JP2551728Y2 - Height adjustment dummy for total reflection X-ray fluorescence spectrometer - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention relates to a height adjustment in a total reflection X-ray fluorescence analyzer for irradiating a sample surface with primary X-rays at a small incident angle and analyzing X-ray fluorescence from the surface layer of the sample. It is related to a dummy for use.

[0002]

2. Description of the Related Art Conventionally, a total reflection X-ray fluorescence analyzer has
It is used as a device for analyzing a dry sample obtained by dropping a liquid sample or an impurity attached to a sample surface layer onto a substrate and drying the sample (see, for example, JP-A-63-78056). An example of this type of device is shown in FIG.

In FIG. 3, a primary X-ray B1 emitted from an X-ray source (not shown) is irradiated on the surface of a dried sample 72 at a small incident angle α (for example, about 0.05 ° to 0.10 °). The dried sample 72 is obtained by attaching a liquid sample such as a hydrofluoric acid solution or hydrochloric acid to the surface 71 of the substrate 70 by being dropped and dried, and a glass plate having stable physical properties is used as the substrate 70. In the case of total reflection X-ray fluorescence analysis, the primary X-ray B1 is set to have a small spread in order to increase the efficiency. A part of the incident primary X-ray B1 is totally reflected and becomes a reflected X-ray B2, and another part is a dried sample 7.
2 are excited to generate fluorescent X-rays B3 unique to the elements constituting the dried sample 72. The fluorescent X-ray B3 is incident on the fluorescent X-ray detector 60 arranged to face the dry sample 72. The incident fluorescent X-ray B3 is transmitted to the fluorescent X-ray detector 60.
In the above, after the X-ray intensity is detected, based on the analysis signal a from the fluorescent X-ray detector 60, the multiplex height analyzer 61
As a result, a desired X-ray spectrum is obtained.

In this type of total reflection X-ray fluorescence spectrometer, since the incident angle α of the primary X-ray B1 is very small, reflected X-rays B2 and scattered X-rays are hardly incident on the X-ray fluorescence detector 60.
There is an advantage that noise is smaller than the output level of the fluorescent X-ray B3 detected by the fluorescent X-ray detector 60. That is, a large S / N ratio can be obtained, and therefore, there is an advantage that the analysis accuracy is high and, for example, even a trace amount of impurities can be detected. Also, most of the primary X-rays B1 only reach inside the layer of the dried sample 72, and the substrate 7 below the dried sample 72
Do not enter inside 0. Therefore, the intensity of the fluorescent X-rays B3 from the dried sample 72 having almost no thickness is increased.
This type of liquid is suitable for analyzing a dried sample 72 obtained by drying the liquid.

[0005] Incidentally, although the dried sample 72 adheres to the substrate 70, it is inevitable that the thickness of the substrate 70 varies, so that the surface level of the dried sample 72 is different for each dried sample 72. different. Here, in the total reflection X-ray fluorescence analysis, since the primary X-ray B1 is incident on the surface of the dried sample 72 at a small incident angle α (0.05 ° to 0.10 °), if the thickness changes by Δz, the incident position P Is about 500 to 1000 times Δz. Therefore, the position (incident position P) of the dried sample 72 excited by the primary X-ray B1 having a small spread is largely shifted from the front (directly below) the fluorescent X-ray detector 60. Therefore,
Since the relative intensity of the fluorescent X-ray B3 incident on the fluorescent X-ray detector 60 is significantly reduced and the S / N ratio is also reduced, a large error occurs in the analysis result. If the displacement is large, the incident position P deviates from the field of view of the fluorescent X-ray detector 60, and detection is not possible.

[0006]

Here, in the case of a sample such as a wafer, a displacement Δz in the height direction of the sample is detected by a distance detector, and a sample table on which a wafer is mounted is adjusted in accordance with the displacement Δz. Is moved up and down.
However, the distance detector generally emits infrared rays and detects the reflected light. On the other hand, in the case of the dried sample 72, the distance detection is performed because the substrate 70 is a glass plate that does not reflect the infrared rays. Can not. As a countermeasure, it is conceivable to measure the thickness of the glass plate mechanically. However, since the measurement accuracy is inaccurate, sufficient analysis accuracy cannot be obtained and it is troublesome.

The present invention has been made in view of the above-mentioned conventional problems. When analyzing a sample with a total reflection X-ray fluorescence spectrometer, the surface level of the sample can be detected with a laser type distance detector. It is an object of the present invention to provide an adjustment dummy.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method for manufacturing a semiconductor device, comprising: a pair of upper plates mounted on a surface of a substrate on which a sample is attached; and a material for reflecting light from a distance detector. And a pair of lower plates having an upper surface joined to a lower surface of the upper plate to form a height adjustment dummy, and the height adjustment dummy forms a primary X-ray incidence opening at the center. .

[0009]

According to this invention, since the upper surface of the lower plate is joined to the lower surfaces of a pair of upper plates mounted on the surface of the substrate,
It is at the same level as the surface of the substrate. Therefore, the surface level of the substrate, that is, the surface level of the sample can be measured by detecting the upper surface level of the lower plate made of a material reflecting the light from the distance detector with the distance detector.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, an irradiation device 50 includes an X-ray source 51.
And a parallel optical system 52. The primary X-ray B1 emitted from the X-ray source 51 is converted into a parallel light by the parallel optical system 52, and is incident on the surface of the dry sample 72 at a small incident angle α.
(FIG. 2). Substrate 7 with dry sample 72 attached
0 is placed on the sample stage 40. It should be noted that the thickness t of the substrate 70 shown in FIG.

A distance detector 30 is disposed near the fluorescent X-ray detector 60 shown in FIG. The distance detector 30 and the fluorescent X-ray detector 60 are arranged to face the sample table 40. The distance detector 30 outputs light B4 such as infrared light.
And outputs the detected level Z (FIG. 2) to the control device 31 as a level signal b by detecting the level of the measuring point 20 according to the incident position of the reflected light B5 from the measuring point 20 immediately below. I do. The accuracy of detection by the distance detector 30 is about 1.0 μm.

On the front surface 71 of the substrate 70, a pair of upper plates 2 of the dummy 1 for height adjustment is mounted. The height adjusting dummy 1 is formed by bonding the upper surfaces 5 of a pair of lower plates 4 to the lower surfaces 3 of the upper plates 2 with an adhesive. An entrance aperture 6 for the X-ray B1 is formed. The lower plates 4, 4 are arranged parallel to each other in a direction intersecting with the primary X-ray B1, while the upper plates 2, 2 are arranged substantially parallel to the incident direction of the primary X-ray B1.
The upper plate 2 and the lower plate 4 are made of, for example, a silicon plate, and are made of a material that reflects light B4 emitted from the distance detector 30. Lower surface 3 of upper plate 2 and lower plate 4
Upper surface 5 of is mirror-finished, and finished to about 1.0μmR _max.

As shown in FIG. 2, the sample table 40 is vertically and rotatably mounted on a swivel base 41, and is driven by a driving device M such as a motor. The turning base 41 is horizontally moved on a slide base 42 by a drive motor (not shown).

The control device 31 is composed of, for example, a microcomputer, and receives a level signal b from the distance detector 30 and outputs a drive signal c to a drive device M. Other configurations are the same as those of the conventional example, and the same or corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.

Next, a method for adjusting the level of the sample surface will be described. First, the substrate 70 to which the dried sample 72 of FIG. Then, the substrate 70
Is placed on the lower surface 3 of the upper plate 2 of the height adjusting dummy 1. Thereafter, as shown in this figure, the sample table 40 is set so that one lower plate 4 of the dummy 1 is directly below the distance detector 30.
Is moved in the radial direction r. After this movement, the distance detector 30
Emits light B4 to an arbitrary measurement point 20 on the upper surface 5 of the lower plate 4, measures the level Z (FIG. 2) of the upper surface 5 of the lower plate 4 based on the incident position of the reflected light B5, The signal b is output to the control device 31. Subsequently, the sample table 40 is moved in the radial direction r.
And the level Z of the upper surface 5 of the other lower plate 4 (FIG. 2)
And outputs a level signal b to the control device 31. The control device 31 having received the two level signals b calculates an error ΔZ from the reference level based on the average value, and moves the sample stage 40 of FIG. Up and down. Thereby, the level of the upper surface 5 of the lower plate 4 becomes a predetermined level.

Here, since the upper surface 5 of the lower plate 4 in FIG. 1 is joined to the lower surface 3 of the upper plate 2 placed on the surface 71 of the substrate 70, the upper surface 5 is at the same level as the surface 71 of the substrate 70. is there. Therefore, by setting the level of the upper surface 5 of the lower plate 4 to a predetermined level as described above,
1, that is, the surface level of the dried sample 72 is set to a predetermined level. As a result, the irradiation range A of the primary X-ray B1
(Indicated by a two-dot chain line) is located immediately below the fluorescent X-ray detector 60 in the dried sample 72, so that the relative intensity of the fluorescent X-ray B3 is kept large, so that the analysis accuracy is improved.

Incidentally, the upper surface 5 of the lower plate 4 needs to have a smooth surface with small irregularities. Here, in this embodiment, the height adjustment dummy 1 is formed of a silicon plate, and since the silicon plate is generally used as a material for a wafer having a smooth surface, the production of the height adjustment dummy 1 is not required. Easy.

In addition, since this type of X-ray fluorescence analyzer is often used as an apparatus for analyzing impurities on a wafer, the wafer 1 and the dried sample 72 are formed by forming the height adjusting dummy 1 on a silicon plate. Can be measured by the same distance detector 30.

In the above embodiment, the height adjustment dummy 1 is made of a silicon plate. However, the material of the height adjustment dummy 1 is not limited to silicon. What is necessary is just to be comprised with the material which reflects the light B4 from a light source.

[0020]

As described above, according to the present invention, the lower surface of the pair of upper plates mounted on the surface of the substrate and the lower plate formed of a material reflecting light from the distance detector are provided. Since the dummy for height adjustment is formed by joining the upper surface, the surface level of the sample adhered to the surface of the substrate can be measured by measuring the upper surface level of the lower plate. Therefore, the error at the surface level of the sample becomes smaller,
Analysis accuracy by total reflection X-ray fluorescence is improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a total reflection X-ray fluorescence spectrometer according to an embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a side view showing the principle of general total reflection X-ray fluorescence analysis.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Height adjustment dummy, 2 ... Upper plate, 3 ... Lower surface of upper plate, 4
... lower plate, 5 ... upper surface of the lower plate, 6 ... opening for incidence, 30 ... distance detector, 50 ... irradiation device, 60 ... fluorescent X-ray detector, 70
... substrate, 71 ... substrate surface, 72 ... dry sample, B1 ... primary X-ray, B3 ... fluorescent X-ray, B4 ... light, B5 ... reflected light.

Claims (1)

(57) [Scope of request for utility model registration] An irradiation device for irradiating a primary X-ray to a surface of a sample attached to a surface of a substrate at a small incident angle, and a fluorescent X-ray from a sample facing the sample and receiving the primary X-ray. An X-ray fluorescence detector for detection and a distance detector for detecting a level of a measurement point by reflected light of emitted light are provided, and the X-ray fluorescence is analyzed based on a detection result of the X-ray fluorescence detector. A height adjustment dummy in the total reflection X-ray fluorescence analyzer, and a pair of upper plates mounted on the surface of the substrate;
It is made of a material that reflects light from the distance detector, and is composed of a pair of lower plates whose upper surfaces are joined to the lower surfaces of the upper plates, and has a central X-ray incidence opening formed at the center. Height adjustment dummy in reflection X-ray fluorescence analyzer.