JPH02272350A - Surface analyzer - Google Patents

Abstract

PURPOSE:To obtain two-dimensional distribution images of plural elements with a relatively simple control sequence by switching an analysis condition to the analysis condition adapted to detection of each element at each time of rotating a table in a surface analyzer provided with an r-theta driving mechanism. CONSTITUTION:A table 6 is continuously rotated in one direction by the number of times corresponding to a number (n) of elements which is preliminarily set by a setting part 20. Each time the table 6 is rotated once, detection data of respective elements existing in the circumferential direction in an analysis object area are individually stored in the storage area of a memory 24. Data stored in the memory 24 is read out on demand to display the two-dimensional distribution image of each element (or coupling state) on a display device 38.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field
It relates to surface analysis devices such as electron spectroscopy.

(b) Conventional technology In surface analysis devices such as XPS, a sample is irradiated with soft X-rays emitted from an X-ray gun, and photoelectrons excited and emitted from the sample surface are separated in energy by an energy analyzer. By detecting this with a detector, elemental analysis and state analysis of the sample is performed. In such cases, it may be desirable to observe a two-dimensional distribution image of the elements or bonding states contained in the sample. However, since XPS uses soft X-rays as an excitation source, it cannot scan the sample surface like an electron beam. Therefore, it is necessary to move the table side on which the sample is placed while keeping the soft X-ray irradiation position fixed.

By the way, conventionally, as a moving mechanism for a table for placing a sample, there is an X-Y drive mechanism that moves the table in X-axis and Y-axis directions that are orthogonal to each other. When using this X-Y drive mechanism, the sample placed on the table can be analyzed over a predetermined area (Xxy%, where X%, Y is each length along the X-axis and Y-axis directions of the sample). In order to
y) Required.

As a result, the vacuum chamber in which the table is placed also requires a large volume to move the table, resulting in the problem of increasing the size of the entire apparatus.

Therefore, in the prior art, a -θ drive mechanism is provided. As shown in FIG. 4, this r-θ drive mechanism allows the table T to rotate along the circumferential direction (θ direction) and
It is provided movably along the radial direction (r direction). In order to observe the entire area of a circular sample (radius r) placed on the table T using this r-θ drive mechanism, the table only needs to move a distance of 3 rX 2 r, and therefore the XY drive Since the entire area of the sample can be analyzed by reducing the distance traveled by the table compared to a conventional mechanism, the volume of the vacuum chamber is also reduced, which has the advantage that the entire apparatus can be made more compact.

By the way, in order to obtain a two-dimensional distribution image of elements or bonding states contained in a sample in an XPS having such an r-θ drive mechanism, conventionally, a microcomputer or the like is used to perform the following operation procedure. It is being done. First, (i) after setting the analyzer voltage to a value suitable for detecting one specific element (or bonding state), as shown in Figure 5, the analysis starting point (r+, θ1) is set to the soft X-ray Move the table T to the irradiation position. (ii
) Then, data is sequentially collected while rotating the table by a predetermined angle θ from this position. (iii) When data collection is completed over a predetermined angle θ, the table is then reversely rotated by θ to return to the original position (r+, θI), and then shifted in the radial direction by 61 minutes. . (iv) Then, the table is rotated again by a predetermined angle θ from this position (r+−Δr, θ,) and data is sequentially collected. Hereinafter, (iii) to (1v) are repeated. Then, a preset analysis target area (symbol ABC in FIG.
Once data has been collected over the entire area (region denoted by After returning to the analysis starting point (r+, θ,), the above procedure is repeated to collect data.

This operation is repeated for as many elements (or bond states) as necessary.

In this way, conventionally, the analyzer voltage was fixed at a value corresponding to one element (or bonding state) until data for the entire region ABCD necessary to display a two-dimensional distribution image was collected. There is even.

(c) Problems to be Solved by the Invention However, in such a conventional analysis method, it is necessary to constantly rotate the table T back and forth by a predetermined angle θ.
Moreover, it is necessary to return the table to the analysis starting point (r+, θυ) every time the measurement of each element (or bond state) is completed.Furthermore, when the table is moved back and forth, a mechanical backing such as a gear is required. This has to be removed because of the rush effect, which complicates the control sequence for table movement.

(d) Means for Solving the Problems The present invention has been made in view of the above circumstances, and uses a relatively simple control sequence to two-dimensionally control a plurality of elements (or bonding states). This allows a distribution image to be obtained.

Therefore, in the present invention, a surface analysis device equipped with a −θ drive mechanism in which a table on which a sample is placed is rotatable in the circumferential direction and movable in the radial direction has the following configuration. .

That is, in the surface analysis device of the present invention, the number of elements to be analyzed (or bonding states), analysis conditions adapted to detect each element (or bonding state), and settings for setting the regions to be analyzed. a rotation control unit that outputs a control signal to continuously rotate the table in one direction a number of times corresponding to the number of elements (or bond states) set in this setting unit, and an analysis target set in the setting unit. An analysis condition control section that outputs a control signal to switch to analysis conditions suitable for detection of each element (or bond state) each time the table is rotated across the region; )
a movement control section that outputs a control signal to move the table a predetermined distance in the radial direction when the table is rotated a number of times corresponding to the number of times; , and storage means for storing detection data of elements (or bond states) obtained from within the analysis target region in separate storage areas.

(e) If you want to obtain a two-dimensional distribution image of the elements (or bonding states) to be analyzed, first set the number of elements (or bonding states) and the number of elements (or bonding states) of each element (or bonding state) using the setting section.
Analysis conditions and analysis target area suitable for detecting are set in advance.

When analysis starts, the rotation control section continuously rotates the table in one direction the number of times corresponding to the number of elements (or bond states) set in the setting section, while the analysis condition control section Each time the table is rotated over the area to be analyzed, the analysis conditions are changed to suit the detection of each element (or bond state). Therefore, detection data of one specific element (or bonding state) present along the circumferential direction within the analysis target region is obtained each time the table is rotated once. Then, each time the analysis conditions are changed, the detection data of elements (or bond states) obtained from within the analysis target region is stored in separate storage areas by the storage means. Then, when the table is rotated a number of times corresponding to the preset number of elements (or bond states), the movement control section moves the table a predetermined distance in the radial direction.

Subsequently, the table is rotated a number of times corresponding to the preset number of elements (or bond states), and the analysis conditions are changed for each rotation. In this way, the above operations are sequentially repeated.

(F) Embodiment FIG. 1 is a block diagram of a surface analysis apparatus (XP'S in this embodiment) according to an embodiment of the present invention. In the same figure, the symbol l is
The entire PS is shown, where 2 is the sample and 4 is the rθ drive mechanism. This r-θ drive mechanism 4 is provided so that a disk-shaped table 6 on which the sample 2 is placed is rotatable in the circumferential direction (θ direction) and movable in the radial direction (r direction). This table 6 is individually driven in the circumferential direction and the radial direction by pulse motors 8 and 1O. 12 is an X-ray gun that irradiates the sample 2 with soft X-rays, 14 is an analyzer that separates the energy of photoelectrons excited and emitted from the sample 2, 16 is a detector that detects the photoelectrons sorted by the analyzer 14, and 18 is an analyzer voltage control section that controls the analyzer voltage applied to the analyzer 14.

20 is the number of elements (or bonding states) to be analyzed,
This is a setting section for setting analysis conditions, etc.
For example, it consists of a keyboard, etc.

Reference numeral 22 denotes a microcomputer, which includes a memory 24 such as a DRAM, a sequence control section 26 that performs sequence control based on data set by the setting section 20, and a counter 28 that counts the number of changes each time the analyzer voltage is changed. , a rotation control unit 30 that outputs a control signal to continuously rotate the pull 6 in one direction by a number of times corresponding to the number n of elements (or bonding states) based on the output of the counter 28; a movement control unit 32 that outputs a control signal to move the table 6 by a predetermined distance in the radial direction when the table 6 is rotated a number of times corresponding to the number n of elements (or bond states) set in advance; A gate circuit 34 is provided for extracting only the detection signals from within the analysis target region among the detection signals output from the detector 16. Then, the sequence control section 26 described above is configured to:
It corresponds to an analysis condition control section that outputs a control signal for switching to analysis conditions adapted to the detection of each element (or bond state) each time the table 6 is rotated over the analysis target region set by the setting section 20. . Furthermore, the sequence control section 26 and the memory 24 store detection data of elements (or bond states) obtained from within the analysis target region every time the analysis conditions are changed by the analysis condition control section as defined in the claims. A storage means is configured to store data in each individual storage area of the memory 24.

Note that 36 is a D/A converter that converts data of a two-dimensional distribution image of each element (or bond state! event) stored in the memory 24, and 38 is a display device such as a CRT monitor.

Next, we will explain the operation when applying xpst with the above configuration to obtain a two-dimensional distribution image of elements (or bonds) present in the analysis target region of sample 2, as shown in the flowchart shown in Fig. 2 and Fig. 3. This will be explained with reference to the explanatory diagrams shown in FIG.

First, the number n1 of elements (or bonding states) to be analyzed is determined by the setting unit 20.
analysis conditions adapted to detect (in this case, each analyzer voltage E3, E6,...En), analysis target area (marked A with the rotation axis O of the table 6 as the center in Fig. 3),
Rotation angle θ and radial distance r1 to determine the fan-shaped area surrounded by BCD) Step widths θs and rs in the circumferential direction and radial direction necessary to determine the data collection point, and the analysis start point (rt, θ1) Manually set each (
Step ■).

When the analysis starts, first, the sequence control unit 26
Since the angle θ1 of the analysis starting point is given to the rotation control unit 30, and the distance r of the analysis starting point is given to the movement control unit 32, the rotation control unit 30 and the movement control unit 3 are
2 drive and control the pulse motors 8 and 10, respectively. Therefore, the table 6 is moved to the desired analysis starting point (rt, θυ) (step ■).The sequence control unit 26 also activates the X-ray gun 12 to generate soft X-rays.

Subsequently, the sequence control section 26 outputs a control signal for setting the analyzer voltage to the analyzer voltage control section 18. In response, the analyzer voltage control unit 18 controls the analyzer 14 to determine the specific element (or bonding state).
A predetermined analyzer voltage (initially E,) suitable for detection of is applied. In parallel with this setting of the analyzer voltage, the sequence control section 26 outputs a count pulse to the counter 28, and sets the count value k of the counter 28 to "l" (step 2). The rotation control section 30 continues to rotate the table 6 by driving the pulse motor 8 until the counter 28 counts up. Along with this, sample 2
is rotated continuously, for example counterclockwise. Further, the sequence control unit 26 opens the gate circuit 34 while the table 6 is rotated by a predetermined angle θ. Therefore, while the analysis start point (r5, θ,) is rotated by a predetermined angle θ at a distance of radius rt, the detection data of one specific element (or bonding state) existing on the arc is The data is sampled every θS and stored in a predetermined storage area of the memory 24 (steps ① to ①).

When the table 6 is rotated by a certain angle θ and the detected data reaches a predetermined number of sampling points, the sequence control section 26 closes the gate circuit 34 and then increments the count value of the counter 28 by one (step 2).

At that time, if the counter 28 does not count up (
In step ■), since analysis has not yet been performed for the number n of elements (or bond states) to be analyzed (step ■), the sequence control unit 24 outputs a control signal to the analyzer voltage control unit 18 to The voltage can be changed to the following elements (
or binding state) to the values necessary for detection.
The rotation control unit 30 drives the pulse motor 8 to continue rotating the table 6 (step 2). Then, when the table 6 rotates once and returns to the original analysis starting point (rt, θ1), the process returns to step (2) and the next element (or bonding state) is analyzed. In this way, the table 6 is continuously rotated in one direction a number of times corresponding to the number n of elements (or bonding states) set in advance by the setting unit 20, and each time the table 6 is rotated once, the area to be analyzed is Detection data of each element (or bonding state) existing along the circumferential direction of the sensor is individually stored in the storage area of the memory 24 (steps ① to ②).

Then, when the table 6 is rotated the number of times corresponding to the preset number n of elements (or bonding states), the count value of the counter 28 becomes kh<k>n and counts up (step ■). In response, the rotation control unit 30 rotates the table 6 to return to the original analysis starting point (r+,
θl) (step @l), the movement control unit 32 moves the table 6 in a predetermined step width r in the radial direction.
Move by s (step ■). As a result, the analysis starting point is changed from (r+, θl) to (r+ rs, θl). At this point, if the number of detection data along the radial direction has not reached the predetermined number of sampling points (step @), the analysis within the analysis target area has not yet been completed, so return to step ■ and return to the analysis starting point. The above-described operation is repeated starting from (r, -rs, θ,). Then, when the detection data along the radial direction reaches a predetermined number of sampling points (step 0), the analysis of all elements (or bond states) present in the analysis target region is completed. Then, if the data stored in the memory 24 is read out as necessary, a two-dimensional distribution image for each element (or bond state) will be displayed on the display 38.

(G) Effects of the Invention According to the present invention, the table on which the sample is placed does not need to be reciprocated as in the conventional case, and both rotation in the circumferential direction and movement in the radial direction are always only in a constant direction. Since the device is driven, excellent effects such as two-dimensional distribution images of multiple elements (or bond states) can be obtained simultaneously with a relatively simple control sequence can be achieved.

[Brief explanation of drawings]

FIG. 1 shows a surface analysis device (especially XP) according to an embodiment of the present invention.
S), Fig. 2 is a flowchart of the control procedure of the device, Fig. 3 is an explanatory diagram of the table drive operation, Fig. 4 is a plan view of the table of the r-θ drive mechanism, and Fig. 5 is the conventional FIG. 3 is an explanatory diagram of a table driving operation. ■...XPS, 2...sample, 4...r-θ drive mechanism, 6...table, 12...X-ray gun, 14...
Analyzer, 20... Setting section, 24... Memory, 2
6... Sequence control section (analysis condition control section), 30.
...Rotation control section, 32...Movement control section.

Claims (1)

[Claims] (1) The table on which the sample is placed can rotate in the circumferential direction,
In addition, in a surface analysis device equipped with a −θ drive mechanism that is movable in the radial direction, the element to be analyzed (
A setting section for setting the number of elements (or bonding states), analysis conditions adapted to detecting each element (or bonding state), and analysis target area, and the elements (or bonding states) set in this setting section. a rotation control unit that outputs a control signal to continuously rotate the table in one direction by a number of times corresponding to the number of elements; ); and an analysis condition control unit that outputs a control signal to switch to analysis conditions suitable for the detection of A movement control unit outputs a control signal to move the table a predetermined distance in the radial direction, and the analysis condition control unit detects elements (or bond states) obtained from within the analysis target region every time the analysis conditions are changed. A surface analysis device comprising: storage means for storing data in separate storage areas.