection of, for example, a thin epitaxial layer (blanket film) formed on a semiconductor wafer.

[0030] The X-ray inspection apparatus of this embodiment has these two types of X-ray irradiation units 30, 40 attached to the first rotating arm 22, and by selecting and using either the X-ray irradiation unit 30 or 40 depending on the content of the X-ray inspection, various X-ray inspections can be performed in each process of the semiconductor manufacturing line, such as the film thickness of the thin epitaxial layer formed and the formed pattern portion, as well as the composition, strain / stress, crystallinity, etc. Therefore, for the purpose of performing non-destructive and highly efficient X-ray inspection of today's complex and specialized semiconductor devices, this apparatus is suitable for application to the QC process in the semiconductor manufacturing line.

[0031] Next, the X-ray detection unit 60 attached to the second rotating arm 23 includes a two-dimensional X-ray detector 61. The two-dimensional X-ray detector 61 has a two-dimensional planar X-ray detection section, and can collectively record X-rays diffracted or reflected from the surface of the sample on this planar X-ray detection section. Therefore, compared to one-dimensional X-ray detectors such as proportional counters (PCs) and scintillation counters (SCs), the two-dimensional X-ray detector 61 has the advantage of being able to shorten the time required for measurement.

[0032] In recent years, two-dimensional semiconductor detectors have also been developed that have an X-ray detection section that has an array of many silicon semiconductor elements with extremely small pixel sizes of 100 μm or less, and that can detect X-rays with high precision in a short time with high position resolution using these semiconductor elements. By employing this type of two-dimensional semiconductor detector in the X-ray detection unit 60, it becomes possible to achieve highly efficient and highly precise X-ray inspection in semiconductor manufacturing lines.

[0033] 1, the X-ray detection unit 60 includes a plurality of light-receiving side optical components such as solar slits 62 and 63, a light-receiving slit 64, and an analyzer 65, and is also provided with an automatic light-receiving side optical component selection mechanism 70 for selecting and using the plurality of light-receiving side optical components. The plurality of light-receiving side optical components 62 to 65 and the automatic light-receiving side optical component selection mechanism 70 will be described in detail later in sections.

[0034] [Movement adjustment mechanism of focused X-ray irradiation unit (irradiation unit movement adjustment mechanism)] Fig. 4 is a perspective view showing the appearance of the focused X-ray irradiation unit and the irradiation unit movement adjustment mechanism, Fig. 5 is a plan view of the same, Fig. 6 is a perspective view of the same as seen from the back side, and Fig. 7 is a perspective view showing a rotation adjustment mechanism included in the irradiation unit movement adjustment mechanism.

[0035] The focused X-ray irradiation unit 30 needs to position the focus C (see FIG. 4) of the X-rays converged by the hybrid monochromator at a preset measurement point P (see FIGS. 2A and 3) of the device. Therefore, the X-ray inspection device of this embodiment is configured so that an irradiation unit movement adjustment mechanism 50 is incorporated into the first rotating arm 22, and this irradiation unit movement adjustment mechanism 50 can move the focused X-ray irradiation unit 30 on the first rotating arm 22 to adjust the focus position of the irradiated X-rays.

[0036] Specifically, as shown in FIGS. 4 to 6 , the irradiation unit movement adjustment mechanism 50 includes an irradiation unit retraction mechanism 51 that moves the focused X-ray irradiation unit 30 in the longitudinal direction relative to the first rotating arm 22, a vertical axis direction movement mechanism 52 that moves the focused X-ray irradiation unit 30 in the vertical axis direction perpendicular to the longitudinal direction within the rotation plane of the first rotating arm 22, and a rotation adjustment mechanism 53 that rotates the focused X-ray irradiation unit 30 around a rotation axis that is arranged in the same direction as the vertical axis to change the direction of X-ray irradiation.

[0037] 5 , the irradiation unit retraction mechanism 51 includes a guide rail 511 extending in the longitudinal direction of the first rotating arm 22 (in the radial direction about the θs axis), a slider 512 sliding on the guide rail 511, a drive motor (drive source) 513, and a ball screw 514 transmitting the drive force from the drive motor 513 to the slider 512. The slider 512 slides on the guide rail 511 in the longitudinal direction by the drive force of the drive motor 513.

[0038] The vertical axis direction moving mechanism 52 is attached to the slider 512 of the irradiation unit retraction mechanism 51 and moves in the longitudinal direction together with the slider 512. As shown in Fig. 6, the vertical axis direction moving mechanism 52 includes a base 521, a guide 522 extending in the vertical axis direction and provided on a side surface of the base 521, a sliding member 523 sliding along the guide 522, a drive motor (drive source) 524, and a transmission mechanism 525 transmitting the driving force from the drive motor 524 to the sliding member. The sliding member 523 slides in the vertical axis direction along the guide 522 by the driving force of the drive motor 524.

[0039] A support member 526 is fixed to the side surface of the sliding member 523, and as shown in Fig. 6, the focused X-ray irradiation unit 30 is attached to this support member 526 via a rotation adjustment mechanism 53. The rotation adjustment mechanism 53 includes a rotation shaft 531 arranged in the same direction as the vertical axis, a rotation lever 532 attached to one end of the rotation shaft 531, a spring member (biasing member) 533 that biases the rotation lever 532 in one rotation direction, a fixing block 534 for fixing the rotation lever 532 biased by the spring member 533, and an operating screw 535 (drive unit) for finely adjusting the fixed position of the rotation lever 532. The focused X-ray irradiation unit 30 is attached to the other end of the rotation shaft 531, and rotates integrally with the rotation shaft 531 as the rotation lever 532 is rotated.

[0040] The rotating lever 532 is fastened and fixed to the fixed block 534 by a fastening member 536 such as a nut. To rotate the rotating lever 532 and fine-tune the orientation of the focused X-ray irradiation unit 30, the fastening member 536 is loosened, and with the rotating lever 532 abutting against the tip of the operating screw 535, the operating screw 535 is rotated to move the tip in the axial direction. As the tip of the operating screw 535 moves, the rotating lever 532 rotates, and at the desired rotation position, the fastening member 536 is again used to fasten the rotating lever 532 to the fixed block 534 and fix it. This adjustment is performed manually, but because fine adjustment is possible with a simple operation of simply rotating the operating screw 535, the focal point of the X-rays can be positioned at the measurement point P of the device without requiring any skill.

[0041] In this embodiment, the drive unit for fine-tuning the fixed position of the rotating lever 532 is configured with an operating screw 535, and the operating screw 535 is operated manually, but the drive unit can also be configured with a drive source such as a drive motor, and the drive source can be controlled to fine-tune the fixed position of the rotating lever 532.

[0042] The focused X-ray irradiation unit 30 focuses X-rays using a hybrid monochromator, but the distance to the focusing point is shorter than the length of the first rotating arm 22. Therefore, the focused X-ray irradiation unit 30 needs to be positioned close to the measurement point P. However, if the focused X-ray irradiation unit 30 is fixed to the first rotating arm 22 at a position close to the measurement point P, there is a risk that the sample stage 10 (specifically, the sample stage 11 or components of the sample stage moving mechanism 12) will interfere with the focused X-ray irradiation unit 30 when the sample stage 11 is moved by the sample stage moving mechanism 12. In particular, as shown in FIGS. 2A and 2B , the X-ray inspection apparatus according to this embodiment has a guide frame called a cradle 12a that supports both sides of the sample stage 11 to rotate the sample stage 11 in the chi direction. The sample stage 11 slides on a curved surface formed on the cradle 12a and swings in the forward and reverse directions of the chi direction. The cradle 12a moves linearly in the X direction together with the sample stage 11. Therefore, when the focused X-ray irradiation unit 30 is placed near the measurement point P and the cradle 12a is moved linearly in the X direction together with the sample stage 11, the X-ray source at the base of the focused X-ray irradiation unit 30 may interfere with the cradle 12a.

[0043] Therefore, the X-ray inspection apparatus of this embodiment is provided with a function (irradiation unit retraction mechanism) for retracting the focused X-ray irradiation unit 30 to the side of the sample stage 10 when the focused X-ray irradiation unit 30 is not in use (i.e., when the parallel X-ray irradiation unit 40 is used). Specifically, the configuration is such that the focused X-ray irradiation unit 30 can be retracted to the side of the sample stage 10 and interference with the sample stage 10 can be avoided by driving the irradiation unit retraction mechanism 51 to move the focused X-ray irradiation unit 30 close to the tip of the first rotating arm 22 (the opposite side of the θs axis). For this reason, the guide rail 511 of the irradiation unit retraction mechanism 51 is extended to close to the tip of the first rotating arm 22.

[0044] The irradiation unit movement adjustment mechanism 50 is not limited to the above-described configuration, and may be any mechanism that can move the focused X-ray irradiation unit 30 on the first rotating arm 22. Furthermore, the direction in which the focused X-ray irradiation unit 30 is moved by the irradiation unit movement adjustment mechanism 50 is not limited to the above-described direction, and the movement direction can be set arbitrarily as needed.

[0045] The irradiation unit movement adjustment mechanism 50 can also be applied to a goniometer 20 having a configuration in which only the focused X-ray irradiation unit 30 is attached to the first rotating arm 22 .

[0046] 8 is a perspective view of the goniometer as seen from the rear side. The goniometer 20 is equipped with a balancer 24 for balancing the force moments of the X-ray irradiation units 30, 40 attached to the first rotary arm 22 and adjusting the center of gravity of the goniometer 20 to a balanced position.

[0047] The balancer 24 includes a balance arm 25 and a plurality of weight members 26 attached to the balance arm 25 , and is provided on the back side of the goniometer 20 .

[0048] The balance arm 25 is connected to a drive shaft 27 (see FIG. 8) of the θs rotation mechanism that drives the first rotation arm 22, and rotates in conjunction with the first rotation arm 22. The balance arm 25 is disposed on the back side of the goniometer body 21, and extends in a radial direction symmetrical to the first rotation arm 22 about the θs axis.

[0049] When assembling the X-ray inspection device according to this embodiment, the number of weight members 26 attached to the balance arm 25 is adjusted so that the force moment due to the weight members 26 is balanced with the force moments due to the X-ray irradiation units 30, 40 attached to the first pivot arm 22, and the center of gravity of the goniometer 20 is adjusted to a stable position without deviation.

[0050] In order to balance the moment of force due to the X-ray detection unit 60 attached to the second rotating arm 23 and adjust the center of gravity of the goniometer 20 to a balanced position, a balancer 28 is also provided on the back side of the goniometer 20 for the second rotating arm 23. This balancer 28 also includes a balance arm 28a and a plurality of weight members 28b attached to this balance arm 28a (see FIG. 8). However, the following description will be directed to the balancer 24 connected to the first rotating arm 22.

[0051] Furthermore, the X-ray inspection apparatus according to this embodiment is provided with a center-of-gravity position adjustment mechanism 29 for maintaining the center of gravity of the goniometer 20 adjusted by the balancer 24. The center-of-gravity position adjustment mechanism 29 is incorporated into the balance arm 25, and is configured to move a part (26a in FIG. 8) of the weight member 26 attached to the balance arm 25 in a direction toward or away from the θs axis of the goniometer 20.

[0052] 8, the center-of-gravity position adjustment mechanism 29 includes a guide rail 291 extending in the longitudinal direction of the balance arm 25 (in the radial direction about the θs axis), a movable member 292 that moves along the guide rail 291, a drive motor (drive source) 293, and a ball screw 294 that transmits the driving force from the drive motor 293 to the movable member 292. The movable member 292 moves in the longitudinal direction along the guide rail 291 by the driving force of the drive motor 293. One or more weight members 26a are attached to the movable member 292, and the weight members 26a move integrally with the movable member 292 in the longitudinal direction of the balance arm 25. As the weight members 26a attached to the movable member 292 move, the moment of force acting on the balance arm 25 varies.

[0053] The drive motor 293 is controlled by a computer (not shown), and operates in response to changes in the moment of force acting on the first rotating arm 22 to move the moving member 292 .

[0054] As described above, the first rotating arm 22 incorporates an irradiation unit movement adjustment mechanism 50 that moves the focused X-ray irradiation unit 30. The irradiation unit retraction mechanism 51 moves the focused X-ray irradiation unit 30 in a direction approaching the measurement point P when in use, and moves it closer to the tip of the first rotating arm 22 when not in use, thereby avoiding interference with the sample stage 10. In this way, each time the focused X-ray irradiation unit 30 moves on the first rotating arm 22, the moment of force acting on the first rotating arm 22 changes, and the position of the center of gravity of the goniometer 20 also fluctuates.

[0055] Therefore, a computer (not shown) operates the drive motor 293 in response to changes in the moment of force acting on the first rotating arm 22, thereby moving the weight member 26a attached to the moving member 292. As the weight member 26a attached to the moving member 292 moves, the moment of force acting on the balance arm 25 changes.

[0056] The computer controls the drive motor 293 based on the amount of movement of the movable member 292 so that the change in the moment of the force acting on the balance arm 25 cancels out the change in the moment of the force acting on the first rotating arm 22. Specifically, the computer calculates the amount and direction of movement of the movable member 292, and controls the drive motor 293 based on the calculated data. This allows the center of gravity of the goniometer 20 to be maintained in its original, stable position without any deviation.

[0057] Alternatively, a sensor (e.g., a torque sensor) that detects fluctuations in the center of gravity of the goniometer 20 may be installed in the goniometer 20, and the computer may control the drive motor 293 based on the detection signal from the sensor so that the center of gravity of the goniometer 20 returns to its original, stable position without any deviation.

[0058] Furthermore, the center of gravity position adjustment mechanism is not limited to the above-described configuration, and any mechanism having the function of avoiding fluctuations in the center of gravity position of the goniometer 20 adjusted by the balancer 24 may be used.

[0059] [Light-receiving-side optical components of the X-ray detection unit and automatic selection mechanism for the same] Figure 9 is a plan view of the X-ray detection unit, and Figure 10 is a rear view of the same. As described above, the X-ray detection unit 60 includes a two-dimensional X-ray detector 61, a plurality of light-receiving-side optical components 62 to 65, and an automatic light-receiving-side optical component selection mechanism 70. The automatic light-receiving-side optical component selection mechanism 70 has the function of selecting and placing one of the light-receiving-side optical components 62 to 65 in a position in front of the two-dimensional X-ray detector 61 on the trajectory of X-rays diffracted or reflected from the sample.

[0060] 9 and 10, the light-receiving-side optical component automatic selection mechanism 70 is configured by arranging a support plate 71 fixed to the second rotating arm 23 in a position in front of the two-dimensional X-ray detector 61, and incorporating guide rails 72a, 72b, sliders 73a to 73d, a drive motor (drive source) 74, and a ball screw 75 into the support plate 71. That is, as shown in Fig. 9, two pairs of guide rails 72a, 72b extending laterally are arranged front to back on the surface of the support plate 71, and two sliders 73a to 73d (four in total) are slidably engaged with each pair of guide rails 72a, 72b.

[0061] The sliders 73a to 73d move independently, as shown schematically in Fig. 11. The first slider 73a moves along a guide rail 72 installed close to the two-dimensional X-ray detector 61 between a use position in front of the two-dimensional X-ray detector 61 (in front of the light-receiving surface) and a retracted position off to one side. The second slider 73b moves along a guide rail 72 also installed close to the two-dimensional X-ray detector 61 between a use position in front of the two-dimensional X-ray detector 61 (in front of the light-receiving surface) and a retracted position off to the other side. The third slider 73c moves along a guide rail 72 installed farther from the two-dimensional X-ray detector 61 between a use position in front of the two-dimensional X-ray detector 61 (in front of the light-receiving surface) and a retracted position off to one side. The fourth slider 73d moves along a guide rail 72, which is also installed at a position far from the two-dimensional X-ray detector 61, between an operating position in front of the two-dimensional X-ray detector 61 (in front of the light-receiving surface) and a retracted position located to the other side.

[0062] 10, four drive motors 74 and four ball screws 75 that transmit the drive force from each drive motor 74 to each slider 73a to 73d are provided on the back surface of the support plate 71. Each slider 73a to 73d is independently driven by a respective drive motor 74. Note that instead of the ball screws 75 and drive motors 74, linear servo motors can also be used to drive the sliders 73a to 73d.

[0063] Different types of light-receiving-side optical components 62 to 65 are installed on the sliders 73a to 73d, respectively. In this embodiment, the first slider 73a is equipped with a parallel Soller slit 62 as the light-receiving-side optical component, which allows only horizontal X-rays to pass. The second slider 73b is equipped with a vertical Soller slit 63 as the light-receiving-side optical component, which allows only vertical X-rays to pass. The third slider 73c is equipped with a light-receiving-side optical component, which is a light-receiving slit 64 that limits the passing width of X-rays. Finally, the fourth slider 73d is equipped with an analyzer 65 as the light-receiving-side optical component, which allows only X-rays of a specific wavelength to enter the two-dimensional X-ray detector 61.

[0064] Of these light-receiving side optical components 62 to 65, the analyzer 65 is used alone, and at that time the other light-receiving side optical components are moved to their respective retracted positions. Similarly, when the light-receiving slit 64 or any of the Soller slits 62 or 63 is used alone, the other light-receiving side optical components are moved to their respective retracted positions. On the other hand, any of the Soller slits 62 or 63 and the light-receiving slit 64 can be used together. In that case, the Soller slit 62 or 63 and the light-receiving slit 64 are arranged in front and behind each other in their use positions, and the other light-receiving side optical components are moved to their respective retracted positions. Alternatively, all of the light-receiving side optical components 62 to 65 can be moved to their retracted positions, and X-rays diffracted or reflected from the sample can be directly incident on the two-dimensional X-ray detector 61.

[0065] The positioning of each receiving optical component can be performed automatically by controlling the drive motor 74 with a computer. When the X-ray inspection apparatus of this embodiment is incorporated into a semiconductor production line, the positioning of the receiving optical components cannot be performed by an operator in order to maintain a clean ambient environment of the semiconductor production line. However, by using the above-described automatic receiving optical component selection mechanism 70, it is possible to automatically position the desired receiving optical component in front of the two-dimensional X-ray detector 61 while maintaining a clean ambient environment of the semiconductor production line.

[0066] The automatic light-receiving optical component selection mechanism is not limited to the configuration described above, but may be any mechanism that has the function of automatically positioning multiple (not limited to four) light-receiving optical components in positions in front of the two-dimensional X-ray detector 61 and automatically retracting each of them from those positions.

[0067] The light-receiving side optical components that are automatically positioned in front of the two-dimensional X-ray detector 61 by the light-receiving side optical component automatic selection mechanism are not limited to the light-receiving slit 64, the analyzer 65, and the Soller slits 62 and 63, and various optical components suitable for X-ray detection can be set in the required number as needed.

[0068] In the above embodiment, a drive motor is used as the drive source for each mechanism, but this is not limited to this, and various known drive sources such as an air cylinder, a hydraulic cylinder, or a solenoid can be applied to each mechanism.

[0069] Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and applications are possible without departing from the scope of the present invention. For example, the X-ray inspection apparatus of the above-described embodiments is intended to inspect semiconductor wafers flowing through a semiconductor manufacturing line, but is not limited to this, and can also be applied to, for example, X-ray inspection in which a minute portion of a semiconductor element is used as the measurement portion in a post-process of the semiconductor manufacturing line.

[0070] Furthermore, the automatic center of gravity position adjusting mechanism and the automatic light-receiving optical component selecting mechanism can also be applied to a goniometer having only a focused X-ray irradiation unit attached to the first rotating arm, if necessary.

Claims

1. An X-ray inspection device comprising: a sample stage including a sample stage on which a sample is placed and a sample stage movement mechanism for moving the sample stage; a goniometer including first and second rotating arms that rotate independently; an X-ray irradiation unit attached to the first rotating arm that irradiates X-rays onto the surface of the sample placed on the sample stage; and an X-ray detection unit attached to the second rotating arm that detects X-rays diffracted or reflected from the sample; and further comprising: a balancer that adjusts the position of the center of gravity of the goniometer; and a center of gravity position adjustment mechanism that maintains the position of the center of gravity of the goniometer adjusted by the balancer.

2. The X-ray inspection device according to claim 1, characterized in that the balancer includes a balance arm that rotates in conjunction with the first rotating arm and a plurality of weight members attached to the balance arm, and the center of gravity position adjustment mechanism is incorporated into the balance arm and is configured to move some of the plurality of weight members.

3. An X-ray inspection device as described in claim 2, characterized in that the center of gravity position adjustment mechanism is configured to move some of the multiple weight members in response to changes in the moment of force acting on the first rotating arm.

4. The X-ray inspection device described in claim 3, characterized in that the center of gravity position adjustment mechanism includes a moving member that moves on the balance arm, a drive source that drives the moving member, and a computer that controls the drive source to move the moving member, a part of the weight member is attached to the moving member, and the computer is configured to control the drive source based on the amount of movement of the moving member so that changes in the moment of force acting on the balance arm cancel out changes in the moment of force acting on the first pivot arm.

5. An X-ray inspection device according to any one of claims 1 to 4, characterized in that the X-ray irradiation unit is a focused X-ray irradiation unit that irradiates the surface of a sample placed on the sample stage with focused X-rays, and further comprises an irradiation unit movement adjustment mechanism that is incorporated into the first rotating arm and moves the focused X-ray irradiation unit on the first rotating arm.

6. An X-ray inspection device according to claim 5, further comprising a parallel X-ray irradiation unit that irradiates the surface of the sample with parallel X-rays, and wherein the focused X-ray irradiation unit and the parallel X-ray irradiation unit are arranged side by side on the first rotating arm.

7. An X-ray inspection device as described in claim 5, characterized in that the irradiation unit movement adjustment mechanism includes an irradiation unit retraction mechanism that retracts the focused X-ray irradiation unit from the first rotating arm to a position that avoids interference with surrounding components.

8. The X-ray inspection device according to claim 7, characterized in that the sample stage moving mechanism includes a guide frame that supports both sides of the sample stage and rotates the sample stage, and is configured to move the guide frame linearly laterally together with the sample stage, and the irradiation unit retraction mechanism is configured to retract the focused X-ray irradiation unit on the first rotating arm to a position that avoids interference with the guide frame that moves linearly laterally.

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