JP2022089263A - Structure measuring system, structure measuring method, processing apparatus, and processing program - Google Patents

Abstract

To provide a structure measuring system, a structure measuring method, a processing apparatus, and a processing program that can measure an irregularity structure of a metal surface in a non-contact manner.SOLUTION: A structure measuring system measures an irregularity structure of a metal surface. The structure measuring system comprises: a light source 30 that irradiates the metal surface with light in a predetermined wavelength region; an optical receiver 36 that detects return light from the metal surface; and a processing apparatus 10. The processing apparatus 10 includes a first calculation unit 13 and a first evaluation unit 14. The first calculation unit 13 calculates a first return light intensity ratio indicating the intensity of return light from a metal surface to be measured to the intensity of return light from a first reference metal surface whose irregularity height is equal to or less than a predetermined height threshold. The first evaluation unit 14 evaluates the irregularity height of the metal surface to be measured based on the first return light intensity ratio.SELECTED DRAWING: Figure 2

Description

The present invention relates to a structural measurement system, a structural measurement method, a processing apparatus, and a processing program for measuring the uneven structure of a metal surface.

A method for measuring the uneven structure of the substrate surface in a non-contact manner has been proposed. For example, Patent Document 1 discloses a method for identifying minute irregularities of a compound semiconductor layer by irradiating a main surface of a compound semiconductor substrate with measurement light and analyzing the reflected light.

Japanese Unexamined Patent Publication No. 2019-009173

However, the above-mentioned method described in Patent Document 1 cannot measure the uneven structure of the metal surface. Further, the method described in Patent Document 1 can only read the marking, and cannot evaluate specific structural information such as the height of the unevenness of the concave-convex structure forming the marking.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a structure measurement system, a structure measurement method, a processing device, and a processing program capable of measuring the uneven structure of a metal surface in a non-contact manner. It is something to do.

The structure measurement system according to one aspect of the present invention is a structure measurement system that measures the uneven structure of a metal surface. The structure measurement system includes a light source that irradiates the metal surface with light in a predetermined wavelength region, a light receiver that detects return light from the metal surface, and a processing device. The processing device includes a first calculation unit and a first evaluation unit. The first calculation unit is a first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose uneven height is equal to or less than a predetermined height threshold. Is calculated. The first evaluation unit evaluates the unevenness height of the metal surface to be measured based on the first return light intensity ratio. Since this structure measurement system uses the intensity of the return light with respect to the irradiated light, it is possible to measure the height of the uneven structure on the metal surface in a non-contact manner.

Here, the first evaluation unit evaluates that the smaller the first return light intensity ratio, the higher the unevenness height of the metal surface to be measured. As a result, the structure measurement system can acquire specific unevenness height information of the metal surface without contact. Further, the height threshold value is preferably 50 nm or less from the viewpoint of measurement accuracy.

The structure measurement system may include a second calculation unit and a second evaluation unit. The second calculation unit determines the second return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the second reference metal surface whose uneven structure density is equal to or less than a predetermined density threshold. calculate. Further, the second evaluation unit evaluates the uneven structure density of the metal surface to be measured based on the second return light intensity ratio. This allows the structure measurement system to measure the density of the uneven structure on the metal surface in a non-contact manner. Here, the second evaluation unit evaluates that the smaller the second return light intensity ratio, the higher the uneven structure density of the metal surface to be measured. As a result, the structure measurement system can acquire specific uneven structure density information of the metal surface without contact.

Further, the predetermined wavelength region is preferably 1000 nm or less, and is preferably a wavelength region in which the energy absorption rate of the metal contained in the metal surface is equal to or higher than the predetermined absorption rate threshold value. When the height of the concavo-convex structure is on the nano-order, Rayleigh scattering promotes the light confinement effect, which promotes light absorption, so that the return light intensity ratio changes remarkably according to the concavo-convex structure. Because it becomes. Therefore, by irradiating the light in the wavelength region, the measurement accuracy is improved. The metal surface contains copper or aluminum as a main component, and the predetermined wavelength region may be 600 nm or less.

The structure measuring method according to one aspect of the present invention is a structure measuring method for measuring the uneven structure of a metal surface. The structure measuring method includes an irradiation step, a light receiving step, a first calculation step, and a first evaluation step. The irradiation step is a step of irradiating the metal surface with light in a predetermined wavelength region. The light receiving step is a step of detecting return light from the metal surface. In the first calculation step, the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose uneven height is equal to or less than a predetermined height threshold. Is the process of calculating. The first evaluation step is a step of evaluating the unevenness height of the metal surface to be measured based on the first return light intensity ratio. According to this structure measuring method, since the return light intensity with respect to the irradiated light is used, the height of the uneven structure of the metal surface can be measured without contact.

The processing apparatus according to one aspect of the present invention is a processing apparatus for measuring the uneven structure of a metal surface. The processing device includes an acquisition unit, a first calculation unit, and a first evaluation unit. The acquisition unit acquires information on the intensity of the return light from the metal surface, which is detected when the metal surface is irradiated with light in a predetermined wavelength region. The first calculation unit is a first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose uneven height is equal to or less than a predetermined height threshold. Is calculated. The first evaluation unit evaluates the unevenness height of the metal surface to be measured based on the first return light intensity ratio. According to this processing device, since the return light intensity with respect to the irradiated light is used, the height of the uneven structure of the metal surface can be measured without contact.

The processing program according to one aspect of the present invention is a processing program for measuring the uneven structure of the metal surface. The processing program causes a computer to execute an acquisition process, a first calculation process, and a first evaluation process. The acquisition process is a process for acquiring information on the intensity of the return light from the metal surface, which is detected when the metal surface is irradiated with light in a predetermined wavelength region. In the first calculation process, the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose uneven height is equal to or less than a predetermined height threshold. Is the process of calculating. The first evaluation process is a process for evaluating the unevenness height of the metal surface to be measured based on the first return light intensity ratio. According to this processing program, since the return light intensity with respect to the irradiated light is used, the height of the uneven structure of the metal surface can be measured without contact.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a structure measurement system, a structure measurement method, a processing apparatus and a processing program capable of measuring the uneven structure of a metal surface in a non-contact manner.

It is a schematic block diagram of the structure measurement system which concerns on Embodiment 1. FIG. It is a block diagram which shows the functional structure of the processing apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the hardware composition of the processing apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the return light intensity of the Cu material which has a different uneven height. It is a figure which shows the light absorption rate of the Cu material which has a different uneven height. It is a figure which shows the 1st return light intensity ratio of the Cu material which has a different uneven height. It is a figure which shows the light absorption rate of the Al material which has a different uneven height. It is a figure which shows the return light intensity of the Al material which has a different uneven height. It is a flowchart which shows the processing procedure of the processing apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the procedure of the evaluation process of the processing apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the functional structure of the processing apparatus which concerns on Embodiment 2. It is a figure for demonstrating the uneven structure density. It is a figure which shows the return light intensity of the Cu material which has a different uneven structure density. It is a flowchart which shows the procedure of the evaluation processing of the processing apparatus which concerns on Embodiment 2.

Hereinafter, the present invention will be described through embodiments, but the invention according to the claims is not limited to the following embodiments. Moreover, not all of the configurations described in the embodiments are indispensable as means for solving the problem. For the sake of clarity, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are designated by the same reference numerals.

<Embodiment 1>
First, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 10. FIG. 1 is a schematic configuration diagram of the structure measurement system 1 according to the first embodiment. The structure measurement system 1 is a system for measuring the state of the uneven structure of the metal surface. For example, the structural measurement system 1 is installed on a production line of a factory and is used to inspect whether a sample having a metal surface is a good product or a defective product.

This figure shows an example of the sample 2 to be measured. The sample 2 has a substrate 3 and a metal surface 4 formed on the substrate 3. The substrate 3 is a flat plate-shaped member. The substrate 3 is made of a conductive metal material such as Cu or Al, but is not limited to this, and may be a glass substrate or a silicon wafer. The metal surface 4 is a metal thin film formed on the surface of the substrate 3. More specifically, the metal surface 4 is formed on one main surface (surface) of the substrate 3. Here, the metal surface 4 is made of a metal material containing any one of Cu, Al, Sn, Ti and Fe as a main component. The metal surface 4 may be formed integrally with the substrate 3 as a part of the substrate 3.

The metal surface 4 includes a concavo-convex portion 5 having a nano-order fine concavo-convex shape. The uneven portion 5 is formed on the metal surface 4. The uneven portion 5 is made of a metal material containing the same metal (any of Cu, Al, Sn, Ti and Fe) as the main component of the metal surface 4 as the main component.

In the first embodiment, the structure measuring system 1 measures the unevenness height H of the unevenness portion 5 as a state of the unevenness structure. The structure measurement system 1 includes a light source 30, an integrating sphere 32, a light receiver 36, and a processing device 10.

The light source 30 is a light source that irradiates the metal surface 4 with light (irradiation light) in a predetermined wavelength region. The predetermined wavelength region here is a wavelength region used for the evaluation processing of the processing apparatus 10 described later, and is also referred to as an evaluation wavelength. The evaluation wavelength may be 1000 nm or less. The evaluation wavelength may be determined according to the metal as the main component of the metal surface 4. The light source 30 may be a lamp that covers the evaluation wavelength, for example, a deuterium lamp or a halogen lamp. Further, the light source 30 may be a laser having an evaluation wavelength, for example, a semiconductor laser, a YAG SHG laser, a YAG THG laser, an excimer laser, or the like.

The light source 30 irradiates the metal surface 4 of the sample 2 attached to the opening of the integrating sphere 32 opposite to the incident opening through the incident opening of the integrating sphere 32. The incident angle θ may be a predetermined angle, for example, 10 ° or less. The incident angle θ may be determined according to the metal as the main component of the metal surface 4.

The integrating sphere 32 is a hollow sphere member that scatters (diffusely reflects) the irradiation light taken in from the light source 30. The inner surface of the integrating sphere 32 is spherical, and the inner wall thereof is coated with a light scattering material having high reflectance such as barium sulfate.

The light receiver 36 is arranged in the center of the internal space of the integrating sphere 32 and is a light receiver that detects the return light from the metal surface 4. Here, the return light refers to a combination of specularly reflected light and diffusely reflected light. That is, the irradiation light is emitted from the light source 30 and is incident on the metal surface 4 of the sample 2 through the internal space of the integrating sphere 32. Then, the specular reflected light and the diffuse reflected light are repeatedly reflected by the inner wall of the integrating sphere 32, and finally received by the light receiver 36. The light receiver 36 is connected to the processing device 10 and transmits information on the return light intensity to the processing device 10 in response to the detection of the return light.

The processing device 10 is a computer device for measuring and evaluating the uneven structure of the metal surface 4. The processing apparatus 10 calculates and evaluates the state of the uneven structure of the metal surface 4 based on the information of the return light intensity supplied from the light receiver 36. Further, the processing device 10 is connected to the light source 30 and controls irradiation with respect to the light source 30. The processing device 10 may control the movement of the stage (not shown) on which the sample 2 is placed.

FIG. 2 is a block diagram showing a functional configuration of the processing apparatus 10 according to the first embodiment. The processing device 10 includes an irradiation control unit 11, an acquisition unit 12, a first calculation unit 13, a first evaluation unit 14, an output unit 15, and a storage unit 16.

The irradiation control unit 11 is connected to the light source 30, and causes the light source 30 to irradiate the metal surface with irradiation light having a wavelength for evaluation.

The acquisition unit 12 is connected to the light receiver 36, receives the return light intensity information from the light receiver 36, and acquires the information. The acquisition unit 12 supplies the acquired information on the return light intensity to the first calculation unit 13.

The first calculation unit 13 calculates the first return light intensity ratio based on the information of the return light intensity from the metal surface 4 to be measured. Here, the first return light intensity indicates the return light intensity from the metal surface 4 of the sample 2 to be measured with respect to the return light intensity from the first reference metal surface. The first reference metal surface is a metal surface having an uneven structure in which the uneven height H is equal to or less than a predetermined height threshold value. The height threshold is preferably 50 nm or less from the viewpoint of measurement accuracy. The information on the return light intensity from the surface of the first reference metal is stored in advance in the storage unit 16 described later as the first reference surface information 17. The first calculation unit 13 supplies the calculated information on the first return light intensity ratio to the first evaluation unit 14.

The first evaluation unit 14 evaluates the unevenness height H of the metal surface 4 of the sample 2 based on the first return light intensity ratio. Here, the first evaluation unit 14 evaluates that the smaller the first return light intensity ratio, the higher the unevenness height H of the metal surface 4 of the sample 2. This makes it possible to acquire specific unevenness height information on the metal surface without contact. For example, the first evaluation unit 14 determines whether or not the first return light intensity ratio is within a predetermined range, and thus whether or not the unevenness height H of the metal surface 4 of the sample 2 is within the acceptable range. Is determined. Then, the first evaluation unit 14 determines that the sample 2 whose unevenness height is within the acceptable range is a good product. Further, even if the first evaluation unit 14 estimates the value of the unevenness height H of the metal surface 4 of the sample 2 based on the information of the first return light intensity ratio and the unevenness height H of the first reference metal surface. good. The uneven height H of the surface of the first reference metal may be acquired in advance from a cross-sectional SEM (Scanning Electron Microscope) image of the surface of the first reference metal. Then, the first evaluation unit 14 supplies the information of the evaluated unevenness height H to the output unit 15.

The output unit 15 outputs information on the evaluated uneven height H. The output unit 15 may include a display unit (not shown) that displays information on the unevenness height H or a voice output unit (not shown) that outputs voice. Further, the output unit 15 may include a transmission unit (not shown) that transmits information of the unevenness height H to an external device (not shown) communicably connected to the processing device 10.

The storage unit 16 is a storage medium that stores information necessary for information processing of the processing device 10. In the first embodiment, the storage unit 16 stores the first reference plane information 17.

FIG. 3 is a block diagram showing a hardware configuration of the processing device 10 according to the first embodiment.

The processing device 10 has a processor 100, a ROM 101 (Read Only Memory), a RAM 102 (Random Access Memory), and an interface unit 103 (IF; Interface) as a main hardware configuration. The processor 100, ROM 101, RAM 102, and the interface unit 103 are connected to each other via a data bus or the like.

The processor 100 has a function as an arithmetic unit that performs control processing, arithmetic processing, and the like. The processor 100 may be a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (field-programmable gate array), a DSP (digital signal processor), an ASIC (application specific integrated circuit), or a combination thereof. The ROM 101 has a function for storing a control program, an arithmetic program, and the like executed by the processor 100. The RAM 102 has a function for temporarily storing processing data and the like. The interface unit 103 inputs / outputs signals to and from the outside via wired or wireless. Further, the interface unit 103 accepts the operation of inputting data by the user and displays the information to the user. For example, the interface unit 103 communicates with the light source 30 and the light receiver 36.

Hereinafter, the relationship between the unevenness height H and the first return light intensity ratio, which is a prerequisite for the evaluation process by the first evaluation unit 14, will be described. First, an example of the method for producing the sample 2 will be described.

(Method for preparing sample 2)
First, a metal member (hereinafter referred to as a pre-metal member) before the uneven portion 5 is formed is prepared. The pre-metal member is provided with a metal surface 4, and is made of a metal material containing any one of Cu, Al, Sn, Ti, and Fe as a main component. Here, a case where the metal surface 4 is made of a metal material containing Cu as a main component (hereinafter referred to as Cu material), for example, C1100 material will be described as an example. Next, a pulse laser is applied to a predetermined region of the metal surface 4 provided on the pre-metal member. As a result, a part of the metal surface 4 in the predetermined region is melted, the molten metal evaporates, and is released into the gas atmosphere to become metal vapor. After that, the metal vapor becomes particles by condensation or reaction with gas, and is deposited and solidified on the metal surface 4. By repeating this in each region of the metal surface 4, the uneven portion 5 is formed. The irradiation conditions of the pulse laser differ depending on the metal as the main component, but in the case of C1100 material, for example, the peak output is 10 kW or more, the pulse width is 1 to 1000 ns, the laser spot diameter is 75 μm or less, and the spot interval is 59 μm or less. Is. Here, by changing the irradiation conditions of the pulse laser, metal surfaces having different uneven heights H are produced.

(Relationship between uneven height H and first return light intensity ratio)
Next, the relationship between the unevenness height H and the first return light intensity ratio will be described. FIG. 4 is a diagram showing the return light intensity of Cu materials having different uneven heights H. The horizontal axis of this figure indicates the wavelength [nm] of the irradiation light of the light source 30, and the vertical axis indicates the return light intensity [%]. The return light intensity in this figure was measured at 200 to 2000 [nm] using an ultraviolet visible spectrophotometer (SolidSpec-3700 manufactured by SHIMADZU). The dotted line in the figure shows the return light intensity of the sample 2 (“H_high”) having a high unevenness height H, and the solid line shows the return light intensity of the sample 2 (“H_medium”) having a medium unevenness height H. The alternate long and short dash line indicates the return light intensity of sample 2 (“H_low”) having a low uneven height H. According to a cross-sectional SEM image (not shown), the uneven height H of "H_high" in this figure is 123 [nm], the uneven height H of "H_medium" is 69.0 [nm], and the uneven height of "H_low". It is known that H is 27.8 [nm].

As shown in this figure, the return light intensity due to light irradiation converges to 0 macroscopically as the wavelength becomes shorter, regardless of the unevenness height H, if a nano-order uneven structure is formed on the entire surface. .. It is considered that this is because light is scattered by Rayleigh scattering and the scattered light is absorbed by the metal surface by surface plasmon resonance.

FIG. 5 is a diagram showing the light absorption rate of Cu materials having different uneven heights. The light absorption rate is a value obtained by subtracting the return light intensity and the transmitted light intensity from the incident light intensity, but since the transmitted light intensity is close to 0 in this example, it is calculated by subtracting the return light intensity from the incident light intensity. To. As shown in this figure, the light absorption rates of "H_high", "H_medium" and "H_low" show high values at 600 nm or less. This indicates that the light absorption characteristics of the metal surface 4 having the nano-order uneven structure are similar to the light absorption characteristics of the bulk of the main component metal. Therefore, it can be seen that the “H_high”, “H_medium” and “H_low” metal surfaces 4 are not altered into oxides or the like, and light absorption is generated by surface plasmon resonance in the same manner as pure metal. ..

Here, in order to see the influence of the unevenness height H on the return light intensity with respect to the irradiation light in the wavelength region where the energy absorption rate in the bulk of the main component metal is 1000 nm or less, particularly in the bulk of the main component metal, “H_high” and “H_medium”. The value obtained by dividing each return light intensity of "H_low" by the return light intensity of "H_low" is calculated, and this is defined as the first return light intensity ratio A. That is, in this example, the “H_low” metal surface 4 is the first reference metal surface. However, the first reference metal surface is not limited to this, and may be a metal surface 4 having an uneven height H determined according to the metal contained as a main component, for example, a metal surface having an uneven height H of 50 nm or less. It may be 4. The energy absorption rate of the main component metal in bulk may be a spectral emissivity, and can be obtained by, for example, measuring the surface temperature of a metal member with a radiation thermometer.

FIG. 6 is a diagram showing a first return light intensity ratio A of Cu materials having different uneven heights. The dotted line in the figure shows the first return light intensity ratio A of "H_high", and the solid line shows the first return light intensity ratio A of "H_medium". As shown in this figure, the first return light intensity ratios A of “H_high” and “H_medium” are both smaller than 1 in the entire measurement wavelength region. The higher the unevenness height H, the smaller the first return light intensity ratio A, and this tendency is that the shorter the wavelength, the more specifically the wavelength region below the wavelength region in which the bulk energy absorption rate of the main component metal is high. And it has become remarkable. In the case of Cu material, the wavelength region below the wavelength region where the energy absorption rate is high is 600 nm or less.

This can be explained as follows. That is, the higher the unevenness height H, the greater the Rayleigh scattering that occurs on the short wavelength side, and the light is confined in the unevenness structure. The greater the light confinement effect, the more the light absorption due to surface plasmon resonance is promoted. As a result, the first return light intensity ratio A on the short wavelength side of "H_high" is smaller than the first return light intensity ratio A on the short wavelength side of "H_medium", which has a lower uneven height H.

The relationship between the uneven height H and the first return light intensity ratio when the metal surface 4 is a Cu material has been described above, but it is composed of another metal material, for example, a metal material (Al material) containing aluminum as a main component. The same applies to the case where it is done.

FIG. 7 is a diagram showing the light absorption rate of Al materials having different uneven heights. For example, the Al material is A1050. As shown in this figure, the light absorption rates of "H_high", "H_medium" and "H_low" have the first peak near 300 nm (p1) and the second peak near 800 to 900 nm. (P2). This indicates that the light absorption characteristics of the metal surface 4 having the nano-order uneven structure are similar to the light absorption characteristics of the bulk of the main component metal. Therefore, with respect to the Al material, the “H_high”, “H_medium” and “H_low” metal surfaces 4 do not deteriorate into oxides or the like, and light absorption occurs due to surface plasmon resonance as in the case of pure metal. You can see that.

As for the Al material, the influence of the unevenness height H of the return light intensity becomes remarkable in the wavelength region of 1000 nm or less, particularly in the wavelength region where the energy absorption rate in the bulk of the main component metal is high. FIG. 8 is a diagram showing the return light intensity of Al materials having different uneven heights. As shown in this figure, the return light intensity decreases in the order of "H_low", "H_medium", and "H_high". Therefore, assuming that the first reference metal surface is the metal surface 4 of "H_low", the first return light intensity ratio A of "H_high" is the first return light intensity ratio of "H_medium" having a lower uneven height H. It is smaller than A. And such a tendency becomes remarkable on the short wavelength side, especially in the vicinity of the wavelength region corresponding to the first peak (p1) in FIG. 7.

As described above, on the short wavelength side, the higher the unevenness height H, the smaller the first return light intensity ratio A. Therefore, the first evaluation unit 14 determines that the metal surface 4 of the sample 2 is based on the first return light intensity ratio A. The unevenness height H can be evaluated. The evaluation wavelength is preferably a wavelength or a wavelength region in which the energy absorption rate of the metal (bulk) contained in the metal surface 4 as a main component is equal to or higher than a predetermined absorption rate threshold value. As an example, when the metal surface 4 is a Cu material or an Al material, the evaluation wavelength is 600 nm or less. If it is 600 nm or less, the frequency of Rayleigh scattering increases and light absorption is promoted. Therefore, the difference in the first return light intensity ratio A due to the unevenness height H appears remarkably, and the evaluation accuracy is improved. When the metal surface 4 is an Al material, the evaluation wavelength is more preferably 400 nm or less in accordance with the first peak.

FIG. 9 is a flowchart showing a processing procedure of the processing apparatus 10 according to the first embodiment.
First, the main surface of the metal surface 4 is virtually divided into n sections (n is a natural number). The area per section is, for example, an area that can be irradiated by the light source 30 at one time. Then, the processing apparatus 10 repeats the following steps S10 to 12 for each section.

First, the irradiation control unit 11 of the processing device 10 transmits a control signal to the light source 30 to irradiate the region of the i-th section of the metal surface 4 of the sample 2 with irradiation light in a predetermined wavelength region (step). S10; light irradiation step). In this example, when the metal surface 4 is a Cu material, the wavelength of the irradiation light is 600 nm or less, and the incident angle θ is 8 °. Even when the metal surface 4 is an Al material, the wavelength of the irradiation light is 600 nm or less, and the incident angle θ is 8 °.

As a result, the light receiver 36 detects the return light from the metal surface 4 (step S11; light receiving step). Then, the acquisition unit 12 of the processing device 10 acquires information on the return light intensity of the corresponding section from the light receiver 36 (step S12). The acquisition unit 12 may store the information on the return light intensity acquired in the storage unit 16.

Then, in step S13, the first calculation unit 13 and the first evaluation unit 14 of the processing device 10 execute the evaluation process described later.

In step S14, the output unit 15 of the processing device 10 outputs the evaluation result and ends the processing. In this example, the output unit 15 outputs whether the sample 2 is a good product or a defective product.

FIG. 10 is a flowchart showing a procedure of evaluation processing of the processing apparatus 10 according to the first embodiment. The initial value of the section number i is 1.

First, the processing device 10 determines whether or not the section number i is equal to or less than the total number of sections n (step S20). As a result, the processing apparatus 10 determines whether or not the entire metal surface 4 has been measured. When the section number i exceeds the total number of sections n (NO in step S20), the processing apparatus 10 determines that the metal surface 4 as a whole is a roughened surface of a good product (step S21), and ends the processing. On the other hand, when the section number i is equal to or less than the total number of sections n (YES in step S20), the processing device 10 advances the processing to step S22.

In step S22, the first calculation unit 13 of the processing device 10 uses the first reference plane information 17 of the storage unit 16 and the information of the return light intensity of the i-th section to make the first return of the i-th section. The light intensity ratio A is calculated. This step is called the first calculation step. When the evaluation wavelength has a predetermined width, the first calculation unit 13 first calculates the average value of the return light intensity of the i-th section in the evaluation wavelength region. Then, the first calculation unit 13 divides the average value of the return light intensity of the i-th section by the average value of the return light intensity of the surface of the first reference metal in the evaluation wavelength region, and the obtained value is the i-th. Let the first return light intensity ratio A of the section be. The first calculation unit 13 supplies the information of the first return light intensity ratio A of the i-th section to the first evaluation unit 14.

Next, in step S23, the first evaluation unit 14 determines whether or not the first return light intensity ratio A in the i-th section is within a predetermined range. This step is called the first evaluation step. In this example, the first evaluation unit 14 determines whether or not the first return light intensity ratio A in the i-th section is larger than the predetermined number d and smaller than the predetermined number e. When the first return light intensity ratio A of the i-th section is within the predetermined range (YES in step S23), the first evaluation unit 14 determines that the unevenness height H of the i-th section is acceptable (YES). Step S24), the value of i is incremented (step S27), and the process returns to step S20. That is, the first evaluation unit 14 advances the evaluation of the unevenness height H in the next section.

On the other hand, when the first return light intensity ratio A of the i-th section is out of the predetermined range (NO in step S23), the first evaluation unit 14 determines that the unevenness height of the i-th section is rejected. (Step S25), and the overall NG rate is calculated. The total NG rate is the ratio of the cumulative number of rejected sections to the total number of sections n, and is a percentage in this example. The first evaluation unit 14 determines whether or not the overall NG rate is smaller than the predetermined number f (step S26), and if it is smaller (YES in step S26), proceeds to step S27. On the other hand, when the overall NG rate becomes a predetermined number f or more (NO in step S26), the first evaluation unit 14 determines that the metal surface 4 is a roughened surface of the defective product as a whole (step S28). , End the process.

The first evaluation unit 14 determined whether the metal surface of the sample 2 was a good product or a defective product, but instead of or in addition to this, the value of the unevenness height H of the metal surface 4 of the sample 2 was estimated. You may. Specifically, for example, the first evaluation unit 14 estimates the unevenness height H of the surface of the first reference metal and the unevenness height H of the i-th section from the first return light intensity ratio A. Then, the first evaluation unit 14 estimates the unevenness height H of the entire metal surface 4 of the sample 2 by taking the average of the estimated unevenness heights H of all the sections.

As described above, according to the first embodiment, the structure measuring system 1 can measure the height of the uneven structure of the metal surface 4 in a non-contact manner. The structure measurement system 1 improves the measurement accuracy by defining the wavelength region of the light source 30 according to the metal contained in the metal surface 4 so that the change in the return light intensity ratio according to the uneven structure remarkably appears. Can be done.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIGS. 11 to 14. The second embodiment is characterized in that the structure measuring system 1 measures the unevenness structure density D in addition to the unevenness height H of the metal surface 4. The structure measurement system 1 according to the second embodiment includes a processing device 10a instead of the processing device 10.

FIG. 11 is a block diagram showing a functional configuration of the processing device 10a according to the second embodiment. The processing device 10a basically has the same configuration and function as the processing device 10, but has a second calculation unit 18 and a second evaluation unit 19, and a storage unit 16a instead of the storage unit 16. Different from 10. The acquisition unit 12 supplies the acquired information on the return light intensity from the metal surface 4 to be measured to the second calculation unit 18 in addition to the first calculation unit 13.

The second calculation unit 18 calculates the second return light intensity ratio based on the information of the return light intensity from the metal surface 4 to be measured. Here, the second return light intensity ratio indicates the return light intensity from the metal surface 4 to be measured with respect to the return light intensity from the second reference metal surface. The second reference metal surface is a metal surface having an uneven structure in which the uneven structure density D is equal to or less than a predetermined density threshold. The uneven structure density D and the density threshold value will be described later. Information on the return light intensity from the surface of the second reference metal is stored in advance in the storage unit 16a, which will be described later, as the second reference plane information 20. The second calculation unit 18 supplies the calculated information on the second return light intensity ratio to the second evaluation unit 19.

The second evaluation unit 19 evaluates the uneven structure density D of the metal surface 4 to be measured based on the second return light intensity ratio. Here, the second evaluation unit 19 evaluates that the smaller the second return light intensity ratio, the higher the uneven structure density D of the metal surface 4 to be measured. This makes it possible to acquire specific uneven structure density information on the metal surface without contact. For example, the second evaluation unit 19 determines whether or not the second return light intensity ratio is within a predetermined range, and thus whether or not the uneven structure density D of the metal surface 4 of the sample 2 is within the acceptable range. Is determined. Then, the second evaluation unit 19 determines that the sample 2 having the unevenness height H and the unevenness structure density D within the acceptable range is a good product. Further, the second evaluation unit 19 may estimate the value of the uneven structure density D of the metal surface 4 of the sample 2 based on the information of the second return light intensity ratio and the uneven structure density D of the second reference metal surface. good. The second evaluation unit 19 supplies the information of the evaluated uneven structure density D to the output unit 15.

The storage unit 16a stores the second reference plane information 20 in addition to the first reference plane information 17.

FIG. 12 is a diagram for explaining the uneven structure density D. This figure is a top view of the metal surface 4 of the sample 2. The uneven structure density D is calculated based on the uneven structure spacing d, and the larger the uneven structure spacing d, the smaller the uneven structure density D. In the second embodiment, the uneven structure density D may be the reciprocal of the gap area S per unit area calculated based on the interval d of the uneven structure. The gap area S per unit area is calculated from the gap area s between the uneven structures calculated based on the interval d of the uneven structures and the number of uneven structures per unit area.

(Relationship between uneven structure density D and second return light intensity ratio)
Hereinafter, the relationship between the uneven structure density D and the second return light intensity ratio will be described. The preparation of the sample 2 is the same as that of the first embodiment, and a metal surface having a different uneven structure density D is prepared by changing the irradiation conditions of the pulse laser.

FIG. 13 is a diagram showing the return light intensity of Cu materials having different uneven structure densities. The horizontal axis of this figure indicates the wavelength [nm] of the irradiation light of the light source 30, and the vertical axis indicates the return light intensity [%]. The dotted line in the figure shows the return light intensity of the sample 2 (“D_high”) having a high uneven structure density D, and the solid line shows the return light intensity of the sample 2 (“D_medium”) having a medium uneven structure density D. The alternate long and short dash line indicates the return light intensity of sample 2 (“D_low”) having a low concave-convex structure density D. In this figure, the “D_high” uneven structure density D is 1.22 × 102, the “ ^D_medium ” uneven structure density D is 73.9, and the “D_low” uneven structure density D is 1. That is, in this example, "D_low" is the sample 2 in the case where the uneven structure is not produced.

As shown in this figure, the return light intensity due to light irradiation is scattered by Rayleigh scattering as the wavelength becomes shorter if the nano-order uneven structure is formed to some extent, and macroscopically due to absorption by surface plasmon resonance. It converges to 0. However, even in the short wavelength region, the lower the uneven structure density D, the higher the return light intensity. This is because the effect of Rayleigh scattering is reduced and the specular reflected light is increased. This tendency is remarkable in the wavelength region below the wavelength region where Rayleigh scattering occurs and the energy absorption rate of the bulk of the main component metal is high, as in the case of the unevenness height H. In the case of the Cu material in this figure, this tendency is remarkable at 600 nm or less. Although not shown, this tendency is more pronounced at 600 nm or less and more prominently at 400 nm or less even in the case of Al material.

Therefore, in the second embodiment, the processing apparatus 10a calculates a value obtained by dividing the respective return light intensities of "D_high" and "D_medium" by the return light intensity of "D_low", and this is the second return light. The intensity ratio is R. That is, in this example, the “D_low” metal surface 4 is the second reference metal surface. However, the second reference metal surface is not limited to this, and may be, for example, a metal surface 4 having an uneven structure density D of 50 or less, more preferably 10 or less.

The evaluation wavelength of the uneven structure density D is a wavelength or a wavelength region in which the energy absorption rate of the metal contained in the metal surface 4 as a main component is equal to or higher than a predetermined absorption rate threshold, as in the case of the uneven height H. Is preferable. As an example, when the metal surface 4 is a Cu material or an Al material, the evaluation wavelength is 600 nm or less.

FIG. 14 is a flowchart showing a procedure of evaluation processing of the processing apparatus 10a according to the second embodiment. The step shown in this figure includes steps S30 to 34 instead of step S22 shown in FIG. The same steps as those shown in FIG. 9 will be omitted as appropriate.

First, for the i-th section, the first evaluation unit 14 of the processing apparatus 10a calculates the first return light intensity ratio A, and the second calculation unit 18 calculates the second return light intensity ratio R (step S30). .. At this time, the second calculation unit 18 calculates the second return light intensity ratio R by using the second reference plane information 20 of the storage unit 16 and the information of the return light intensity in the i-th section. Regarding the method of calculating the second return light intensity ratio R, the description of the method of calculating the first return light intensity ratio A is omitted by replacing the surface of the first reference metal with the surface of the second reference metal. The first calculation unit 13 supplies the information of the first return light intensity ratio A of the i-th section to the first evaluation unit 14, and the second calculation unit 18 supplies the second return light intensity ratio R of the i-th section. Information is supplied to the second evaluation unit 19.

Next, in step S31, the second evaluation unit 19 determines whether or not the second return light intensity ratio R in the i-th section is within a predetermined range. In this example, the second evaluation unit 19 determines whether or not the second return light intensity ratio R of the i-th section is larger than the predetermined number a and smaller than the predetermined number b. The second evaluation unit 19 determines that the uneven structure density D of the i-th section is acceptable when the second return light intensity ratio R of the i-th section is within the predetermined range (YES in step S31). (Step S32), and the process proceeds to step S23.

On the other hand, when the second return light intensity ratio R of the i-th section is out of the predetermined range (NO in step S31), the second evaluation unit 19 fails the uneven structure density D of the i-th section. It is determined that there is (step S33), and the total NG rate is calculated (step S34). The second evaluation unit 19 determines whether or not the overall NG rate is smaller than the predetermined number c (step S34), and if it is smaller (YES in step S34), proceeds to step S23. On the other hand, when the overall NG rate is a predetermined number c or more (NO in step S34), the second evaluation unit 19 determines that the metal surface 4 is a roughened surface of the defective product as a whole (step S28). End the process.

In the above example, the second calculation unit 18 has calculated the second return light intensity R, but may simply calculate the return light intensity at the evaluation wavelength or the average value of the return light intensity.

Further, the second evaluation unit 19 determines whether the metal surface of the sample 2 is a good product or a defective product as in the first evaluation unit 14, but instead, the uneven structure density D of the metal surface 4 of the sample 2 The value of may be estimated. For example, the second evaluation unit 19 estimates the uneven structure density D of the surface of the first reference metal and the uneven structure density D of the i-th section from the second return light intensity ratio R. Then, the first evaluation unit 14 estimates the uneven structure density D of the entire metal surface 4 of the sample 2 by taking the average of the estimated uneven structure densities D of all the sections.

As described above, according to the second embodiment, the structure measuring system 1 can measure the uneven structure density in addition to the height of the uneven structure of the metal surface 4 in a non-contact manner. The structure measurement system 1 improves the measurement accuracy by defining the wavelength region of the light source 30 according to the metal contained in the metal surface 4 so that the change in the return light intensity ratio according to the uneven structure remarkably appears. Can be done.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. For example, in the first and second embodiments, the processing devices 10 and 10a are supposed to perform irradiation control of the light source 30 and movement control of the stage of the sample 2, but this function may be omitted.

Further, in the second embodiment, in the processing apparatus 10a, the evaluation target is both the unevenness height H and the unevenness structure density D, but instead, only the unevenness structure density D may be used. In this case, the first calculation unit 13 and the first evaluation unit 14 of the processing device 10a may be omitted.

In the above-described embodiment, the present invention has been described as a hardware configuration, but the present invention is not limited thereto. INDUSTRIAL APPLICABILITY The present invention can also realize various processes related to the structure measurement method by causing a processor to execute a computer program, for example, a process program.

In the above example, the program can be stored and supplied to the computer using various types of non-transitory computer readable medium. Non-temporary computer-readable media include various types of tangible storage media. Examples of non-temporary computer-readable media include magnetic recording media (eg, flexible disks, magnetic tapes, hard disk drives), optomagnetic recording media (eg, optomagnetic disks), CD-ROMs (Read Only Memory), CD-Rs. Includes CD-R / W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transient computer readable media. Examples of temporary computer readable media include electrical, optical, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

In the above-described embodiment, the computer is composed of a computer system including a personal computer, a word processor, and the like. However, the computer is not limited to this, and can be configured by a LAN (local area network) server, a computer (personal computer) communication host, a computer system connected on the Internet, or the like. It is also possible to distribute the functions to each device on the network and configure the computer in the entire network.

1 Structural measurement system 2 Sample 3 Substrate 4 Metal surface 5 Concavo-convex part 10,10a Processing device 11 Irradiation control unit 12 Acquisition unit 13 First calculation unit 14 First evaluation unit 15 Output unit 16, 16a Storage unit 17 First reference surface information 18 2nd calculation unit 19 2nd evaluation unit 20 2nd reference plane information 30 Light source 32 Integrating sphere 36 Receiver 100 Processor 101 ROM
102 RAM
103 Interface section (IF)

Claims (10)

A structural measurement system that measures the uneven structure of a metal surface.
A light source that irradiates the metal surface with light in a predetermined wavelength region,
A receiver that detects the return light from the metal surface, and
Equipped with a processing device
The processing device is
The first calculation unit for calculating the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose unevenness height is equal to or less than a predetermined height threshold. When,
A structural measurement system including a first evaluation unit that evaluates the unevenness height of the metal surface to be measured based on the first return light intensity ratio. The structural measurement system according to claim 1, wherein the first evaluation unit evaluates that the smaller the first return light intensity ratio, the higher the unevenness height of the metal surface to be measured. The structural measurement system according to claim 1 or 2, wherein the predetermined height threshold value is 50 nm or less. A second calculation unit that calculates the second return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the second reference metal surface whose uneven structure density is equal to or less than a predetermined density threshold. ,
The structure measurement system according to any one of claims 1 to 3, further comprising a second evaluation unit for evaluating the uneven structure density of the metal surface to be measured based on the second return light intensity ratio. The structure measurement system according to claim 4, wherein the second evaluation unit evaluates that the smaller the second return light intensity ratio, the higher the uneven structure density of the metal surface to be measured. Any one of claims 1 to 5, wherein the predetermined wavelength region is 1000 nm or less, and the energy absorption rate of the metal contained in the metal surface is equal to or higher than the predetermined absorption rate threshold value. The structural measurement system described in. The metal surface contains copper or aluminum as a main component and contains copper or aluminum as a main component.
The structural measurement system according to claim 6, wherein the predetermined wavelength region is 600 nm or less. It is a structural measurement method for measuring the uneven structure of a metal surface.
An irradiation step of irradiating the metal surface with light in a predetermined wavelength region,
The light receiving step of detecting the return light from the metal surface and
The first calculation step of calculating the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose unevenness height is equal to or less than a predetermined height threshold. When,
A structural measurement method comprising a first evaluation step of evaluating the unevenness height of the metal surface to be measured based on the first return light intensity ratio. A processing device for measuring the uneven structure of a metal surface.
An acquisition unit that acquires information on the intensity of the return light from the metal surface, which is detected when the metal surface is irradiated with light in a predetermined wavelength region.
The first calculation unit for calculating the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose unevenness height is equal to or less than a predetermined height threshold. When,
A processing apparatus including a first evaluation unit that evaluates the unevenness height of the metal surface to be measured based on the first return light intensity ratio. A processing program for measuring the uneven structure of a metal surface.
An acquisition process for acquiring information on the intensity of return light from the metal surface, which is detected when the metal surface is irradiated with light in a predetermined wavelength region.
The first calculation process for calculating the first return light intensity ratio indicating the return light intensity from the metal surface to be measured with respect to the return light intensity from the first reference metal surface whose unevenness height is equal to or less than a predetermined height threshold. When,
A processing program for causing a computer to perform a first evaluation process for evaluating the unevenness height of the metal surface to be measured based on the first return light intensity ratio.

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