JP4988459B2 - Constant temperature test equipment for testing and semiconductor wafer performance testing equipment - Google Patents

Description

  The present invention relates to a test thermostat, and more specifically, a test thermostat used for performance test of a semiconductor wafer on which a circuit is formed, and a semiconductor wafer performance test apparatus including the test thermostat. It is about.

  Electronic devices such as mobile phones and personal computers are widely used. These electronic devices are used in various applications and various environments in recent years. Therefore, it is necessary to test the influence received from the environment of the electronic device itself and the integrated circuit as these components. As a device for exposing these electronic components and the like to a high-temperature environment and a low-temperature environment, a thermostat for testing is used.

  The configuration of a general test thermostat is as shown in FIG. The test thermostat 51 shown in FIG. 9 includes a sample placement unit 52 and an electric heater 55. The sample placement portion 52 has a cylindrical shape, and the top surface thereof constitutes the sample placement surface 57. Further, a cavity 58 into which a heat medium is introduced is formed inside the sample placement unit 52. The electric heater 55 is for increasing the temperature of the sample placement surface 57 and is in contact with the bottom surface of the sample placement portion 52. Then, the control of the electric heater 55 and the operation of introducing the heat medium into the cavity 58 are used together to maintain the temperature of the sample mounting surface 57 at a desired temperature. For example, when the temperature of the sample mounting surface 57 is desired to be lowered, a low-temperature fluid is introduced into the cavity 58. In this way, it is possible to expose an electronic component or the like placed or fixed on the sample placement surface 57 to a high temperature environment or a low temperature environment.

As a test apparatus equipped with a constant temperature test apparatus, ones having structures disclosed in Patent Document 1 and Patent Document 2 are known. The test apparatus disclosed in Patent Documents 1 and 2 is an apparatus called a wafer prober, and includes a test thermostat called a thermal plate or a high / low temperature chuck, and a semiconductor wafer is mounted on the test thermostat. The test is performed by placing or fixing.
JP-A-2005-45039 Japanese Patent Laid-Open No. 10-288646

The test thermostat is used to perform a predetermined test by placing the integrated circuit on the sample mounting surface and changing the temperature of the integrated circuit, etc. However, the recent test conditions for the integrated circuit are severe. Therefore, a considerable temperature adjustment range is required for the test thermostat.
For example, the temperature may be repeatedly changed from a low temperature of about minus 65 degrees (Celsius) to a high temperature of about 300 degrees (Celsius).

As described above, recent test thermostats are required to have the ability to change the temperature from a very low temperature to a high temperature. However, if the temperature is adjusted to such a low temperature or high temperature, a sample of the test thermostat is used. There arises a problem that the arrangement portion is bent. That is, when the temperature of the test thermostat is adjusted to a very low temperature or a high temperature, the sample placement portion of the test thermostat may warp, dent, or twist.
Therefore, the present invention pays attention to this problem, and an object of the present invention is to provide a test thermostatic device in which the sample placement portion is less bent even if the temperature is adjusted to a very low temperature or a high temperature.

In order to solve the above-described problems, the present inventors have investigated the cause of bending of the sample placement portion. The reason why the sample placement part bends is of course due to expansion and contraction due to heat, but the reason why the sample placement part bends is that the fixing part with other members of the sample placement part cannot absorb expansion and contraction. It turned out.
That is, since the test thermostat is used by being incorporated in the semiconductor wafer performance test apparatus, the test thermostat is fixed at a predetermined position in the performance test apparatus. As described above, the test thermostatic device expands or contracts by being exposed to a severe temperature change.
On the other hand, since the performance test apparatus side is in a state close to room temperature, the fixed position of the test thermostat does not move (does not move).
Therefore, there is no escape space for expansion and contraction due to heat, and the test thermostat is warped, dented or twisted.

The invention completed based on these findings has a sample placement section and a gantry supporting the sample placement section, and the temperature of the sample placed in the sample placement section is adjusted by adjusting the temperature of the sample placement section. The sample placement unit has a sample placement surface on which a sample can be placed and a facing surface facing the sample placement surface, and the gantry includes the facing A connecting portion connected to the surface, the connecting portion is made of a material having the same coefficient of thermal expansion as the material of the sample placement portion, and the connection portion and the sample placement portion are connected to each other by a plurality of shafts. One of the axial fastening elements is arranged at the center of the circumscribed circle of the sample placement portion, and the other plurality of axial fastening elements are concentric with the circumscribed circle and smaller than the circumscribed circle. Axis on the circumference of the pitch circle A and provided on the pitch circle A Forming elements are arranged at equal intervals, the diameter of the pitch circle A is a test for thermostat, characterized in that less than one third of the diameter of the circumscribed circle of the sample placement part.

Among the above-described components, the shaft-like fastening element is, for example, a screw or a hook.
In the test thermostat of the present invention, the sample placement part is a part where the temperature changes. In the present invention, in the test thermostat, the connection part of the gantry is in contact with the sample placement part. The connecting portion is joined to the sample placement portion via a plurality of shaft-like fastening elements, but the joining position of both is arranged at the center of the circumscribed circle of the sample placement portion, and the other plurality of shaft-like fastening elements are A circle that is concentric with the circumscribed circle is on the circumference with the pitch circle A.
Here, the connection part changes its temperature by receiving heat conduction from the sample placement part, but the connection part adopted in the test thermostat is composed of the same material as the material of the sample placement part. The displacement of the connecting portion at the position where each on-axis fastening element is provided is equal to that on the testing thermostat side. That is, the sample placement part expands and contracts due to temperature changes, but when the center of the sample placement part is the origin, each part is displaced in the radial direction from the center. In the present invention, since one of the shaft-shaped fastening elements is arranged at the center of the circumscribed circle, when this point is taken as the origin, the position of the other shaft-shaped fastening element (the shaft-shaped fastening element provided around) is the origin. Is displaced in the radial direction around the center.
The same applies to the connecting portion, with one of the shaft-like fastening elements as the origin, and the positions of the other shaft-like fastening elements (shaft-like fastening elements provided around) are displaced in the radial direction around the origin.
And since the connection part is comprised with the raw material with the same thermal expansion coefficient as the material of a sample arrangement part as mentioned above, the displacement amount of the site | part of the axial fastening element provided in the circumference is equal to the thermostat for a test. . Therefore, no stress due to heat is generated in the shaft-like fastening element, and no excessive force is applied to the test thermostat.
Further, in the present invention, since the surrounding shaft-like fastening elements are arranged on the same pitch circle, the displacement amount of the position of each shaft-like fastening element is also the same, and since the balance is good, the test thermostat is further less distorted. .
The pitch circle axial fastening element is arranged, rather smaller than the circumscribed circle of the sample placement section, and the diameter of the pitch circle is less than one third of the diameter of the circumscribed circle of the sample placement part, a sample arrangement The amount of heat transferred from the part to the gantry side is small, and the thermal deformation of other parts is also small. Furthermore, since the amount of heat transferred from the sample placement portion to the gantry side is small, there is little waste of heat.

  The invention described in claim 2 is the thermostat for testing according to claim 1, wherein the circumscribed circle of the connecting portion of the gantry is smaller than the circumscribed circle of the sample placement portion.

  The circumscribed circle of the connecting portion of the gantry employed in the present invention is smaller than the circumscribed circle of the sample placement portion. Therefore, the amount of heat transferred from the sample placement part to the gantry side is small, and the thermal deformation of other parts is also small. Furthermore, since the amount of heat transferred from the sample placement portion to the gantry side is small, there is little waste of heat.

  According to a third aspect of the present invention, the gantry has a pedestal portion, and the pedestal portion is opposed to the facing surface of the sample placement portion, and the pedestal portion is projected onto the facing surface of the sample placement portion. 3. The test thermostat according to claim 1, wherein a region overlapping with the facing surface is assumed to be smaller than the facing surface when a projection region is assumed.

  The thermostat for testing of the present invention prevents the gantry from being deformed by heat radiation from the sample placement section. That is, in the test thermostat of the present invention, the pedestal portion of the gantry has a small area facing the facing surface of the sample placement portion. Therefore, the radiant heat received by the gantry is small, and the deformation of the gantry is small. Further, since the amount of heat transferred from the sample placement portion to the gantry side is small, there is little waste of heat.

  According to a fourth aspect of the present invention, the gantry includes a connection portion, a pedestal portion that is fixed to a predetermined installation surface, and an intermediate portion that is located between the connection portion and the pedestal portion. 4. The constant temperature test apparatus according to claim 1, wherein the thermal conductivity of the part is lower than the thermal conductivity of the connection part. 5.

  In this invention, a mount has a member with low heat conductivity in the intermediate part. Therefore, the heat received by the connecting portion is difficult to conduct to the pedestal portion side, and the deformation of the gantry is small. Further, since the amount of heat transferred from the sample placement portion to the gantry side is small, there is little waste of heat.

  In the invention according to claim 5, the connecting portion and the intermediate portion are connected by a shaft-like fastening element arranged on a predetermined pitch circle B, and the intermediate portion and the pedestal portion are arranged in a shaft shape arranged on the pitch circle C. The pitch circle B and the pitch circle C are connected by a fastening element, and the center and the diameter of the pitch circle B and the pitch circle C are the same, and the shaft-like fastening element that connects the connecting portion and the intermediate portion, and the shaft-like fastening element that connects the intermediate portion and the pedestal portion The thermostat for testing according to claim 4, wherein is at a position separated in the circumferential direction.

  In the test thermostat of the present invention, the pitch circle diameter of the fastening element that fixes the connecting portion and the intermediate portion and the pitch circle diameter of the fastening element that fixes the intermediate portion and the pedestal portion are the same. In addition, since the shaft-like fastening element that connects the connecting portion and the intermediate portion and the shaft-like fastening element that connects the intermediate portion and the pedestal portion are located in the circumferential direction, the thickness of the connecting portion and the intermediate portion is excessive. It will not be thick.

  In the invention described in claim 6, the sample placement portion has a flow path through which a fluid passes, and the flow passage is provided around the shaft-like fastening element that fixes the sample placement portion to the gantry. The test thermostat according to any one of claims 1 to 5, wherein:

  In the present invention, since the flow path in the sample placement portion is provided around the shaft-like fastening element, the shaft-like fastening element and the attachment portion of the shaft-like element do not hinder the flow of the fluid (heat medium). Therefore, there is no increase in flow path resistance in the sample placement portion and temperature variation due to fluid (heat medium) stagnation.

  According to a seventh aspect of the present invention, there is provided a semiconductor wafer performance testing apparatus comprising the test thermostat according to any one of the first to sixth aspects.

  According to the test thermostat of the present invention, the sample placement portion during the test is less bent and distorted, and the sample can be placed in a desired test environment.

  The same applies to the test apparatus of the present invention. Since the test thermostatic apparatus is less bent and distorted, it is possible to test electronic components and the like with higher accuracy.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a front view of a test thermostat according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the test thermostat of FIG. FIG. 3 is a cross-sectional view of the test thermostat of FIG. 1 taken along the line AA. 4 is a BB cross-sectional view of the test thermostat of FIG. FIG. 5 is a cross-sectional view taken along the line CC of the test thermostat of FIG. 6 is a DD cross-sectional view of the test thermostat of FIG. 7 is an EE cross-sectional view of the test thermostat of FIG.

The test thermostat 1 shown in the figure is built in a wafer prober and comprises a sample placement unit 2 and a gantry 3.
The sample arrangement part 2 is made of a copper alloy or other metal, and its shape is a two-stage low columnar shape. That is, the sample placement portion 2 is constituted by a large circle portion 5 and a small circle portion 6. The top surface of the sample placement unit 2 constitutes a sample placement surface 7 on which a semiconductor wafer (sample) as a test object is placed.
The back side of the great circle portion 5 of the sample placement portion 2 is a facing surface 9 that faces the sample placement surface 7.

  As shown in FIG. 3, a flow path 8 is formed inside the sample placement portion 2. Two openings 11 and 12 communicating with the flow path 8 are provided on the side surface of the sample placement portion 2. That is, the openings 11 and 12 are for flowing air (heat medium) through the flow path 8 inside the sample arrangement portion, and the opening 11 functions as an inlet and the opening 12 functions as an outlet. A heat medium introducing means (not shown) is connected to the opening 11, and air (heat medium) is sent to the opening 11 by the heat medium introducing means.

The flow path 8 provided inside the sample placement unit 2 communicates with the openings 11 and 12 and is evenly distributed over the entire area of the sample placement unit 2. In this embodiment, an S-shaped curve is repeated, but a spiral flow path may be used.
In the present embodiment, as will be described later, the sample placement portion 2 is fixed to the gantry 3 by screws (axial fastening elements) 20 and 21, but the flow path 8 is a part of the screws (axial fastening elements) 20 and 21. It is provided by detour. That is, the flow path 8 draws a gentle curve around the screw (axial fastening element) and bypasses the site of the screw (axial fastening element).
Therefore, the screws (axial fastening elements) 20 and 21 are not exposed in the flow path, and the screws (axial fastening elements) 20 and 21 do not hinder the flow of air (heat medium).

  An electric heater (not shown) is attached to the small circle portion 6 of the sample placement portion 2. In the test thermostat 1, the temperature of the sample placement surface 7 on the surface of the sample placement portion 2 is adjusted by the heat generated by the electric heater and the cold heat of the air (heat medium) introduced into the flow path 8.

As shown in FIGS. 1 and 2, the gantry 3 includes a connection portion 15, an intermediate portion 16, and a pedestal portion 17.
The connection part 15 is disk shape. The diameter of the connection portion 15 is smaller than the sample placement portion 2 described above, and is less than or equal to one half of the sample placement portion 2. A preferable diameter of the connection portion 15 is about one third of that of the sample placement portion 2.
The material of the connection portion 15 is the same as that of the sample placement portion 2 described above, and the thermal expansion coefficient of the connection portion 15 is the same as that of the sample placement portion 2.

The shape of the intermediate portion 16 is also a disk shape. The diameter of the intermediate portion 16 is smaller than that of the connection portion 15 and is equal to or less than half of the connection portion 15. A preferable diameter of the connection portion 15 is about one third of that of the connection portion 15.
The material of the intermediate portion 16 is different from that of the sample placement portion 2 described above. The property required for the intermediate portion 16 is excellent heat insulation.

  The pedestal 17 is a triangular plate. The performance required for the pedestal portion 17 is rigid, and it is desirable to manufacture it with a metal such as steel. The diameter of the circumscribed circle 26 of the pedestal portion 17 is substantially equal to the sample placement portion 2 described above.

Next, the assembly structure of each member will be described.
The constant temperature test apparatus 1 of the present embodiment is one in which the sample placement unit 2 is attached on the gantry 3, and the gantry 3 is one in which a pedestal part 17, an intermediate part 16, and a connection part 15 are sequentially stacked. It is. The center of the gantry 3 coincides with the center of the sample placement unit 2. That is, the center of the circumscribed circle of the sample placement portion 2, the center of the circumscribed circle of the connecting portion 15, the center of the circumscribed circle of the intermediate portion 16, and the center of the circumscribed circle 26 of the pedestal portion 17 coincide. In the present embodiment, since the sample placement portion 2, the connection portion 15, and the intermediate portion 16 are all circular, the center of the circumscribed circle coincides with the center of the circle.

And each above-mentioned member is couple | bonded by the screw | thread (shaft fastening element). That is, a single screw 20 passes through the center of the pedestal portion 17, the center of the intermediate portion 16, the center of the connection portion 15, and the center of the sample placement portion 2.
In addition, three screws 21 penetrate between the facing surface 9 of the sample placement portion 2 and the connection portion 15. Three screws 22 penetrate between the connecting portion 15 and the intermediate portion 16. Further, three screws 23 penetrate between the intermediate portion 16 and the pedestal portion 17.

A single screw 20 that penetrates all of the pedestal 3 and reaches the sample placement portion 2 passes through the center of the circumscribed circle 26 of the pedestal portion 17, the center of the circumscribed circle of the intermediate portion 16, and the center of the circumscribed circle of the connecting portion 15. The front end is engaged with the center of the circumscribed circle of the sample placement portion 2.
The other screws 21, 22, and 23 are all on a pitch circle centered on the center of each member. Accordingly, the screws 21, 22, and 23 are all concentric, and the center thereof is the screw 20 that passes through the center. All three screws on the pitch circle are provided at equal intervals. That is, the three screws are provided at intervals of 120 degrees.

Looking at the relationship of the pitch circle diameter of each screw, the diameter of the pitch circle A of the screw 21 between the sample placement portion 2 and the connection portion 15 is the diameter of the circumscribed circle of the sample placement portion 2 as shown in FIGS. 1/3 or less.
The diameter of the pitch circle B of the screw 22 between the connecting portion 15 and the intermediate portion 16 is smaller than the diameter of the pitch circle A as shown in FIG.
The diameter of the pitch circle C of the screw 23 between the intermediate portion 16 and the pedestal portion 17 is the same as the diameter of the pitch circle B as shown in FIG.
However, the position of the screw 22 between the connection part 15 and the intermediate part 16 and the position of the screw 23 between the intermediate part 16 and the base part 17 are shifted in the circumferential direction. Specifically, both are shifted by 60 degrees.
Note that the diameter of the pitch circle C and the diameter of the pitch circle B are not necessarily the same.

  The test thermostat 1 of the present embodiment places a sample on the sample placement unit 2 and adjusts the surface temperature of the sample placement unit 2 by an electric heater (not shown) and air (heat medium) flowing through the flow path 8. . Specifically, the surface temperature of the sample placement unit 2 can be set to about 300 degrees Celsius by an electric heater, and the temperature can be lowered to about minus 65 degrees by flowing air (heat medium) through the flow path 8. it can. When the temperature of the sample placement unit 2 is changed in this way, the sample placement unit 2 is thermally expanded or contracted, and each part is displaced.

However, in the test thermostat 1 of this embodiment, although each part is displaced, a change such as warping or distortion does not occur.
That is, in this embodiment, the connection portion 15 is in direct contact with the sample placement portion 2, and the sample placement portion 2 and the connection portion 15 are connected to the center screw 20 and the screw 21 on the surrounding pitch circle A. It is combined with.
Here, in this embodiment, since the sample placement portion 2 and the connection portion 15 are made of the same material, and both are in close contact with each other and the temperature difference between them is small, the displacement at the site of the screw 21 on the pitch circle A is small. Is not much different between the sample placement portion 2 and the connection portion 15. In addition, the sample placement unit 2 and the connection unit 15 have the same amount of expansion and contraction in other parts. Therefore, no stress is applied to the contact surface of the sample placement portion 2 and the connection portion 15 or the screw 21, and the phenomenon that the sample placement portion 2 is warped or dented does not occur.

Moreover, since the size of the connection part 15 is small and the area of the contact surface between the sample placement part 2 and the connection part 15 is small, the amount of heat transferred from the sample placement part 2 to the connection part 15 is small.
Furthermore, since the intermediate part 16 interposed between the connection part 15 and the pedestal part 17 has high heat insulating properties, heat hardly transfers to the pedestal part 17 side. Therefore, there is little thermal deformation of the base part 17 itself.

In the present embodiment, the shape of the pedestal portion 17 is not made circular, but a triangle is adopted.
The reason for this is to minimize the heat radiation received from the back surface (opposite surface) of the sample placement portion 2.
That is, the sample placement unit 2 sets the upper surface of the sample placement surface 7 to a high temperature or a low temperature, but the facing surface 9 facing the sample placement surface also has a considerably high temperature or low temperature. On the other hand, since the pedestal portion 17 faces the facing surface 9 of the sample placement portion 2, it receives thermal radiation from the sample placement portion 2. As a result, there is a concern that the temperature of the pedestal portion 17 changes and is distorted by thermal stress.
Therefore, in the present embodiment, a meat stealing portion is provided in the pedestal portion 17 and the entire shape is formed into a triangle. In the present embodiment, an area overlapping the facing surface 9 is smaller than the facing surface 9 when a projection region formed by projecting the pedestal 17 onto the facing surface of the sample placement unit 2 is assumed.
Therefore, the radiant heat received by the pedestal portion 17 is reduced, and distortion due to thermal stress is reduced. In addition, since wasteful escape of heat is reduced, thermal efficiency is also improved.
In the present embodiment, a triangle is adopted as the shape of the pedestal portion 17, but may be another polygonal shape or a deformed shape such as a star shape as long as the rigidity is satisfied.

  Next, the test apparatus will be described. FIG. 8 is a perspective view of a semiconductor wafer performance test apparatus according to an embodiment of the present invention. As shown in FIG. 8, a semiconductor wafer performance test apparatus (hereinafter simply referred to as a test apparatus) 30 of the present embodiment is largely divided into two apparatuses. That is, the test apparatus 30 is divided into a test section 33 in which the test thermostatic apparatus 1 is built in, and a gas supply apparatus (heat medium introducing means) 25, and between them, a forward side crossover pipe 27 and a return side crossover pipe 28. And are connected by piping. The gas supply device 25 is a device that cools air, and a cooling device is incorporated therein. The test unit 33 belongs to the wafer prober.

  The test thermostat 1 is housed in a housing 32 independent of the gas supply device (heat medium introducing means) 25. There are two pipes in the casing 32 of the test section 33, and the forward side crossover pipe 27 and the opening 11 and the return side crossover pipe 28 and the opening 12 are connected to each other by the pipe. As a result, cooling air is introduced from the gas supply device 25 into the flow path 8 (FIG. 3) via the opening 11. Then, the temperature of the sample placement surface 7 is adjusted by the heat generated by an electric heater (not shown) provided on the bottom surface of the sample placement portion 2 and the cold heat of the cooling air introduced into the flow path 8. Regarding the temperature of the sample mounting surface 7, the temperature and flow rate of the cooling air introduced into the flow path 8 and the output of the electric heater are adjusted so that the temperature can be adjusted to at least minus 65 ° C. to plus 300 ° C. Is done.

  The test thermostat 1 is mounted on an XY table 35 and can be moved to XY by a motor (not shown).

  In this embodiment, the heat medium introduced into the flow path 8 is cooling air, but the heat medium is not particularly limited as long as it is a fluid, and may be a fluid accompanied by either cold or warm heat.

It is a front view of the thermostat for a test concerning an embodiment of the present invention. It is a disassembled perspective view of the thermostat for a test of FIG. It is AA sectional drawing of the thermostat for a test of FIG. It is BB sectional drawing of the thermostat for a test of FIG. It is CC sectional drawing of the thermostat for a test of FIG. It is DD sectional drawing of the thermostat for a test of FIG. It is EE sectional drawing of the thermostat for a test of FIG. 1 is a perspective view of a test apparatus according to an embodiment of the present invention. It is a disassembled perspective view of the conventional thermostat for a test.

DESCRIPTION OF SYMBOLS 1 Test thermostat 2 Sample arrangement | positioning part 3 Base 6 Small circle part 7 Sample mounting surface 8 Flow path 9 Opposing surface 15 Connection part 16 Intermediate | middle part 17 Base part 20, 21, 22, 23 Screw (shaft fastening element)
30 Semiconductor wafer performance test equipment

Claims (7)

A test thermostat having a sample placement portion and a gantry supporting the sample placement portion, and capable of adjusting the temperature of the sample placed in the sample placement portion by adjusting the temperature of the sample placement portion, The sample placement portion has a sample placement surface on which a sample can be placed and a facing surface facing the sample placement surface, and the mount has a connection portion connected to the facing surface. The connecting portion is made of a material having the same coefficient of thermal expansion as that of the sample placement portion, and the connection portion and the sample placement portion are connected via a plurality of shaft-like fastening elements. One is arranged at the center of the circumscribed circle of the sample arrangement portion, and the other plurality of shaft-like fastening elements are on the circumference having a circle that is concentric with the circumscribed circle and smaller than the circumscribed circle as a pitch circle A, axial fastening elements provided on a are arranged at regular intervals, pitch The diameter of A test thermostat, characterized in that less than one third of the diameter of the circumscribed circle of the sample placement part.   The thermostat for testing according to claim 1, wherein a circumscribed circle of the connecting portion of the gantry is smaller than a circumscribed circle of the sample arranging portion.   The gantry has a pedestal part, the pedestal part is opposed to the facing surface of the sample placement part, and the facing is assumed when a projection region formed by projecting the pedestal part on the facing surface of the sample placement part is assumed. The test thermostat according to claim 1 or 2, wherein a region overlapping the surface is smaller than the facing surface.   The gantry includes a connection part, a pedestal part fixed to a predetermined installation surface, and an intermediate part located between the connection part and the pedestal part, and the thermal conductivity of the intermediate part is determined by the connection part. The thermostatic device for testing according to any one of claims 1 to 3, wherein the thermal conductivity is lower than the thermal conductivity.   The connecting portion and the intermediate portion are connected by a shaft-like fastening element arranged on a predetermined pitch circle B, and the intermediate portion and the pedestal portion are connected by a shaft-like fastening element arranged on the pitch circle C, the pitch circle B and the pitch circle C have the same center and diameter, and the axial fastening element that connects the connecting portion and the intermediate portion, and the axial fastening element that connects the intermediate portion and the pedestal portion are at positions separated in the circumferential direction. The test thermostat as claimed in claim 4.   2. The sample placement section has a flow path through which a fluid passes, and the flow path is provided around a shaft-like fastening element that fixes the sample placement section to the gantry. The test thermostat according to any one of 1 to 5.   A semiconductor wafer performance test apparatus comprising the test thermostat according to claim 1.

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