JPH09126994A - Light absorption measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attempt to improve the reliability and efficiency of the measurement by using a holder which does not interrupt the optical path of an illumination light and holds the acoustic contact condition with sample constant when the light absorption is measured by the acoustic signal generated by the light absorption of sample. SOLUTION: A sample 3 such as a thin film on a glass board generates an acoustic signal by the volumetric change caused by the light absorption of the sample 1 by illuminating a pulse laser. The sample 3 is inserted into a holder H in which liquid (matching material) 4 is fully filled and which is provided at a sample holder 1. Since the light receiving site of the sample 3 is disposed out of the holder H, the optical path is not interrupted. An acoustic detector 6 such as a piezoelectric element is connected to the holder 1 to detect the signal, and to measures it as the light absorption. The liquid 4 is so supplied into the holder H as to hold the level in the holder H constant. At this time, it is desirable to be at a predetermined temperature. Thus, the acoustic contact condition of the sample 3 with the holder 1 is held constant, and the reliability and accuracy of the measurement are improved. The unnecessary overflowed liquid 10 is introduced into a liquid container 2 for reused.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a light absorption measuring device.

[0002]

2. Description of the Related Art With the progress of various optical application technologies, the demand for optical measurement has become more sophisticated. In particular, as a recent trend, attention is being paid to the evaluation of physical properties of light having a wavelength extremely longer or shorter than that of visible light. For example, with light of ultrashort wavelength, various excimer lasers and the like are used for fine processing and lithography, and measurement and evaluation of optical elements and the like are becoming indispensable.

Among the evaluation items required for optical elements and the like, one of the important items is absorption of light. In light absorption measurement (absorption measurement), generally, a method of directly measuring optically (a method of detecting light intensity with an optical sensor) is adopted, but this method has a limit. That is, when the light source light has a short wavelength (200 nm or less), a stable light source and light amount measurement have not been established at present, and it is particularly stable when a minute absorption amount (a minute light amount difference) is observed. Falls.

Further, when a pulse laser such as an excimer laser is used, a problem may occur due to the slow response speed of the optical sensor when detecting the pulse laser. Further, it is difficult to separately measure only the absorption amount by an optical method, and it is always detected as a value including the scattering amount on the surface or the like. Therefore, some methods of measuring a minute amount of light absorption, which do not rely on the conventional optical method, have been proposed and implemented. Most of them are methods of measuring absorption of light as heat which is a non-radiative transition.

A typical method is known as calorimetry, in which the temperature rise due to light absorption of the sample is directly measured by a temperature measuring means such as a thermocouple. Further, there is also a photoacoustic measurement method in which an acoustic signal generated by deformation and (releasing) deformation of a sample or an atmosphere in the vicinity of the sample due to a temperature rise is detected, and the light absorption amount is calculated back from the acoustic signal.

More recently, a method of detecting the refractive index distribution and displacement of the sample or its vicinity caused by absorption heating by light (deflection of light beam, detection of optical path difference, etc.) has been actively used. Among them, the photoacoustic measurement method for performing acoustic measurement (hereinafter, sometimes abbreviated as photoacoustic method) is relatively easy to perform and has high measurement sensitivity.
Widely tried for thin film materials.

In this method, in a sample or an atmosphere in the vicinity thereof, sound that is a volume change caused by heating and cooling by irradiation of intermittent light is converted into an electric signal by a microphone or a piezoelectric element transducer attached to the sample or sample holder. To detect. By analyzing the intensity or phase of the electric signal, various information regarding the non-radiative transition of the substance can be obtained, but the magnitude of the acoustic wave is usually proportional to the thermal energy (that is, the amount of light absorption) ( Detailed theory can be found in the paper J.Appl.Phys, v
ol.47, No1, pp64. J.Appl.Phys, vol.51, No6, pp3343.
Can.J.Phys, vol.64, pp147 etc.), and the amount of light absorption can be calculated from here.

According to this method, even if the absorption is minute, the amount of detection signal can be increased by using the one having high light intensity, and the measurement can be performed with high sensitivity. The photoacoustic method is used as an analytical method such as an analysis of a non-radiative transition process of a substance, and has been attracting attention as a method of measuring a light absorption amount in terms of its sensitivity and ease of measurement.

[0009]

One of the major problems in measuring the amount of light absorption by the photoacoustic method is the dependence of the signal intensity on the acoustic wave propagation conditions. Since the intensity of the acoustic wave changes depending on the acoustic wave propagation condition from the absorption site, even if the light irradiation condition to the sample is the same, the distance between the sample (and the sound source that is the light irradiation part) and the acoustic sensing element It depends on the acoustic joining conditions. Therefore, care must be taken when comparing signal strengths between separate samples.

In the telemetry using the microphone, the reproducibility of the sound propagation from the sample is relatively easy to obtain and the standardization of the signal is easy. Also, in the case of measurement with liquid samples and gas samples, with the cell that encloses them,
By keeping the setting of the light source light (measurement light) and the acoustic detection element constant, it is possible to obtain reproducibility of the signal intensity.

However, in the measurement of a solid sample such as a thin film sample formed on a glass substrate, it is not easy to keep the acoustic propagation condition constant when trying to detect a contact type acoustic with a large signal intensity. There is a problem. Here, what is particularly important is the contact condition of the contact portion between the solid sample and the acoustic detection element or the sample holder, and when the sound propagation condition (that is, contact condition) at the contact portion is different when the sample is exchanged. However, there is a problem that the signal strength changes.

For example, when the solid sample and the sample holder (or the acoustic detecting element) are brought into contact with each other by directly pressing them, the sample and the holder (or the acoustic detecting element) are generally rigid solids. Therefore, a slight void layer is formed due to unevenness (or dirt) on the surface. Therefore, it has been confirmed that it is difficult to keep the acoustic contact condition constant, and there is a problem in that the signal strength largely deviates (disperses) and the reliability of measurement decreases.

Further, when the two are contacted with each other by grease or the like which is often used as an acoustic matching material, the thickness of the matching material layer and the contact state with the sample change unless the pressing is carefully performed, resulting in a large acoustic intensity. There is a problem in that there are many deviations (variations), and as a result, the reliability of measurement is reduced. There are other problems when using grease or the like. That is, in this case, since grease or the like adheres to the sample or the holder at the time of setting the sample, it is necessary to wash the sample or the holder and apply (supplement) the matching material every time the sample is exchanged, and the measurement efficiency is improved. There is a problem that it decreases.

Therefore, as a method of solving these problems, a method of placing a sample in a liquid and measuring the sound propagating in the liquid has been proposed, and it is said that the measurement sensitivity is also improved ( Appl.Opt, vol.20, No.4, pp606). However, in such a conventional method, because of the arrangement, the sample is completely immersed in the liquid, so that the arrangement is such that the measurement light passes through the liquid, and the measurement is very difficult unless the liquid transmits almost all the measurement light. It has a problem that it is difficult.

In particular, in the case of measurement with light having a wavelength in the ultraviolet region, there is a problem that the existence of a liquid that transmits almost all the measurement light is rare and is not general. Further, even when there is a liquid that transmits almost all the measurement light, it is necessary to consider the optical properties of the liquid (absorption, reflection, scattering, etc.), which is troublesome when evaluating the detection value. There is a problem that accuracy may be reduced.

The present invention has been made in view of the above problems, and it is possible to easily maintain a constant acoustic contact condition with a measurement sample, and as a result, the reliability and efficiency of measurement can be improved. It is an object of the present invention to provide a light absorption measuring device that can be improved.

[0017]

Therefore, in the first aspect of the present invention, "the light absorption of the sample is measured by measuring the acoustic signal generated by the volume change of the sample caused by the light absorption when the sample is irradiated with light. In a light absorption measuring device for measuring, a sample holder for holding the sample, configured and / or arranged so as not to block the optical path of the irradiation light, and a part of the sample stored and held. A sample holder having a holding portion filled with a liquid, a liquid supply mechanism for supplying the liquid to the holding portion, a liquid storage portion for storing an unnecessary liquid among the liquids supplied to the holding portion, An optical absorption measuring device (claim 1) "is provided.

The second aspect of the present invention is that the "liquid supply mechanism is also a liquid replenishment mechanism for replenishing the liquid so that the amount of the liquid filled in the holding portion is always constant or substantially constant. An optical absorption measuring device according to claim 1 is provided. In addition, a third aspect of the present invention is that "the liquid supply mechanism is provided with a liquid recovery mechanism for recovering the liquid stored in the liquid storage portion so that the recovered liquid can be supplied to the holding portion. An optical absorption measuring device according to claim 2 is provided.

A fourth aspect of the present invention provides an "optical absorption measuring device (claim 4), characterized in that a liquid temperature control mechanism for controlling the temperature of the liquid is provided." To do.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An optical absorption measuring device (one example) according to the present invention will be described with reference to the drawings, but the present invention is not limited to the examples of the drawings. The optical absorption measuring device illustrated in FIG. 4 is a system in which light from a light source is condensed by various optical systems and is irradiated on a sample. When irradiating, change the light amount (irradiation light intensity) with an appropriate light amount adjustment part, monitor the light amount (irradiation light intensity) in the branch optical path, and calculate the light absorption amount from the correlation between the irradiation light intensity and the acoustic signal. It is a system that does.

In the example of FIG. 4, the measurement sample 20 is a thin film formed on a glass substrate. Both the material and size of the substrate are constant, and the substrate surface is sufficiently smooth. The amount by which the substrate absorbs the measurement light is preferably sufficiently smaller than the amount by which the thin film to be measured absorbs the measurement light. In this example, a circular pellet-shaped glass substrate is used. In order to realize the configuration described in claim 1, for example, the sample holder 1, the liquid supply mechanism 7, and the liquid container 2 as shown in FIG. 1 are used.

As shown in FIG. 1, the sample holder 1 is provided with an arcuate groove (an example of a holding portion) H. When the sample 3 is set in the groove, the upper part of the sample 3 comes out of the holder 1. , Groove H is formed. Also, the groove H
A liquid (matching material) 4 is injected into the liquid by a liquid supply mechanism 7 to fill the gap between the sample 3 and the groove H. The liquid 4 has a specific gravity such that the sample does not float. In addition, the measurement light is applied to a portion of the sample 3 that is not immersed in the liquid 4 (a spot 8 is formed).

In this example, the width of the sample 3 and the width of the groove H are the same, and the sample 3 does not move in the groove H and is always arranged at a fixed position. Since the sample holder used in the optical absorption measuring device of the present invention has such a configuration, the voids that are generally problematic in contact pressure bonding of solids are eliminated by passing the liquid, and the acoustic impedance is matched. Is improved, the intensity of the detection signal is increased, and the reproducibility of the acoustic propagation condition is improved.

That is, the sample holder according to the present invention can easily keep the acoustic contact condition with the solid sample constant, and as a result, the reliability and efficiency of the measurement can be improved. Further, the sample holder according to the present invention is configured (arranged) so that the measurement light 6 does not pass through the sample holder 1 and the liquid 4.
The measurement using the sample holder 1 has a great advantage that it is not necessary to particularly consider the limitation due to the optical characteristics of the liquid 4 and the constituent members of the sample holder 1.

There is also known a method in which a liquid such as water is sandwiched between the acoustic detection element and the sample to form a thin layer for matching (Appl.Phys.Lett, vol.45, No.5 pp5.
10. etc.), this method is very cumbersome to set up, and requires extra liquid treatment after setting.
On the other hand, in the measurement using the sample holder 1 according to the present invention, the sample 3 is placed in a predetermined amount of the liquid 4.
It has a great advantage that setting can be completed simply by inserting.

In order to maintain the acoustic reproducibility, the amount of the liquid 4 filled in the holding portion H of the holder 1 is preferably constant. Therefore, for example, before installing (setting) the sample 3 in the holder 1, a certain amount of the liquid 4 is put in the holding portion H of the holder 1 by using the liquid supply mechanism 7, and then the sample 3 is set in the holder 1. It may be set in the holding portion H. Alternatively, after setting the sample 3 in the holder 1, a fixed amount of the liquid 4 may be injected into the holding portion H using the liquid supply mechanism 7.

As the liquid supply mechanism 7, for example, the syringe shown in FIG. 1 can be used, but it is not limited to this (other examples will be described later). The syringe can finely control the amount of liquid to be supplied, and also has a function of removing it when the amount of liquid to be supplied is too large. In any case, for example, by marking the holder 1 to monitor the liquid amount, it is possible to perform measurement with a constant liquid amount.

However, in this method, it is necessary to completely remove the liquid and fill a fixed amount of the liquid each time the sample is exchanged, which makes the operation complicated. Further, even if the amount of the supply liquid or the amount of the removal liquid can be finely controlled by using the syringe, if the liquid has a low viscosity, the operation becomes difficult due to the influence of dripping and capillarity. Therefore, in the measurement according to the present invention, in order to easily keep the amount of the liquid 4 filled in the holding portion H of the holder 1 constant, the liquid supply mechanism 7 supplies more liquid than the liquid amount at which the holding portion H is full. The unnecessary (excessive) liquid 10 of the supplied liquid is naturally stored in the liquid storage portion 2.

In order to naturally store the unnecessary (excess) liquid 10 in the liquid storage portion 2, for example, as shown in FIG. 1, the unnecessary (excess) liquid 10 is naturally discharged from the holding portion H of the holder 1. The overflowing liquid 10 may be stored in the liquid storage portion 2 provided on the wall surface of the holder 1. Liquid container 2
The unnecessary (excessive) liquid 10 stored in 1 is preferably collected in another container in a timely or continuous manner because the liquid storage portion 2 can be prevented from being filled with the liquid 10.

If the unnecessary (excessive) liquid 10 is simply overflowed from the holding portion H of the holder 1, the overflowed liquid remains attached to various places, so that the performance of the measuring device is deteriorated due to contamination, the environment is deteriorated, and the liquid is Problems such as waste of money will occur,
In the measurement according to the present invention, since the overflowed liquid is stored in the liquid storage portion 2, the above problem does not occur. In addition,
Even when the overflowed liquid is stored in the liquid storage portion 2, the liquid adheres to a part of the wall surface of the holder 1, but the sample 3
We have confirmed that it does not affect the measurement part of the and does not affect the acoustic signal.

Liquid 1 attached to a part of the wall surface of holder 1
0 may be wiped off at appropriate times, but when the liquid is a liquid that easily volatilizes, it does not need to be wiped off because it volatilizes naturally after attachment. In the optical absorption measurement according to the present invention, the property of liquid is also a problem. For example, when a highly viscous liquid is used, bubbles may be generated in the liquid, which has a great influence on sound propagation. Therefore, it is preferable that the liquid filled in the holding portion does not contain bubbles.

We have observed that the reproducibility of the signal intensity cannot be obtained when air bubbles are present even when water is used. Therefore, as the liquid, a low-viscosity liquid that is less likely to generate bubbles inside is preferable as it eliminates the trouble of seeing bubbles when setting the sample. By the way, even if the holding part H is first filled with a certain amount of liquid 4, for example, when the sample is replaced or when the liquid having high volatility is used during measurement, the liquid 4 in the holding part H is slightly Since it decreases, it is preferable to control so that the amount of the liquid filled in the holding portion H is always constant or substantially constant during measurement.

Therefore, it is preferable that the liquid supply mechanism according to the present invention is also a liquid replenishment mechanism that replenishes the liquid so that the amount of the liquid filled in the holding portion is constantly or substantially constant during measurement ( Claim 2). As such a mechanism,
For example, there are a flow-in mechanism using gravity, a siphon mechanism, a flow-in mechanism by applying pressure, but the flow mechanism is not limited to this.

When the liquid is supplied (filled or replenished) to the holding portion, the flow velocity and flow rate are such that no bubbles are generated due to the flow of the liquid or a large undulation of the liquid surface, which is a factor that hinders acoustic propagation. It is preferable to supply by the route. In order to effectively use the liquid or to further prevent environmental deterioration and device performance deterioration, the liquid supply mechanism according to the present invention is provided with a liquid recovery mechanism for recovering the liquid contained in the liquid container. ,
It is preferable that the recovered liquid can be supplied to the holding unit (claim 3).

Since the acoustic propagation characteristic changes depending on the temperature of the substance, it is preferable to keep the temperature of the measuring system as constant as possible in order to perform accurate measurement. Therefore, it is preferable to provide a liquid temperature control mechanism for controlling the temperature of the liquid (claim 4). The detection of the acoustic signal according to the present invention is performed by a piezoelectric element (an example of an acoustic detection element) 6 attached to the sample holder 1 as shown in FIG. 1, for example.

The piezoelectric element 6 of this example is firmly fixed to the holder 1 with an adhesive or the like. As a result, the piezoelectric element 6 and the holder 1 are stably acoustically matched, and the measurement reliability is improved. That is, in order to improve the reliability of measurement,
It is preferable that the sample holder is provided with an acoustic sensing element in an acoustically matched state.

There is a problem of noise as an important item to be taken into consideration when performing the light absorption measurement, and in the measurement by the photoacoustic method according to the present invention, particularly scattered light of light incident on the sample or stray light from the optical system is detected. It is preferable to take care that does not affect the measurement. These effects can be suppressed to some extent by devising the optical system and selecting the time region for signal detection. Of these, the effects of acoustic waves caused by absorption of scattered light and stray light by the holder are excluded. For that purpose, it is preferable to configure the holder by using a material that does not absorb the light of the measurement wavelength as much as possible, that is, transmits or reflects.

Therefore, the constituent members of the sample holder have a loss of 0.1% corresponding to absorption and scattering of irradiation light.
It is preferable to use the following materials. Furthermore, it is preferable that the constituent members of the sample holder be subjected to a treatment for preventing reflection of irradiation light. As such processing,
For example, there is an antireflection coat formed by laminating a thin film on a member.

In order to improve the reproducibility of the optical absorption measurement according to the present invention, it is preferable to keep the position of the sample in the holder constant. Therefore, it is preferable to provide a sample positioning mechanism on the sample holder. For example,
By supporting the surface direction of the sample 20 so as to be in contact with the V-shaped bottom surface of the groove H, and by adjusting the width direction of the sample 20 to the width of the groove H in the width direction of the sample 20, the sample 20 is kept at a fixed position. Retained.

Further, the sample may be positioned in the groove width direction by providing a notch serving as a guide on the bottom surface of the groove H. In addition to this, for example, a mechanism for pressing and fixing the sample may be used. In this mechanism, screws 36, spacers 37, springs, etc. are generally used (one example is shown in FIG. 5). It is preferable that the sample pressing screw (an example of a sample positioning mechanism) 36 is not arranged on the optical path and is always pressed at the same position.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0042]

[Embodiment 1] FIG. 4 is a schematic configuration diagram of a light absorption measuring apparatus of this embodiment, and photoacoustic measurement was performed using this apparatus.
The light source is an ArF excimer laser (wavelength 193 nm) 13 with a pulse width of about 20 nsec. The pulse irradiation (measurement) light passes through the lens optical system 14 and is condensed by the objective lens 16 to be irradiated on the sample 20 in the sample holder 21 fixed to the optical holder, and the light diameter on the sample surface is about 3 mmΦ. Is.

The intensity of the irradiation light is adjusted by the zoom lens inserted in the optical system 14, and the intensity of the irradiation light is
An optical sensor (biplanar type photomultiplier) 18 monitors in a branched optical path using reflection of quartz glass 15 as shown in the figure. The light transmitted through the sample 20 is blocked by the absorber 17 to prevent the return. In addition, it is preferable that the absorber 17 is made of a material such as an elastic body that hardly transmits sound. In addition to providing the absorber 17, deflecting the optical path many times is also effective in preventing the return.

Since the irradiation light is absorbed by ozone generated in oxygen, the optical system is arranged in the nitrogen-purged chamber 19. Sample holder 21
5 is an aluminum holder provided with a groove H (an example of a holding portion) having a V-shaped bottom surface, as shown in FIG. The acoustic signal was detected by a sensor 22 having a structure in which a receiving plate made of alumina was attached to PZT (lead zirconate titanate) which is a piezoelectric material. The sensor (an example of an acoustic detection element) 22 is
It was fixed to the holder 21 using a heat-sensitive adhesive material 35.

As shown in FIG. 5, the holder 21 is sandwiched by the optical holder 32 via the rubber plate 31 and is fixed by a cap screw. It is fixed by the rubber plate 31 which is an elastic body in order to acoustically separate from the optical holder 32 and the like as much as possible (to reduce the influence as noise in acoustic detection). Sample 20 is 30mmΦ and thickness 2
A thin film having a thickness of 1 μm or less is formed on a quartz glass substrate (transmission of light having a measurement wavelength) in the form of a circular pellet of mm, and a groove (an example of a holding portion) H having a V-shaped bottom surface of the holder 21 is formed. It is set and fixed in a fixed position by being sandwiched between the screw 36 and the spacer 37 provided on one wall.

In the gap between the groove H and the sample 20, Isopar (trade name, matching material manufactured by Esso Co.) 26, which is an insulating solvent, overflows from the edge of the groove H by a syringe (an example of a liquid supply mechanism) 29. Is injected up to. Isopar, which is used as a solvent for liquid ink, is a liquid that has low viscosity, is less likely to generate bubbles, and has low volatility.

The overflowed liquid descends along the wall of the holder 21 and is contained in a liquid reservoir container (an example of a liquid container) 27 provided on the front wall of the holder 21. The holder 21
Since the front wall is lower in height than the rear wall, the liquid 26 overflows only from the front wall side (34). The sample 20 set in this manner is irradiated with light while changing the light intensity by driving the zoom lens of the optical system 14.
The output (voltage) of the light amount monitor sensor 18 is measured.

Photoacoustic signal generation by absorption of the sample is
It is about 15 μsec after irradiation. The signal immediately after irradiation or some time after the arrival of sound is a noise signal other than the optical absorption of the sample, so about 10 μs
The measurement was performed by taking in the signal of ec. The signal is appropriately filtered to remove noise. In this example, the main frequency of sound is about 150 kHz,
The wavelength around this was selected and measured (by FFT23).

The acoustic signal and the light intensity signal are measured and recorded for each pulse irradiation in cooperation with the computer 24 controlling the zoom lens. Measurement result, liquid 2
Even if 6 descends along the front wall of the holder 21 and the descended liquid 28 is contained in the liquid reservoir 27, the amount of liquid in the holder H of the holder does not change, so the photoacoustic signal changes. There wasn't. Also, good reproducibility of the measurement was observed even if the sample was replaced.

During the measurement, the syringe 29 was used to replenish the liquid at appropriate times so that the amount of liquid in the holding portion H did not decrease. Further, the liquid 28 contained in the liquid sump container 27 was collected at an appropriate time using a syringe 30. Therefore, most of the overflowed liquid was not collected and the hands and the measuring device were not contaminated. Therefore, in this embodiment, a great effect was obtained in effective use of the liquid and prevention of environmental deterioration and device performance deterioration.

[0051]

[Embodiment 2] In the present embodiment, a liquid matching material (methyl alcohol) is supplied from a liquid supply container (an example of a liquid supply mechanism and a liquid supply mechanism) 38 equipped with a liquid supply thin tube 39 and a valve 40.
Was filled in the holder H of the holder, and the same measurement apparatus as in Example 1 was used to perform the same measurement as in Example 1 except that the holder H was continuously replenished with liquid during the measurement.

The valve 4 is used for filling and replenishing the liquid.
The flow rate was controlled by conductance control in the middle of the liquid supply thin tube 39 using 0, and attention was paid so that the liquid flow did not generate bubbles. In the present embodiment, it is possible to continuously replenish the holding portion H with liquid during the measurement, and even if methyl alcohol, which has a large volatility and thus easily reduces the amount of liquid, is used, The photoacoustic signal did not show any change because the liquid volume did not change. Also, good reproducibility of the measurement was observed even if the sample was replaced.

During the sample exchange, the liquid supply could be stopped by closing the valve 40.
Further, since the measurement sample and the methyl alcohol attached to the front wall of the holder were immediately volatilized, it was not necessary to wipe them off.

[0054]

Third Embodiment In this embodiment, a liquid supply container (an example of a liquid supply mechanism and a liquid replenishing mechanism) 38 equipped with a liquid supply thin tube 39 and a valve 40 is contained in a liquid sump container (an example of a liquid container) 27. A liquid recovery mechanism for recovering the recovered liquid is provided so that the recovered liquid can be supplied to the holder H of the holder, and a lid 44 is provided on the liquid supply container 38 to reduce exposure to the atmosphere and close to a hermetic seal. The same measurement as in Example 2 was performed by using the same measuring apparatus as in Example 2 except that the state was set.

The liquid recovery mechanism includes a pump 42, and each pipe 4 connecting the pump to the liquid sump container 27 and the liquid supply container 38.
1 and 43. In the present embodiment, fully automatic liquid supply (filling / replenishment) and circulation are possible, and further effects are obtained in effective use of liquid and prevention of environmental deterioration and device performance deterioration.

[0056]

As described above, according to the optical absorption measuring apparatus of the present invention, it is possible to easily keep the acoustic contact condition with the measurement sample constant, and as a result, the reliability of the measurement and the reliability of the measurement can be improved. The efficiency can be improved. Further, according to the optical absorption measuring device of the present invention, a great effect can be obtained in effective use of the liquid matching material used for measurement and prevention of environmental deterioration and device performance deterioration.

[Brief description of the drawings]

FIG. 1 is a schematic front view (partial cross-sectional view, (a)) and schematic cross-sectional view (b) showing an example of a sample holder 1, a liquid storage unit 2, a liquid supply mechanism 7, etc. according to the present invention. .

FIG. 2 is a schematic cross-sectional view showing another example of the sample holder 1, the liquid container 2, the liquid supply mechanism 11 and the like according to the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of the sample holder 1, the liquid container 2, the liquid supply mechanism 11, the liquid recovery mechanism 12, etc. according to the present invention.

FIG. 4 is a schematic device configuration diagram showing an example of a light absorption measuring device of the present invention.

FIG. 5 is a schematic sectional view (a) showing a part of the measurement system of Example 1, a schematic front view (partial sectional view, (b)), a schematic rear view (partial sectional view, (c)). ).

FIG. 6 is a schematic configuration diagram showing a part of a measurement system of Example 2.

FIG. 7 is a schematic configuration diagram showing a part of a measurement system of Example 3.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample holder 2 ... Liquid storage container (an example of liquid storage part) 3 ... Measurement sample 4 ... Liquid (matching material) 5 ... It is stored in a liquid storage container (liquid storage part) Liquid (matching material) 6 ... Acoustic sensing element 7 ... Syringe (an example of liquid supply mechanism) 8 ... Measuring light spot 9 ... Measuring light 10 ... Representing overflowing liquid (matching material) . 11. Continuous liquid supply mechanism (an example of liquid supply mechanism) 12. Liquid recovery mechanism 13. ArF excimer laser 14. Light intensity adjustment optical system (including zoom lens) 15. Quartz glass plate 16. Objective Lens 17 ・ Light block absorber 18 ・ Light intensity monitor sensor 19 ・ Chamber 20 ・ ・ Measurement sample 21 ・ ・ Sample holder 22 ・ ・ PZT piezoelectric element with alumina receiving plate (an example of acoustic detection element) 23 ・ ・ Amplifier, Frequency selection device (filter, FFT) 24..Personal computer 25 .. 26 .. Isopar (an example of liquid matching material) 27 .. Liquid reservoir (an example of liquid storage part) 28 .. Liquid (matching material) contained in a liquid reservoir (liquid storage part) 29 .. Syringe (liquid) An example of supply mechanism 30 .. Syringe (for liquid recovery) 31 .. Rubber plate 32 .. Optical holder 33 .. Laser beam (measuring light) 34 .. Representing overflowing liquid (matching material) 35 .. Adhesive 36 .. Retaining screw 37 .. Spacer 38 .. Liquid supply container 39 .. Liquid supply thin tube 40 .. Valve 41 .. Piping to pump 42 .. Pump 43 .. Piping to liquid supply container 44 .. Liquid supply Lid of container H ... Above holding part

Claims (4)

[Claims] 1. A light absorption measuring device for measuring the light absorption of a sample by measuring an acoustic signal generated by a volume change of the sample caused by light absorption when the sample is irradiated with light. A sample holder that is configured and / or arranged so as not to block the optical path of irradiation light, and that has a liquid-filled holding portion that holds and holds a part of the sample. And a liquid supply mechanism that supplies the liquid to the holding unit, and a liquid storage unit that stores an unnecessary liquid of the liquid supplied to the holding unit. 2. The liquid supply mechanism is also a liquid replenishment mechanism for replenishing the liquid so that the amount of the liquid filled in the holding portion is always constant or substantially constant. Optical absorption measuring device. 3. The liquid supply mechanism is provided with a liquid recovery mechanism for recovering the liquid stored in the liquid storage portion, so that the recovered liquid can be supplied to the holding portion. 2. The light absorption measuring device described in 2. 4. The optical absorption measuring device according to claim 1, further comprising a liquid temperature control mechanism for controlling the temperature of the liquid.