JPH03225201A - Instrument for measuring sectional shape of fine hole - Google Patents

Abstract

PURPOSE:To accurately measure also a fine hole by using a tracer sufficiently thin for inserting it into a fine hole, individually measuring shapes of respective single sections and combining respective measured values. CONSTITUTION:A firm 131 is driven in the X direction by a driving part 130. Although the tracer 132 executes circular motion around a pivoting point P, the motion can be regarded as vertical motion in the Z direction if a moving distance is very short. Finally, the tip part of the tracer 132 is driven in the X direction by the driving part 130 while held in a state capable of being auto matically moved in the Z direction. The X and Z direction positions of the tip part of the tracer 132 are detected by a detector 120 and transmitted to a control part 200 as an electric signal through a cable 121. Then, a control panel 220 applies a command for measuring work to a measuring part 100. A data combining part 300 combines two locus data.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a device for measuring the cross-sectional shape of a microhole, and in particular, a device for measuring the cross-sectional shape of a microhole formed on a substrate such as a shadow mask using a stylus. This invention relates to a device for measuring the cross-sectional shape of micropores.

[Conventional technology]

2. Description of the Related Art Substrates with microholes formed therein, including shadow masks, are used in various technical fields.

In recent years, photoetching technology, which has developed along with semiconductor technology, has enabled increasingly finer processing. When such microholes are formed, it is necessary to confirm whether or not the designed microholes have been obtained by measuring the cross-sectional shape of the formed microholes. Generally, the cross-sectional shape of the hole formed in the substrate is 4P1.
The following methods are known to determine this.

(1) Move the tip of the stylus along the inner wall of the hole, and determine the cross-sectional shape of the hole Al1 from the locus of the tip of the stylus.

(2) The cross-sectional shape of the hole is measured without contact by irradiating the inner wall of the hole with light or laser light and observing the reflected light.

(3) Cut the substrate to be measured, polish the cross section, take a microscopic photograph of the polished surface, and measure the cross-sectional shape of the hole.

[Invention or problem to be solved]

However, when trying to measure the cross-sectional shape of micropores with a diameter of several hundred μm using each of the above methods,
The following problems arise.

(1) Conventionally commonly used stylus (needle tip angle 2
4°), when the hole diameter is less than 300 μm, the side part of the stylus contacts the substrate, making it difficult to insert the tip of the stylus to the bottom of the hole, making it impossible to obtain a perfect 4-1 cross-sectional shape. In particular, recent shadow masks often use micropores with intricate cross-sectional shapes, making the conventional method using a stylus inappropriate.

(2) In methods using light or laser light, accurate measurements cannot be made because the reflected light is scattered in the case of micropores with intricate cross-sectional shapes.

(3) In the method of polishing the cross section, the periphery is hardened with resin to prevent deformation, and then the cross section of the hole is polished to the desired cross-sectional position. However, there is a problem in that the process of hardening with resin usually takes 30 minutes, which is too time-consuming. In addition, the positioning of the measurement site is inaccurate because it relies on manual polishing work, and furthermore, since the measurement is performed by human visual observation on a microscopic photograph, inaccurate measurements with measurement errors of about several μm occur. The problem is that it can only be done.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a microhole cross-sectional shape measuring device that can easily measure the accurate cross-sectional shape of a microhole.

[Means to solve the problem]

The present invention provides an apparatus for measuring the cross-sectional shape of a microhole formed in a sample substrate cut along a measurement plane perpendicular to the substrate surface, comprising: an inclined holding means for holding the sample substrate at a predetermined angle; A stylus that is thin enough to be inserted into the microhole of interest, and a stylus that is movable in a first direction within the measurement plane and a second stylus that is perpendicular to the first direction within the measurement plane. a stylus driving means that causes the stylus to draw a locus related to the inner surface of the microhole by driving in two directions; and a locus data holding means that holds the locus drawn by the stylus as data by the stylus driving means. a rotation means capable of rotating the sample substrate by 180 degrees about an axis parallel to the first direction;
Trajectory data obtained before rotation and 180”
data synthesis means for reading locus data obtained after rotation from the locus data holding means, inverting one data and synthesizing both data to obtain cross-sectional shape data about the microhole; An output means for outputting cross-sectional shape data obtained by the means, and the following are provided.

[For production]

The microhole cross-sectional shape measuring device according to the present invention uses a stylus that is sufficiently thin to be inserted into the microhole. Furthermore, rather than measuring the cross section of the micropore all at once, the cross section of each column is measured separately and these are combined later, which allows for sufficiently accurate measurements even for micropores of 7Lf1300μm or less. becomes possible. Since cross-section synthesis processing can be performed using a computer, the measurement work is very easy.

〔Example〕

The present invention will be described below based on an illustrated embodiment. FIG. 1 is a perspective view showing the configuration of a microhole cross-sectional shape measuring device according to this embodiment. This device is composed of an 1111j fixed section 100, a control section 200, and a data synthesis section 300. The detailed configuration of the 4FI fixed section 100 is as follows. A support 111 is attached to the base 110, and the support 111 includes a detector 120 and a drive unit 13.
0 is attached. The drive unit 130 has arm 1.
31 is attached at a point P as a fulcrum, and a stylus 132 is attached to the tip of this arm 131.

On the other hand, the drive unit 130 can drive the arm 131 in the left-right direction in the figure. Therefore, if we pay attention to the movement of the tip of the stylus 132, it will move in the left-right direction in the figure as a result of the drive of the drive unit 130, and will also perform a circular motion around the pivot point P. This circular motion can be regarded as a vertical motion if the distance is very small. FIG. 2 is an enlarged view of the tip of the arm 131 and the stylus 132. The arm 131 is driven by the drive unit 130 in the X direction in the figure. Further, the stylus 132 makes a circular motion with respect to the pivot point P, but if the distance is minute as described above, this can be regarded as an up-and-down motion in the Z direction in the figure. As a result, the tip of the stylus 132 is driven by the drive unit 130 in the X direction in the figure while being held movable in the Z direction in the figure. In addition, arm 13
A fine adjustment weight 133 is attached to the end of the arm 131, and the balance of the arm 131 with respect to the pivot point P can be adjusted. The position of the tip of the stylus 132 in the X and Z directions is detected by the detector 120 and transmitted as an electrical signal to the control unit 200 via the cable 121.

An xy@adjustment table 140 is placed on the platform 110, and a tilt table 141 is placed on top of this. A rotary table 142 is attached to the upper surface of the inclined table 141, and the sample substrate 10 is placed on this rotary table 142. The position is adjusted so that the tip of the stylus 132 comes into contact with the upper surface of the sample base 10. Position adjustment in a plane parallel to the top surface of the platform 110 is performed using the XY fine adjustment table 14.
It is done by 0. Further, the inclination of the sample base tflO can be adjusted by arbitrarily setting the inclination angle of the upper surface of the inclination table 141. Furthermore, the rotating table 142 can freely rotate the sample substrate 10 around an axis parallel to the Z-axis direction in FIG. 2 (the central axis of the support of the tilting table 141).

The CCD camera 150 has a function of taking an enlarged photograph of the positional relationship between the sample substrate 10 and the stylus 132, and the photographed image is recorded on a CRT.
displayed on the monitor 151. The above is the configuration of the measurement section 100.

Next, the detailed configuration of the control unit 200 will be explained.

The electrical signal from the detector 120 is sent to the control box 2.
The data is taken into the CPU in 10 as digital data.

A control panel 220, a CRT monitor 230, a printer 240, and an xy plotter 250 are connected to the control box 210, and a data synthesis section 300 is further connected to the control box 210 via a cable 211. The control panel 220 has a function of giving instructions for measurement work to the measurement section 100. That is, based on this instruction, the drive section 130 drives the arm 131, and the detector 120 outputs position data of the stylus 132.

This position data is data indicating the trajectory of the stylus 132 with respect to the sample substrate 10.

This trajectory data is displayed on the CRT monitor 230 as a measurement result.
displayed on the screen. Further, this all determination result can be output by the printer 240 or the XY plotter 250.

The data synthesis section 300 includes a personal computer main body 3
10, a CRT monitor 320, a keyboard 330, and a mouse 340. The personal computer main body 310 is connected to a CPU in a control box 210 via a cable 211. The function of this data synthesis section 300 is to synthesize two trajectory data, and this function will be explained in detail later.

Now, the measurement principle of this apparatus will be explained by taking as an example a case where a shadow mask is used as the sample substrate 10. FIG. 3 is a partial top view of the shadow mask 10. Although only a portion in which one micropore 11 is formed is shown here, in reality, a large number of such micropores are formed. FIG. 4 shows a cross-sectional view of the shadow mask 10 of FIG. 3 taken along cutting line A-A. The purpose of this device is to measure the cross-sectional shape of a microhole 11 as shown in FIG.

For this purpose, the stylus 132 is inserted into the microhole 11. Figure 5 shows the tip of a stylus commonly used to determine the cross-sectional shape of the hole δP1.
Shown in a). As shown in the figure, a stylus with a tip angle of 24 m and a rounded tip of 25 μm (spherical shape with a radius of 25 μm) is common. On the other hand, in the apparatus of this embodiment, FIG.
), the needle tip angle is 8 @, and the roundness of the tip is 5 μm.
An R stylus is used. In addition to this stylus, the needle tip angle is 16°.
, a stylus with a rounded tip of 5μmR, a needle tip angle of 10@,
A stylus with a rounded tip of 5 μmR was used, and good results were obtained in all cases. In addition, as shown in Fig. 5(C), the tip of the stylus with a tip angle of 16'' is partially cut out,
Good results were also obtained using a stylus with a tip radius of 5 μm.

FIG. 6 is a diagram showing a state in which the stylus 132 shown in FIG. 5(b) is applied to the sample substrate 10. As for the sample substrate 10, its cross section is shown. As mentioned above, the ramp 1
A rotary table 142 is attached on top of 41, and the sample substrate 10 is placed on this rotary table 142. As shown in FIG. 6, a stylus 132 can be inserted into the microhole 11 formed in the sample substrate 10. Now, stylus 1
32 is placed at the position 132-1 in FIG. 6 and is driven in the X direction in the figure. This drive in the X direction is performed by the drive unit 130, as described above, and the stylus 132 is driven in a movable state in the Z direction in the figure. When the stylus 132 is at the position 132-1, its tip comes into contact with the upper surface of the sample substrate 10 due to its own weight. I wanted to, stylus 13
2 is driven in the X direction, its tip touches the sample substrate lO
It will move along the top surface of. Eventually, micropore 1
When reaching the opening of 1, the stylus 132 falls into the microhole 11 and reaches the position of 132-2. Furthermore, the stylus 132
When it is driven in the X direction, its tip passes along the inner wall of the microhole 11 and exits from the microhole 11 through the position 132-3. Then, move along the upper surface of the sample substrate 10 again,
It reaches the position 132-4. Therefore, this stylus 132
The locus of the tip of is as shown by the broken line in FIG.

This locus includes the column cross section 11a of the microhole 11 (indicated by a thick line in the figure).

Now, the rotating table 142 has a central axis C of the column of the tilting table 141.
(indicated by a - dotted chain line in FIGS. 6 and 7) can be rotated by 180 degrees.

In this way, if the trajectory of the stylus 132 is found for the microhole 11 in the same way when rotated by 180@, this trajectory will include the other column cross section 11b of the microhole 11 (see Figure 7). becomes. By combining the two pillar cross sections obtained in this way, a complete cross-sectional shape of the microhole 11 can be obtained. The basic principle of the present invention is to obtain the shapes of the cross sections of the pillars as the trajectories of the stylus and synthesize them to obtain a complete cross section. In order to obtain a cross-sectional shape of micropores with a hole diameter of 300 μm or less, as mentioned above, it is necessary to
It is preferable to use a stylus thinner than μmR). When a conventional stylus 132' is used, as shown in FIG.
It becomes difficult to fully insert it all the way to the bottom.

Next, a specific procedure for AFI determination of the cross-sectional shape of a microhole using this device will be explained based on the flowchart of FIG. 9. First, in step S1, a sample is set. That is, the sample substrate 10 is fixed on the rotating table 142. In this case, instead of using the shadow mask to be measured as it is as the sample substrate 10, it is cut into square chips of, for example, 50 mm x 50 m+i, and the cut chips are used as the sample substrate 10.
It is preferable to place it on the rotary table 142 as a stand. To fix the sample substrate 10 on the rotating table 142, a magnet or double-sided adhesive tape may be used.

Subsequently, in step S2, the tilt table 141 is adjusted. This involves adjusting the position of the microhole 11 to be measured so that it is below the stylus 132 using the XY fine adjustment table 140, and adjusting the inclination angle of the tilt table 141. The angle of inclination is adjusted to an optimum angle so that the tip of the stylus 132 can smoothly draw a trajectory as shown by the broken line in FIG. If the angle is inappropriate, the stylus 132 will get caught on the inner wall of the microhole 11, and smooth movement in the X direction will be hindered. Specifically, it is sufficient to manually move the arm 131 in the X direction and check whether the stylus 132 is caught or not. At this time, if necessary, fine-tune weight 1
33 also performs balance adjustment. If the stylus 132 moves smoothly, the adjustment is complete. In addition, stylus 1
The state of the tip of 32 is photographed by a CCD camera 150 and displayed on a CRT monitor 151. The operator is CR
The T monitor 151 allows the positional relationship between the stylus 132 and the microhole 11 to be confirmed.

In the following step S3, the column cross section is measured. This can be determined by the operator from the control panel 220.
This is done by inputting an instruction to start a fixed period. The drive unit 130 receives this instruction and drives the arm 131 in the X direction at a constant speed. The stylus 132 moves in the vertical direction (Z direction) along the shape of the microhole 11 . This stylus 1
32 in the X and Z directions are detected by the detector 120 and sent as electrical signals to the control box 2.
10. In the end, the control box 210
The internal memory holds trajectory data as shown by the broken line in FIG. An example of this trajectory data is shown in FIG. As mentioned above, this locus data includes the column cross section 11a shown by the bold line in FIG.

In the following step S4, if 7111 of both cross sections is determined or not completed, the sample rotation is performed in step S5. That is, as described above, the turntable 142 is
Rotate. Then, the operation of measuring the column cross section in step S3 is performed again. As a result, locus data as shown in FIG. 10 is obtained again, but the locus data obtained this time includes the other column cross section 11b shown in FIG. 7.

When the measurement of both cross sections is completed in this way, the process proceeds from step S4 to step S6, and data transfer is performed by the operator giving instructions to the control panel 220. That is, a pair of pillar cross-sectional trajectory data is transferred from the memory in the control box 210 to the personal computer main body 310. Steps S7 to S below
ll is a process performed within this personal computer main body 310.

The horizontal process in step S7 is a process to define a horizontal line for each trajectory data. This horizontal line is the sample substrate 10
This line corresponds to the upper surface of the horizontal line H in Fig.
is shown by a broken line. Various methods can be considered for defining the horizontal line.

In this embodiment, a method is adopted in which the operator specifies two points Pi and P2 on the CRT monitor 320. That is, the transferred trajectory data is displayed on the CRT monitor 320.
The screen is displayed as shown in FIG. 10 above, and the operator is asked to specify two points corresponding to the mouth of the microhole 11 using a pointing device such as a mouse 340. 2 points PL
, P2 is specified, a horizontal line H is defined as a straight line connecting these two points, and image rotation processing is performed on the trajectory data so that this horizontal line H is displayed horizontally on the CRT monitor 320. As a result, the trajectory data is displayed on the CRT monitor 320 as shown in FIG. This horizontal processing is performed for each of the pair of column cross-sectional locus data. Therefore, for example, for the other trajectory data, two points Ql and Q2 are specified, and a horizontal line H is defined.

The subsequent horizontal inversion process in step S8 is a process of inverting the left and right sides of one locus data to generate inverted locus data that is, so to speak, a mirror image. For example, as shown in FIG. 11, two points Q1. Regarding the trajectory data that defined Q2,
When the horizontal reversal process is performed, trajectory data as shown in FIG. 12 is obtained.

Subsequently, in step S9, both cross-section synthesis processing is performed. This combines one trajectory data with two points PL and P2 as shown in Fig. 11 and the other reversed trajectory data with two points Ql and Q2 as shown in Fig. 12. It is processing.

This synthesis process may be performed as follows, for example.

In other words, one point PI (or P2) of one trajectory data
and one point Q2 (or Ql) of the other reversal trajectory data.
) and are aligned to the same coordinate point, and both locus data are superimposed on the same coordinate system in such a positional relationship that the horizontal lines H of both locus data overlap with each other. Generally, when two points P1 and Q2 are aligned to the same coordinate point, the two points P2 and Ql are also aligned to almost the same coordinate point. FIG. 13 shows the composite trajectory data obtained in this way.

Next, in step SIO, correction processing is performed. This is a process in which the composite trajectory data obtained in step S9 is corrected to obtain complete cross-sectional shape data. Specifically, in the apparatus of this embodiment, the operator inputs the thickness d of the sample substrate 10 from the keyboard 330.

Generally, the thickness of a sample substrate such as a shadow mask is determined by a standard. In the case of such a sample substrate,
Just input the known thickness as is. If the thickness d is unknown, use a caliper or micrometer to measure the actual A-! do it. The personal computer main body 310 is aligned with the horizontal line H.
Draw another horizontal line ■ at a distance of thickness d from . In this way, as shown in FIG. 14, points A, B, C, and D, which are the intersections of the two horizontal lines H and I and the composite trajectory data, are obtained, and the point-to-point trajectory data from point A to point 6 is calculated. Trajectory data between points, horizontal line outside section AD H1 horizontal line outside section BC■
Displays only the line and erases the other lines. Through such correction processing, complete cross-sectional shape data as shown in FIG. 15 is obtained.

A total of 71111 processes in the subsequent step Sll are additional functions that utilize the arithmetic functions of the personal computer main body 310. For example, a function is added that allows the operator to specify two points A and B as shown in FIG. 16 on the CRT monitor 320, calculates the distance g between these two points AB, and displays this. I can do it. It would also be possible to perform angle calculations such as calculating the angle θ in FIG. 16. Alternatively, it is possible to calculate the cross-sectional area of the microhole 11 as shown by hatching in FIG. 17, or it is also possible to calculate the volume of the microhole 11 by rotating this by 180'.

Finally, output processing is performed in step S12.

This is a process in which complete cross-sectional shape data obtained by the personal computer main body 310 is transferred to the control box 210 via the cable 211, and the cross-sectional shape data is output on paper by the printer 240 or the XY plotter 250. In this way, the operator can obtain the cross-sectional shape data obtained by measurement as a hard copy.

Although the present invention has been described above based on the illustrated embodiment of the apparatus, the present invention is not limited to this embodiment, and various modifications are possible. In particular, various other aspects of the hardware configuration shown in FIG. 1 can be considered. For example, if a node disk is prepared in the control box 210 and the locus data given from the l-1 constant section 100 is saved in this hard disk with a file name, multiple Measurement data regarding micropores can be stored in the hard disk. Furthermore, various additional functions may be provided in the synthesis processing by the data synthesis section 300.

For example, in the above-mentioned embodiment, horizontal processing is performed by two-point instructions from the operator, but if you create a program that performs pattern recognition on trajectory data, you can easily It would be possible to automatically pattern recognize the opening of a hole and automatically define the horizontal line. Also, the display magnification on the CRT monitor 320 or the printer 240 or XY
It is also possible to add a function to appropriately change the output magnification to the plotter 250.

In the apparatus of the above-described embodiment, a complete cross-sectional shape is obtained by combining two pieces of locus data each representing a column cross-section. That is, as shown in Fig. 18, the complete cross-sectional shape is obtained by combining trajectory data including a column cross section made up of section AEB and trajectory data including a column cross section made up of section DFC. .

On the other hand, first partial trajectory data including the cross-sectional section AE, second partial trajectory data including the cross-sectional section DF, third partial trajectory data including the cross-sectional section EB, and cross-sectional section FC.
It is also possible to obtain a complete cross-sectional shape by combining the fourth partial trajectory data including the following. In this case, the first partial trajectory data and the second partial trajectory data are obtained by setting the sample substrate with the substrate surface F1 in the figure facing upward, and
Measurement is performed by inserting the stylus into the microhole from the side, but the third partial locus data and the fourth partial locus data are obtained by setting the sample substrate with the substrate surface F2 in the figure facing upward.
Measurement will be performed by inserting the stylus into the microhole from the second side. Such a measurement method is effective when the micropore has a more intricate cross-sectional shape.

〔Effect of the invention〕

As described above, in the device for determining the cross-sectional shape aPI of a microhole according to the present invention, a stylus that is thin enough to be inserted into the microhole is used, and the shape of each pillar cross-section is determined by API separately. Since the method of synthesis is adopted, sufficiently accurate measurement is possible even for micropores with a pore diameter of 300 μm or less.

Furthermore, since cross-section synthesis processing can be performed using a computer, measurement work becomes extremely easy.

[Brief explanation of drawings]

FIG. 1 shows the cross-sectional shape δp of a microhole according to an embodiment of the present invention.
Figure 2 is an enlarged view of the arm and stylus shown in Figure 1, Figure 3 is a partial enlarged view of the sample substrate to be measured by the apparatus shown in Figure 1, and Figure 4 is a perspective view of the fixed lid device. is a sectional view taken along cutting line A-A of the sample substrate in FIG. 3, FIG. 5(a) is a diagram showing a conventional general stylus, and FIGS. Figure 1 shows an example of a stylus suitable for use in the device shown in Figure 1. Figures 6 and 7 are diagrams showing the principle of cross-sectional shape measurement using the device shown in Figure 1. Figure 8 shows a conventional stylus. 9 is a flowchart showing the measurement procedure using the device shown in FIG. 1, and FIG. 10 is a diagram showing an example of trajectory data obtained with the device shown in FIG. 1. 1st
Figure 1 is a diagram showing data after horizontal processing by the apparatus shown in Figure 1, Figure 12 is a diagram showing data after horizontal reversal processing by the apparatus shown in Figure 1, and Figure 13 is a diagram showing data after horizontal processing by the apparatus shown in Figure 1. 14 is a diagram showing the correction processing by the device shown in FIG. 1, FIG. 15 is a diagram showing complete cross-sectional shape data obtained by the device shown in FIG. 1, 16 and 17 are diagrams showing additional calculation functions of the apparatus shown in FIG. 1, and FIG. 18 is a diagram showing the principle of another embodiment of the present invention. 10...sample substrate, 11...microhole, lla, 11b
... Column cross section, 100 ... Measuring section, 110 ... Base, 111 ... Support column, 120 ... Detector, 121 ...
・Cable, 130... Drive unit, 131... Arm, 132... Stylus, 133... Fine adjustment weight, 1
40...XY@adjustment table, 141...inclined table, 142
...Rotary table, 150...CCD camera, 151...
・CRT monitor, 200...control unit, 210...control box, 211...cable, 220・
...Control panel, 230...CRT monitor,
240...Printer, 250...XY block, 3
00...Data synthesis section, 310...Personal computer main body, 320...CRT monitor, 330...
・Keyboard, 340... Mouse, P... Pivot point,
H, I...horizontal line, d...thickness of the substrate.

Claims (1)

[Claims] A device for measuring the cross-sectional shape of a microhole formed in a sample substrate taken along a measurement plane perpendicular to the substrate surface, the device comprising: an inclined holding device that holds the sample substrate at a predetermined angle; means; a stylus thin enough to be inserted into a microhole to be measured; and a stylus movably in a first direction within the measurement plane, while a stylus driving means that causes the stylus to draw a trajectory related to the inner surface of the microhole by driving in a second direction perpendicular to the first direction; a trajectory data holding means for holding the sample substrate as data; a rotation means capable of rotating the sample substrate by 180 degrees about an axis parallel to the first direction as a rotation axis; The locus data obtained for the microhole and the locus data obtained for the microhole after rotation by 180 degrees are read out from the locus data holding means, one data is inverted and both data are combined, and a cross section about the microhole is obtained. A cross-sectional shape measuring device for micropores, comprising: a data synthesis means for obtaining shape data; and an output means for outputting the cross-sectional shape data obtained by the data synthesis means.