JP3101638B2 - High temperature observation and thermal expansion simultaneous measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature observation / thermal expansion simultaneous measurement apparatus used for firing and sintering various materials, especially electronic materials.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 1-163594 discloses a high-temperature observation furnace using infrared image heating as one of the conventional heating devices for a high-temperature microscope. In this high-temperature observation furnace,
The inside of the furnace is partitioned into a light source chamber and a heating chamber by a transparent partitioning quartz plate, and the heating chamber has an airtight structure, and the transparent partitioning quartz plate is placed at a position where infrared density from an infrared light source in the light source chamber is low. An observation window is provided in the furnace wall portion which is positioned and passes through the optical axis of the objective lens of the microscope. Then, a change in the state or a change in the chemical of the substance is observed using a microscope while changing the temperature and the atmosphere. In a heating device for such a high-temperature microscope, when the temperature of the sample changes due to heating and thermal expansion or contraction occurs, the observation surface moves, and as a result, the objective lens of the microscope shifts and the CCD camera becomes out of focus. The image obtained by the video electric signal is blurred. In addition, in the firing and sintering of materials, it is often necessary to observe information on state changes and chemical changes, as well as information on changes in dimensions in the depth direction. Like the rate measurement, the rate of change measurement is limited to 0.1% (10 ^-3 ).
For this reason, in general, a push rod type for measuring the thermal expansion by bringing a detection rod into contact with a measurement sample is used for the thermal expansion measurement. In this push rod type, one end of the sample is fixed on a support table, a push rod is applied to the other end, the tip of the push rod is extended out of the furnace, and a reference rod of the same material as the push rod is supported. The tip of the reference rod is extended outside the furnace as a reference position for displacement, and the coefficient of thermal expansion of the sample is measured from the difference between the measured position of the tip of the push rod and the reference position of the tip of the reference rod. Has been. Other conventional methods for measuring thermal expansion include direct-view methods, X-ray diffraction methods, optical interferometry, and capacitance methods as methods for directly measuring changes in sample length. Is directly measured, the position detection accuracy is not very good, and the limit is about 1 μm. X-ray diffraction is
X-ray diffraction is performed while heating the sample to determine the lattice constant. In the optical interference method, monochromatic parallel rays are projected onto the sample or an interference plate such as a quartz plate sandwiching the sample, so that both ends of the sample are exposed. The interference fringes generated by the phase difference of the light reflected by the interference plates are observed, and the thickness and length of the sample are measured from the intervals. The capacitance method is used in a low temperature range and detects displacement of a sample as a change in capacitance. The capacitance method has a high resolution and a measurement sensitivity up to about 10 ⁻¹⁴ m.

[0003]

By the way, in the push rod type conventionally used for the measurement of the rate of change such as the measurement of the coefficient of thermal expansion, the accuracy depends on the accuracy of the reference rod. In addition, not only the thermal expansion of the detection rod itself affects the measurement, but also a problem such as a measurement pressure. In particular, in a molten state such as glass, it is necessary to perform measurement without contact. Also, in the prior art, the observation of the state change or chemical change and the measurement of the change rate are performed using separate devices, respectively, so that the same sample required under melting and sintering under the same conditions is used. Observation of a state change or a chemical change and measurement of a change rate cannot be performed simultaneously. By the way, a recent microscope equipped with an automatic focus adjustment mechanism for automatic observation of a semiconductor device or the like is known.

In order to solve the above problem, the present invention provides an automatic focus adjusting mechanism in a high-temperature microscope, utilizing the fact that the focal point shift of the automatic focus adjusting mechanism is proportional to the thermal expansion or contraction of the sample. It is an issue to be solved to measure the change rate at the same time. Accordingly, an object of the present invention is to provide a high-temperature observation / thermal expansion simultaneous measurement apparatus which can measure the thermal expansion and contraction of a sample at the same time as high-temperature observation by using the focus movement amount of an automatic focus adjustment mechanism in a high-temperature microscope. It is in.

[0005]

In order to achieve the above object, a high-temperature observation / thermal expansion simultaneous measuring apparatus according to the present invention comprises a furnace formed adjacent to an objective lens of a microscope and surrounding its optical axis. The inside is divided into a light source chamber and a heating chamber by a transparent partitioning quartz plate, the heating chamber is made airtight, and a hole for passing a sample support rod is provided in the quartz plate portion where the optical axis of the objective lens of the microscope passes, The sample is held in the heating chamber by the sample support rod from below through this hole, an observation window is provided in the furnace wall portion where the optical axis of the microscope objective lens passes, and the microscope objective is set according to the expansion and contraction due to the temperature change of the sample. It is characterized in that a focus adjusting device for adjusting the focus shift of the lens is provided, and a device for detecting thermal expansion and contraction of the sample based on the amount of focus movement by the focus adjusting device is further provided. In the apparatus according to the present invention, the apparatus for detecting thermal expansion and contraction of the sample based on the amount of focus movement by the focus adjustment device is a conversion circuit and a display device in the focus adjustment device that converts the amount of focus movement by the focus adjustment device into a digital signal. Can consist of

[0006]

In the apparatus according to the present invention thus constructed, the sample is positioned on the optical axis of the objective lens of the microscope and is supported by the sample support rod. Thus, the upper surface of the sample facing the objective lens of the microscope, that is, the observation surface moves due to thermal expansion or contraction due to heating. The focus adjustment device provided in the microscope adjusts the focus in accordance with the movement of the observation surface, so that the observation surface of the sample can be always observed in focus. On the other hand, the amount of movement of the focal point by the focus adjustment device is equivalent to the amount of movement of the observation surface of the sample due to thermal expansion or contraction. Can be detected simultaneously.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows an example of a high-temperature observation furnace using infrared image heating used in the apparatus of the present invention, 1 is a furnace main body, and the furnace main body 1 can be made of, for example, aluminum. Is provided with a rotatable furnace chamber 2 which passes through one focal point of the ellipse and is obtained using a line intersecting the long axis of the ellipse as a rotation axis, and its inner wall is plated with gold. Furnace body 1 is provided with cooling medium passages 3 and 4 surrounding furnace chamber 2, and these cooling medium passages 3 and 4 are connected to a suitable cooling medium supply source (not shown), and To cool. The central portion of the upper wall of the furnace chamber 2 is formed in a planar shape, and an observation window 6 made of quartz is hermetically attached to the center opening 5 from the outside by a mounting member 7, and the observation window 6 is as shown in the figure. The lens is positioned so as to be rotatable in opposition to the objective lens 8 of the microscope and eccentric to the optical axis of the microscope. An opening 9 extending to the outside is provided in a central portion of the lower wall opposite to the central opening 5 in the central portion of the upper wall. A ring-shaped infrared light source 10 is arranged in the lower part of the furnace chamber 2 on the locus drawn by the other focal point of the ellipse. The infrared light source 10 is energized from the outside and is reflected directly or on the inner wall of the furnace chamber 2. Then, infrared rays are incident from all directions toward a sample described later.

Immediately above the infrared light source 10, a transparent partitioning quartz plate 11 is inserted perpendicular to the optical axis of the microscope, and the furnace room 2 is divided into a light source room 2a in which the infrared light source 10 is disposed and a heating chamber above. 2b. In this case, the partitioning quartz plate 11 can be preferably positioned at a position where the density of infrared light from the infrared light source 10 is low. A sample insertion opening 12 is provided at the center of the partitioning quartz plate 11, and a quartz cylindrical extension 13 extending from the edge of the opening 12 along the inner wall of the opening 9 provided at the center of the lower wall. It is formed integrally. This cylindrical extension
A vacuum seal is provided between 13 and the inner wall of the opening 9 as shown. In addition, the quartz plate for partition 11 is of course a heating chamber 2b.
Is configured to withstand a differential pressure that may occur when evacuation is performed. In addition, a cylindrical extension 13 at the center of the quartz plate 11 for partitioning.
A sample support rod 14 is passed through the sample support rod 14. The sample support rod 14 is made of a material having low thermal expansion and low thermal conductivity, for example, transparent quartz.
The mounting block 15 is mounted on the outer bottom surface of the furnace body 1 via a vacuum seal. Further, although not shown in the drawing, a gas inlet for filling a required gas into the heating chamber 2b is provided on the outside so as to communicate with the inside of the cylindrical extension portion 13. The sample support rod 14 holds the sample 16 to be observed at the tip thereof, and passes through the inside of the cylindrical extension 13 to heat the heating chamber 2b.
It can be inserted into the inside or pulled out of the heating chamber 2b. When the sample support rod 14 is inserted into the heating chamber 2b, the sample 16 is positioned on the optical axis of the microscope, and is not heated except in the vicinity of the sample 16. A thermocouple 17 for temperature measurement is mounted in the sample support rod 14, and the thermocouple 17 measures the temperature of the sample 16, and its output signal is sent to a programmable temperature indicating controller 21 shown in FIG. It can be used to control the activation of the infrared light source 10 in the light source chamber 2a via the SCR output unit indicated by reference numeral 24 in FIG. In FIG. 1, reference numeral 18 denotes a vacuum exhaust passage for evacuating the heating chamber 2b.

FIG. 2 schematically shows the entire configuration of an apparatus according to an embodiment of the present invention. Reference numeral 22 is connected to the output of a programmable temperature indicating controller 21, and includes a cursor line generating circuit, a character converting circuit, and a spur impose. The circuit device is composed of a circuit, and a color monitor 23 is connected to an output of the circuit device. 25 is a CCD video camera controller, 26 is an automatic focus adjustment device, 27 is a high-temperature microscope for observation, and 28 is a heating furnace shown in FIG. The CCD video camera controller 25 is incorporated in the high-temperature microscope 27 and supplies an imaging signal of the observation surface of the sample 16 (see FIG. 1) in the heating furnace 28 observed by the high-temperature microscope 27 to the circuit device 22 and to the high-temperature microscope 27 The built-in automatic focus adjusting device 26 is supplied with a signal indicating a focus shift due to the movement of the observation surface to the automatic focus adjusting device 26 incorporated in the high-temperature microscope 27. The automatic focus adjustment device 26 automatically adjusts the focus adjustment knob of the high-temperature microscope 27 by, for example, a pulse motor or the like in accordance with the focus shift amount based on the signal indicating the defocus, and the observation surface of the sample is thermally expanded. The observation surface can always be observed in focus even if it moves due to contraction or shrinkage. Simultaneously with this observation, the focus movement amount ΔL obtained by the automatic focus adjustment device 26 is supplied to the circuit device 22, converted into a digital amount, and spur imposed with other digital measurement values, for example, temperature, time, etc. The thermal expansion and contraction amounts of the sample are displayed on the color monitor 23 forming a display device. In this case, sample 16
Is located along the optical axis of the high-temperature microscope 27, and the sample
Since the sample support rod 14 holding the sample 16 is made of a material having a small thermal expansion and is not heated except in the vicinity of the sample, a change in only the sample 16 can be detected. The thermal expansion of the sample,
To obtain a large amount of shrinkage, the length of the sample may be increased, but in this case, it is necessary to prevent the sample from shifting from the soaking zone.

[0010]

As described above, in the apparatus according to the present invention, a sample is placed on the optical axis of the microscope objective lens in a furnace formed adjacent to and surrounding the optical axis of the microscope objective lens. Hold the sample with a sample support rod, configure the microscope to observe the sample, provide a focus adjustment device to the microscope, and provide a device that detects the amount of focus movement by the focus adjustment device as the amount of thermal expansion and contraction of the sample. Therefore, it is not only possible to observe the state change and chemical change of the sample in a focused state at the same time, but at the same time, it is possible to obtain information such as a change in the depth dimension of the sample under the same conditions. Thus, it is possible to simultaneously observe state changes and chemical changes and measure physical changes of the same sample under the same conditions.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a high-temperature observation furnace which is a main part of the apparatus of the present invention.

FIG. 2 is a schematic block diagram showing a configuration of an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1: Furnace body 2: Furnace room 6: Observation window 8: Objective lens 9: Opening 10: Infrared light source 11: Quartz plate for partition 12: Sample insertion opening 13: Cylindrical extension 14: Sample support rod 16: Sample 17: Thermocouple 21: Programmable temperature indicating controller 22: Circuit device 23: Display device 25: CCD video camera controller 26: Automatic focus adjustment device 27: Microscope 28: Heating furnace

Claims (2)

(57) [Claims] 1. A furnace formed adjacent to an objective lens of a microscope and surrounding an optical axis thereof is partitioned into a light source chamber and a heating chamber by a transparent partitioning quartz plate, and the heating chamber has an airtight structure. A hole for passing a sample support rod is provided in a portion of the quartz plate through which the optical axis of the microscope objective lens passes, and the sample is held in the heating chamber by the sample support rod from below through the hole, and the sample passes through the optical axis of the microscope objective lens. An observation window is provided in the furnace wall, and a focus adjustment device is provided for adjusting the defocus of the objective lens of the microscope according to the expansion and contraction of the sample due to a change in temperature. A high-temperature observation / thermal expansion simultaneous measurement device, which is provided with a device for detecting thermal expansion and contraction. 2. An apparatus for detecting thermal expansion and contraction of a sample based on an amount of focus movement by a focus adjustment device, comprising a conversion circuit and a display device in a focus adjustment device for converting the amount of focus movement by the focus adjustment device into a digital signal. The simultaneous high temperature observation and thermal expansion measurement device according to claim 1.