Apparatus and method for inspecting nano-order columnar bodies

Abstract

To provide an inspection device of a nano-order columnar body and an inspection method of the nano-order columnar body, capable of increasing a relative luminance value even if a base material is a low reflection material, and capable of separating a difference in a nano-order columnar body shape level.SOLUTION: An inspection device 10 for a metal columnar body includes an optical path length changing unit 12 on which a measurement target material 21 is placed and which physically changes an optical path length, a vertical epi-illumination 11 that irradiates the measurement target material 21 with light and transmits reflected light from the measurement target material 21, and a luminance meter 13 that measures the reflected light from the measurement target material 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection device and an inspection method for nano-order columns, for example, an inspection device and an inspection method for nano-order columns provided on a low-reflectivity material. [Background technology]

[0002] Patent Document 1 describes a measurement device that aims to improve measurement accuracy by obtaining a clear projected image with reduced blurring, even for translucent objects, without using white powder or the like. The device projects light rays onto the object to be measured, captures the projected image, detects the maximum brightness and the position of maximum brightness, and performs brightness difference maximization processing to maximize the brightness difference between the maximum brightness and the brightness at a distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-14495 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, numerical processing is performed to increase the brightness difference by cutting out low-brightness areas, so when it comes to the purpose of inspection, data truncation often leads to overlooking defective quality, making it unfeasible.In addition, because low-brightness areas are cut out, there is also the problem that low-brightness areas within the original measurement area cannot be detected. [Means for solving the problem]

[0005] In one embodiment, the inspection device and method for nano-order columns amplifies the relative brightness value by changing the optical path length and increasing the difference between each level, making it easier to determine whether the product is good or bad. [Effects of the Invention]

[0006] According to the nano-order columnar body inspection device and nano-order columnar body inspection method disclosed herein, the relative brightness value can be increased even if the base material is a low-reflectivity material, and differences in the shape level of the nano-order columnar bodies can be distinguished. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing an example of an inspection device for nano-order pillars according to a first embodiment. [Figure 2] 10 is a graph showing an example of an inspection result when the optical path length is changed. [Figure 3] 10 is a table showing the influence of luminance on reflection form. [Figure 4] 10 is a graph showing the relationship between a change in optical path length and absolute luminance. [Figure 5] 3 is a flowchart showing an example of a method for inspecting nano-order pillars according to the first embodiment. [Figure 6] 10 is a schematic diagram showing an example of an inspection device for nano-order pillars according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing an example of an inspection apparatus for nano-order columnar bodies according to embodiment 1. In Fig. 1, an inspection apparatus 10 for nano-order columnar bodies includes a vertical epi-illumination illuminator 11, an optical path length changing unit 12, a luminance meter 13, and a control unit 14.

[0009] The vertical incident illuminator 11 irradiates the material 21 to be measured with light and transmits the light reflected from the material 21. For example, the vertical incident illuminator 11 has a white light source 111 and a half mirror 112 that reflects the light from the white light source to the optical path length changing unit 12 and transmits the light from the optical path length changing unit 12 to the luminance meter 13.

[0010] The optical path length changing unit 12 places the material to be measured 21 on it and physically changes the optical path length. For example, the optical path length changing unit 12 has a pantograph jack on which the material to be measured 21 can be placed and which can change the position of the placed material to be measured 21.

[0011] The luminance meter 13 measures the reflected light from the measurement material 21. For example, the luminance meter 13 is preferably a C-MOS (Complementary Metal-Oxide-Semiconductor) camera or a CCD (Charge-Coupled Device) camera.

[0012] The control unit 14 calculates the luminance of the material 21 to be measured based on the light reflected from the material 21 to be measured, which is measured by the luminance meter 13. The control unit 14 is preferably, for example, a computer or an electronic circuit capable of performing arithmetic calculations.

[0013] Next, we will explain the inspection results when the optical path length is changed. Figure 2 is a graph showing an example of the inspection results when the optical path length is changed. In Figure 2, the vertical axis represents relative luminance. The upper graph in Figure 2 shows an example when the optical path length is 430 mm. The lower graph in Figure 2 shows an example when the optical path length is 550 mm. As shown in Figure 2, in the example when the optical path length is 430 mm, the difference in luminance between the two levels is Δ≒1.1, whereas in the example when the optical path length is 550 mm, the difference in luminance between the two levels is Δ≒2.3. In this way, by changing the optical path length, it is possible to increase the relative luminance.

[0014] Next, we will explain the principle of amplification. The reflection characteristics of a sample containing metal pillars are highly directional, with a lot of strong specular reflection light at the same angle to the irradiation direction. If the directionality is high, the change in detected brightness is small even if the optical path length is long. Figure 3 is a table showing the effect of reflection form on brightness.

[0015] On the other hand, the standard white board sample has a diffuse reflection mode, so light is diffused in all directions regardless of the direction of illumination, and the directionality is low. Therefore, when the optical path length is increased, the luminance changes significantly. [Table 1]

[0016] 4 is a graph showing the relationship between the change in optical path length and the absolute luminance, where the vertical axis represents the absolute luminance upon leaving the bed.

[0017] In order to reduce measurement variability, the relative brightness, which is an inspection index, is generally measured simultaneously with a standard white board whose absolute reflectance is guaranteed, and expressed as a relative value. In this case, it is expressed as the quotient of the absolute brightness of the sample containing metal pillars and the standard sample, as shown in the following equation (1). Relative luminance (-) = absolute luminance of sample with metal pillars ÷ absolute luminance of standard sample (1)

[0018] As mentioned above, when the optical path length is increased, only the sample brightness where metal pillars are present is detected as a small change in brightness, resulting in an increase in relative brightness. Utilizing this, differences in each processing level can be clearly detected, making it easier to distinguish between good and bad quality.

[0019] Next, a procedure for inspecting nano-order columnar bodies will be described below. Fig. 5 is a flowchart showing an example of the method for inspecting nano-order columnar bodies according to the first embodiment.

[0020] First, in step S501, light is irradiated onto the material to be measured from the vertical epi-illumination illuminator 11. Then, the process proceeds to step S502.

[0021] In step S502, the light reflected from the material to be measured is captured by the luminance meter 13. Then, the process proceeds to step S503.

[0022] In step S503, the absolute brightness of the metal pillars is detected, and the process proceeds to step S504.

[0023] In step S504, the absolute luminance of the standard white board sample is detected, and the process proceeds to step S505.

[0024] In step S505, the relative luminance is calculated by the control unit 14. Then, the process proceeds to step S506.

[0025] In step S506, the control unit 14 determines whether or not measurement of all levels has been completed. If measurement of all levels has not been completed, the process proceeds to step S507. If measurement of all levels has been completed, the process proceeds to step S508.

[0026] In step S507, the next processing level is prepared, and the process returns to step S501.

[0027] In step S508, ±σ is calculated at each level by the control unit 14. Then, the process proceeds to step S509.

[0028] In step S509, the OK level of -3σ is set, and the process proceeds to step S510.

[0029] In step S510, the NG level is set to +3σ, and the process proceeds to step S511.

[0030] In step S511, it is determined whether the value at -3σ of the OK level is smaller than the value at +3σ of the NG level. If the value at -3σ of the OK level is smaller than the value at +3σ of the NG level, the process ends. If the value at -3σ of the OK level is equal to or greater than the value at +3σ of the NG level, the process returns to step S501.

[0031] Thus, the inspection device and method for nano-order columns according to the first embodiment can increase the relative brightness value even when the base material is a low-reflectivity material, thereby enabling the distinction of differences in the shape level of the nano-order columns. Furthermore, the inspection device and method for nano-order columns according to the first embodiment can increase the difference in the shape level of the nano-order columns even when the shape or surface has a small relative brightness value.

[0032] Embodiment 2 In the second embodiment, an example in which the optical path length is increased by using a prism mirror will be described. FIG. 6 is a schematic diagram showing an example of an inspection apparatus for nano-order columnar bodies according to the second embodiment. In FIG. 6, an inspection apparatus 60 for nano-order columnar bodies includes a vertical epi-illumination illuminator 11, an optical path length changing unit 62, a luminance meter 13, and a control unit 14. In FIG. 6, the same components as those in FIG. 1 are assigned the same numbers, and their description will be omitted.

[0033] 6A, the optical path length changing unit 62 has a prism mirror 621. The prism mirror 621 reflects light from the vertical incident illuminator 11 toward the material to be measured, and reflects light from the material to be measured toward the vertical incident illuminator 11.

[0034] 6B, the optical path length changing unit 62 may include a prism mirror 622 and a prism mirror 623. The prism mirror 622 reflects the light from the vertical epi-illumination illuminator 11 toward the prism mirror 623, and reflects the light from the prism mirror 623 toward the vertical epi-illuminator 11. The prism mirror 623 reflects the light from the prism mirror 622 in the direction of the material to be measured, and reflects the light from the material to be measured back to the prism mirror 622 .

[0035] Thus, according to the inspection of nano-order columnar bodies in embodiment 2, even in the case of a part shape that does not have a measurement surface directly under the light source, resulting in low relative brightness due to the small amount of incident light, the relative brightness value can be increased, and differences in the shape level of the nano-order columnar bodies can be distinguished.

[0036] The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention. For example, by combining the inspection device of embodiment 1 with the prism mirror or other optical path direction changers shown in embodiment 2, the equipment height can be reduced while the relative brightness can be increased. [Explanation of symbols]

[0037] 10, 60 Inspection equipment 11 Vertical epi-illumination 12, 62 Optical path length change unit 13 Luminance meter 14 Control Unit 21 Material to be measured 111 White light source 112 Half Mirror 621, 622, 623 Prism mirror

Claims

1. an optical path length changing unit for placing the material to be measured thereon and physically changing the optical path length; a vertical epi-illumination system that irradiates the material to be measured with light and transmits the light reflected from the material to be measured; An inspection device for nano-order columns, comprising a luminance meter for measuring reflected light from the material to be measured.

2. 2. The inspection device according to claim 1, wherein the optical path length changing section has a pantograph jack on which the material to be measured can be placed and which can change the position of the placed material to be measured.

3. 3. The inspection device according to claim 1, wherein the optical path length changing unit has a prism mirror that reflects light from vertical epi-illumination in the direction of the material to be measured.

4. an optical path length changing unit on which the material to be measured is placed and which physically changes the optical path length; a vertical epi-illumination unit which irradiates the material to be measured with light and transmits the light reflected from the material to be measured; and a luminance meter which measures the light reflected from the material to be measured. The method for inspecting nano-order columnar bodies, wherein the relative brightness is amplified by changing the optical path length using the optical path length changing unit.

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