Inspection system

An inspection system, for inspecting an inspection target on a stage in a low temperature environment, includes a system main body including an inspection apparatus having inspection chambers each accommodating an inspection unit for performing electrical inspection of an inspection target on a stage and having inspection spaces arranged in multiple stages vertically, the plurality of inspection chambers being arranged horizontally, and a loader unit for transferring the inspection target with respect to the stage of the inspection unit; and a coolant supply unit configured to supply a coolant to the stage. The system main body further includes coolant line arrangement spaces, in which coolant lines extending from the coolant supply unit are arranged, provided above or below the respective inspection spaces to correspond to the respective inspection spaces, and the coolant lines are directed toward the corresponding inspection spaces in each of the coolant line arrangement spaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2017-151113 filed on Aug. 3, 2017, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to an inspection system for inspecting a substrate in a low temperature region.

BACKGROUND OF THE INVENTION

In a semiconductor device manufacturing process, a plurality of semiconductor elements (devices) formed on a semiconductor wafer (hereinafter, simply referred to as “wafer”) as a substrate is electrically inspected upon completion of all processes in the wafer. Generally, an inspection apparatus for performing electrical inspection includes a loader unit for transferring a wafer and a prober unit for performing electrical inspection of the wafer transferred from the loader unit. The prober unit includes a wafer stage (chuck top) for holding a wafer, a probe card having probes to be in contact with a plurality of devices formed on the wafer, and an aligner for performing position alignment of the wafer and the probe card. Various electrical characteristics of the device are inspected by applying an electrical signal to the devices formed on the wafer from a tester through the probe card.

A semiconductor device may operate under a low temperature environment of, e.g., −30° C. In order to ensure the operation of the semiconductor device under such an environment, it is required, to perform electrical inspection of the device by controlling a temperature of the wafer to such a low temperature region.

As for an inspection apparatus for performing inspection in a low temperature region, there is suggested an apparatus for cooling a wafer stage provided in a housing to a predetermined low temperature region by supplying a coolant to the wafer stage and preventing condensation on the wafer stage by supplying air of a low dew point into the housing (e.g., Japanese Patent Application Publication No. H9-298225).

Recently, in order to efficiently perform the electrical inspection on a plurality of wafers, there is used an inspection apparatus (inspection system) in which a plurality of inspection units, each including a wafer stage, a probe card, and a tester, is horizontally arranged in each of multiple stages arranged in a height direction (e.g., Japanese Patent Application Publication No. 2013-254812).

If the electrical inspection can be performed in a low temperature region by the inspection system having a plurality of inspection units, the electrical inspection in the low temperature region can be efficiently performed.

In the inspection apparatus having a single prober unit as disclosed in Japanese Patent Application Publication No. H9-298225, it is possible to cool the wafer stage simply by connecting a line for supplying and discharging the coolant from an external chiller unit to the wafer stage. However, in the inspection system in which the inspection units are arranged vertically and horizontally as disclosed in Japanese Patent Application Publication No. 2013-254812, the wafer stage is provided in each of the inspection units and, thus, a plurality of coolant lines is required. If the coolant line is directly connected to the wafer stage from the outside, it is difficult to perform maintenance.

In the inspection system in which the inspection units are arranged vertically and horizontally, it is difficult to set the entire system to a low dew point environment and also difficult to deal with condensation. In addition, since the inspection unit has a complicated inner structure, it is required to extend the coolant line connected to the wafer stage and a large space may be required to ensure the space for the coolant line.

SUMMARY OF THE INVENTION

In view of the above, the present disclosure provides a technique capable of easily performing maintenance, preventing condensation, and performing low temperature inspection while saving a space in an inspection system having a configuration in which a plurality of inspection units is arranged vertically and horizontally.

In accordance with an aspect, there is provided an inspection system for inspecting an inspection target on a stage in a low temperature environment. The inspection system includes: a system main body including an inspection apparatus having a plurality of inspection chambers each accommodating an inspection unit for performing electrical inspection of an inspection target on a stage and having a plurality of inspection spaces arranged in multiple stages in a vertical direction, the plurality of inspection chambers being arranged in a horizontal direction, and a loader unit configured to transfer the inspection target with respect to the stage of the inspection unit of the inspection apparatus; and a coolant supply unit configured to supply a coolant to the stage. The system main body further includes a plurality of coolant line arrangement spaces, in which a plurality of coolant lines extending from the coolant supply unit are arranged, provided above or below the respective inspection spaces to correspond to the respective inspection spaces, and the coolant lines are directed toward the corresponding inspection spaces in each of the coolant line arrangement spaces.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. is a perspective view showing an external appearance of an inspection system according to an embodiment.FIG. 2is a top view showing the external appearance of the inspection system according to the embodiment.FIG. 3is a horizontal cross sectional view showing a system main body of the inspection system according to the embodiment.FIG. 4is a cross sectional view of the system main body shown inFIG. 3which is taken along a line IV-IV′.FIG. 5is a cross sectional view of the system main body shown inFIG. 3which is taken along the Y direction.

An inspection system100of the present embodiment configured to inspect electrical characteristics of a plurality of devices formed on a wafer as a target object in a low temperature environment of, e.g., −30° C. The inspection system100includes a system main body200for performing actual inspection, and a coolant supply unit300for supplying a coolant to the system main body200.

As shown inFIGS. 1 and 2, the system main body200includes an inspection apparatus12having a plurality of inspection units for performing electrical inspection on a wafer (devices formed on the wafer), and a loader unit13for transferring a wafer to the inspection apparatus12.

The coolant supply unit300has three chiller units120for supplying a coolant to the system main body200. A coolant line group60including a plurality of coolant lines for supplying a coolant from the chiller units120or returning a coolant to the chiller units120extends into the system main body200. A reference numeral130denotes a heat exchanger.

As shown inFIGS. 3 to 5, the system main body200is formed by connecting the inspection apparatus12and the loader unit13.

In the inspection apparatus12, four inspection chambers (cells)24are arranged along the X direction and the array of the four inspection chambers is arranged in three stages along the Z direction (vertical direction). The inspection chambers in each stage communicate with each other to form a single inspection space that is substantially sealed. Thus, an upper inspection space12a, an intermediate inspection space12b, and a lower inspection space12care formed. A coolant line arrangement space27where the coolant line group60extends from the coolant supply unit300is provided between the upper inspection space12aand the intermediate inspection space12b, between the intermediate inspection space12band the lower inspection space12c, and below the lower inspection space12c. As will be described later, four coolant supply lines61and four coolant return lines62are provided as the coolant line group60in each coolant line arrangement space27to correspond to the four inspection units30directly above the corresponding coolant line arrangement space27. A rear side of the inspection apparatus12which is opposite to a side facing the loader unit13is set to a maintenance side.

The inspection unit (prober)30including a tester31for wafer inspection, a probe card32, and a chuck top (wafer stage)36for holding the wafer W is provided in each of the inspection chambers24. In each of the upper inspection space12a, the intermediate inspection space12b, and the lower inspection space12c, a single aligner (stage)28capable of moving in the X direction and configured to align the wafer W and attach/detach the wafer W to/from the four inspection units30arranged in the X direction is provided below the inspection unit30. Further, in each of the upper inspection space12a, the intermediate inspection space12b, and the lower inspection space12c, a single alignment camera29capable of moving in the X direction is provided closer to the loader unit13than the inspection unit30. The inspection unit30will be described in detail later.

A cell control unit25that is a control device of each of the inspection units30is provided at a rear side of each of the inspection chambers24. The cell control unit25includes a solenoid, a vacuum sensor, an electro-pneumatic regulator, an E-IOM substrate, a temperature controller and the like. The E-IOM substrate that is an electric device, the solenoid that is an air/vacuum device, the vacuum sensor, and the electro pneumatic regulator are separated from each other. A transfer port24ais provided at a front side of each of the inspection chambers24. The transfer port24acan be opened and closed by a shutter26. The inspection chamber24and the cell control unit25communicate with each other.

The loader unit13includes: a loading/unloading unit14, in which mounting tables19for mounting thereon FOUPs18as containers accommodating a plurality of wafers W, a probe card loader20and a position alignment unit21are arranged in the X direction, disposed to face the inspection apparatus12; and a transfer chamber23, provided between the loading/unloading unit14and the inspection apparatus12, where a transfer mechanism22for transferring the wafer W moves. A control unit90is provided inside the loading/unloading unit14.

As shown inFIG. 5, the transfer mechanism22includes: a transfer arm51for supporting the wafer W; a rotation driving unit52for supporting and rotating the transfer arm; a base portion53for supporting the rotation driving unit52; a cylindrical cover member54that is a container which is supported by the rotation driving unit52and encompasses the transfer arm51; a frame-shaped member55fixed to a side of the base portion53facing the inspection apparatus12and having a transfer port55afor the wafer W; and a shielding wall (not shown) formed as one unit with the frame-shaped member55to cover a part of an outer periphery of the cover member54. The cover member54is configured to rotate with the transfer arm51by the rotation driving unit52. Further, the cover member54has a transfer port54afor the wafer W. Dry air of a low dew point can be supplied into the cover member54. By supplying dry air of a low dew point into the cover member54in a state where the transfer port54ais blocked by the shielding wall by rotating the cover member54, it is possible to create a low dew point environment and deal with condensation. The transfer mechanism22is movable in the Z direction and the X direction.

The transfer mechanism22receives uninspected wafers W from the FOUP18by the back-and-forth movement and the rotation in the θ direction of the transfer arm51and transfers the wafers W to the inspection chambers24in each stage. Further, the transfer mechanism22receives inspected wafers K and returns the wafers W to the FOUP18. When the wafers W are transferred with respect to the inspection chamber24, a low dew point environment is created inside the cover member54by dry air, and the wafers W are transferred by aligning the transfer ports54a,55aand24ain a state where the frame-shaped member55is brought into close contact with a peripheral portion of the transfer port24aof the inspection chamber24.

Further, the transfer mechanism22transfers probe cards requiring maintenance from the inspection units30to the probe card loader20and also transfers a new probe card or a probe card that has been subjected to maintenance to the inspection units30.

FIG. 6shows a schematic configuration of the inspection unit30. The inspection unit30includes: a tester31for sending an inspection signal to devices formed on the wafer W; a probe card32having a plurality of probes32ato be in contact with electrodes of the devices formed on the wafer W; a supporting plate33, provided below the tester31, for supporting the probe card32; a contact block34for connecting the tester31and the probe card32; a bellows35suspended from the supporting plate33and surrounding the probe card32; and a chuck top (wafer stage)36for attracting and holding the wafer W by vacuum suction and controlling a temperature of the wafer W. A plurality of pogo pins34afor electrically connecting the probe card32and the tester31is provided on an upper and a lower surface of the contact block34. The bellows35is used for forming a sealed space encompassing the probe card32and the wafer W in a state where the wafer W on the chuck top36is brought into contact with the plurality of probes32aof the probe card32. By evacuating the sealed space through a vacuum line, the chuck top36is attracted to the supporting plate33. The probe card32is also attracted to the supporting plate33by evacuation.

The aligner23includes: an X block42movable in the X direction on a guide rail41provided on a base plate in a corresponding stage; a Y block42movable in the Y direction on a guide rail43provided on the X block42; and a Z block45movable in the Z direction with respect to the Y block44. The chuck top36is engaged on the Z block45in a state where predetermined positional relation is maintained. A lower camera46for imaging a lower surface of the probe card32is provided on a peripheral wall of the Y block44.

The aligner28can access the inspection units30by moving the X block42in the X direction. The chuck top36for mounting thereon a wafer is moved in the X direction, the Y direction and the Z direction by moving the X block42, the Y block44and the Z block45by a moving unit (not shown) so that the position alignment of the wafer W as an inspection target with respect to each inspection unit30, mounting of the wafer W on the chuck top36to the probe card32, separation of the wafer W on the chuck top36from the probe card32, transfer of the wafer K with respect to the transfer mechanism22, or the like can be performed.

When transferring the wafer W to the chuck top36and attach the wafer W to the probe card32, the wafer is transferred from the transfer mechanism22onto the chuck top36on the aligner28; the wafer W is aligned with the probe card32; the chuck top36is then raised by the aligner28. Accordingly, the wafer W is brought into contact with the probes32aof the probe card32. Thereafter, the chuck top36is raised further to press the wafer N against the probes32a. In this state, the chuck top36is attracted to the supporting plate33by evacuating the space surrounded by the bellows35, and the state in which the wafer is pressed against the probes32ais maintained. In this state, electrical inspection using the tester31is started. At this time, the Z block45of the aligner22is retreated downward, and the aligner22is moved to another inspection unit30where the inspection has been completed.3yperforming the above-described operations in a reverse order, the chuck top36after the inspection is lowered and the inspected wafer W on the chuck top36is returned to the FOUP18by the transfer mechanism22.

The three chiller units120of the coolant supply unit300correspond to the inspection unit30of the upper inspection space12a, the inspection unit30of the intermediate inspection space12b, and the inspection unit30of the lower inspection space12c, respectively. Four coolant supply lines61and four coolant return lines62extend from the coolant line group60connected to each chiller unit120.

The four coolant supply lines61and the four coolant return lines62connected to each chiller unit120extend to the coolant line arrangement space21in the system main body200. The coolant supply lines61and the coolant return lines62are flexible lines (hoses). The coolant supply lines61and the coolant return lines62extend toward the maintenance side (rear side) at positions corresponding to the inspection units30directly above them and are bent upward toward the cell control unit25. Then, the coolant supply lines61and the coolant return lines62are connected, via the cell control unit25, to the chuck top36in the corresponding inspection chamber24(seeFIG. 5). A low-temperature coolant is supplied from each chiller unit120to the chuck, tops36of the inspection units30in the corresponding stage through the coolant supply lines61and returned to each chiller unit120through the coolant return lines62. In the case of performing low temperature inspection at, e.g., −30° C., a coolant of −35° C. is used.

The following configuration is provided to prevent condensation from occurring at any position of the system in the case of supplying a low-temperature coolant.

An atmospheric atmosphere of a room temperature is maintained in a space between the chiller unit120and the system main body200. Therefore, if the surface temperatures of the coolant supply lines61and the coolant return lines62are low, condensation occurs on the surfaces of the coolant supply lines61and the coolant return lines62. Accordingly, a thick heat insulating material such as foamed urethane or the like covers the coolant supply lines61and the coolant return lines62to make the surface temperatures of the coolant supply lines61and the coolant return lines62higher than a dew point.

When the heat insulating material is deformed by the contact between the lines, the heat insulating effect deteriorates. Therefore, as shown inFIG. 7, the contact between the four coolant supply lines61and the four coolant return lines62from each chiller unit120is prevented by using a frame64for guiding the lines and a line arrangement member65for fixing the coolant supply lines61and the coolant return lines62which are covered with the heat insulating material with a gap interposed therebetween. Specifically, the four coolant supply lines61and the four coolant return lines62from each chiller unit120are grouped and suspended downward from each chiller unit120. The contact between the suspended four coolant supply lines61and the suspended four coolant return lines62is prevented by the line arrangement member65. Then, the lines are guided horizontally by the frame64and allowed to enter the coolant line arrangement space27. At this time, in order to prevent the deformation of the heating insulating material due to the contact between the four coolant supply lines61and the four coolant return lines62, a line arrangement member66having a two-stage structure is provided at a horizontal portion of the four coolant supply lines61and a horizontal portion of the four coolant return lines62to divide the four coolant supply lines61and the four coolant return lines62into an upper part and a lower part. If necessary, the line arrangement member65may be provided in the horizontal portion.

As shown inFIG. 6, the line arrangement member65has two plates67, each having four protrusions67aprojecting outward in a triangular shape corresponding to the respective lines61(62), and the lines61(62) are disposed between the two plates67with heat insulating materials68interposed therebetween. The line arrangement member66has a configuration in which the line arrangement: members65are connected in two stages.

The four coolant supply lines61and the four coolant return lines62extending from each chiller unit120are inserted into each coolant line arrangement space27of the system main body200.

The system main body200including twelve inspection units30and the transfer system has a complicated structure Therefore, it is difficult to set all the regions in the system main body200to a low dew point environment. In the present embodiment, various ways to prevent condensation are examined.

In the coolant line arrangement space27, it is difficult to thickly cover the lines with the heat insulating material in view of space saving. Therefore, the thickness of the heat insulating material is set to, e.g., about 6 mm, and the coolant supply lines61and the coolant return lines62are covered with a resin cover70as can be seen fromFIG. 9. A low dew point environment is created by supplying dry air having a dew point temperature lower than a temperature of the coolant, preferably dry air having a dew point temperature of −45° C. or less, e.g., −70° C., at an appropriate flow rate into the cover70. Dry air supplied from a dry air supply unit (not shown) is from the coolant supply unit300side through the lines.

The cover70includes a main cover71provided along a longitudinal direction (X direction) of the coolant line arrangement space27, and individual covers72extending from the main cover71toward the maintenance side (rear side) at positions corresponding to the four inspection units30. As shown inFIG. 10, the four coolant supply lines61and the four coolant return lines62, which are alternately arranged, reach the main cover71at the entrance side of the coolant line arrangement space27and are sequentially distributed from the main cover71to the four individual covers72.

Dry air is supplied to create a low dew point environment and prevent condensation. However, if the cover70is sealed, dry air stays in the cover70and the surface temperatures of the coolant supply lines61and the coolant return lines62are lowered, which results in condensation. Therefore, a plurality of slits73is formed in the cover70, and dry air is discharged through the slits73. Accordingly, the flow of dry air in the cover70is improved and condensation is prevented. The slits73are formed on the surfaces of the main cover71and the individual covers72of the cover70. The flow of the dry air is controlled by increasing the number of slits73at a downstream side of the flow of dry air.

When the coolant supply lines61and the coolant return lines62are densely arranged, the convection of dry air between the lines becomes poor and condensation occurs. Accordingly, as shown inFIG. 10, the lines are distributed into groups directed toward the respective inspection units30to avoid dense arrangement. If the lines are brought into contact with each other at a portion where the lines are disposed in parallel, the convection of dry air becomes poor at that portion and condensation occurs. Therefore, in the individual covers72, as shown inFIG. 11A, a spacer heat insulating material75having recesses corresponding to the lines is provided below the coolant supply line61and the coolant return line62, and a space of, e.g., about 10 mm, is provided between the coolant supply line61and the coolant return line62. In the main cover71, as shown inFIG. 11B, a spacer heat insulating material77having spacers between these lines is provided below the coolant supply line61and the coolant return line62, and a gap of, e.g., 2.5 mm, is provided between the coolant supply line61and the coolant return line62in order to improve the convection of dry air between the lines and ensure the convection between the lines. The individual covers72and the main cover71are made of resin, and insulating materials76and78are provided therein. Accordingly, condensation on the surface of the cover70can be prevented. Further, the convection of dry air in the individual covers72and the main cover71is ensured by setting a distance between the coolant supply line61and the coolant return line62and the heat insulating materials76and78to 5 mm or more.

As described above, the coolant supply line61and the coolant return line62which have reached the maintenance side of the coolant line arrangement space27are bent upward and reach the cell control unit25. As shown inFIG. 12, the bent portion is covered with a resin cover60having an inner surface covered with a heat insulating material81, thereby preventing condensation.

The upper inspection space12a, the intermediate inspection space12b, and the lower inspection space12care independent spaces separated from each other. Dry air having a dew point temperature lower than the temperature of the coolant is supplied into these spaces. Accordingly, a low dew point environment is created in the inspection chamber24and the cell control unit25. Dry air is purged at a predetermined flow rate from the cell control unit25to the resin cover80through a dry air tube (not shown) and then discharged to the outside.

In order to guide the coolant supply line61and the coolant return line62from the coolant line arrangement space27to the chuck top36, the coolant supply line61and the coolant return line62are connected to a metal joint32(only one is shown) fixed in the middle thereof. The metal joint82is provided in the cell control unit25in a low dew point environment. Therefore, it is possible to suppress condensation on the metal joint82. However, the metal joint82is resin-fixed, and condensation may occur at components (cover, screws or the like) near the low-temperature metal joint82through the resin. Accordingly, the metal joint82including a fixing part is covered with a heat insulating material cover83. A reference numeral84denotes a spacer.

The coolant supply line61and the coolant return line62from the metal joint82reach the inspection chamber24from the cell control unit25and are connected to the chuck top36of the inspection unit30. At this time, condensation does not occur at the chuck top36and other members due to a low dew point environment created in the inspection chamber24and the cell control unit25and convection of dry air.

The control unit90is basically a computer and includes a main controller having a CPU, an input device (keyboard, mouse or the like), an output device (printer or the like), a display device (display or the like), and a storage device (storage medium). The main controller controls the respective components of the inspection system100, e.g., the testers31of the inspection units30, the vacuum suction mechanism, the aligner28, the transfer mechanism22, the chiller unit120and the like, and also controls the supply of dry air. The main controller of the control unit90controls the inspection system100to perform a predetermined operation based on, e.g., a processing recipe stored in a storage medium built in the storage device or a storage medium set in the storage device.

In the inspection system100configured as described above, the surface temperature of the chuck top36is set to, e.g., −30° C., by supplying a coolant from the chiller unit120of the coolant supply unit300to the chuck top36of each inspection unit30of the system main body200, and the electrical inspection of the wafer K is performed in a low temperature environment.

In the system main body200, the operations of transferring the wafer W from the FOUP18mounted on the mounting table19of the loader unit13to each inspection unit30by the transfer mechanism22, performing the electrical inspection on the wafer W, and returning the wafer W after the inspection to the FOUP18by the transfer mechanism22are performed concurrently and consecutively.

The supply of the coolant to the chuck tops36of the plurality of inspection units30through the coolant lines is not considered, and it is considered to directly connect the coolant lines to the chuck tops36from the outside in view of a single inspection unit. However, if the coolant lines are directly connected to the chuck tops36from the outside, it is difficult to perform maintenance. In addition, since the inspection system having a plurality of inspection units has a complicated structure, it is difficult to deal with condensation, and a space for extending the coolant lines is required, which makes it difficult to save space.

On the other hand, in the present embodiment, the coolant supply line63and the coolant return line62as coolant lines introduced from the chiller unit120of the coolant supply unit300into the system main body200are extended to the dedicated coolant line arrangement space27provided below the inspection chambers24in each stage and are connected to the chuck top36of the inspection unit30in each inspection chamber24. Therefore, the coolant can be supplied to the chuck top36without hindering the maintenance. Further, since the coolant supply line61and the coolant return line62are provided in the dedicated coolant line arrangement space27, there are no other components and it is easy to deal with condensation. In addition, there is no need to extend the coolant line to a portion where various devices are provided. The coolant line arrangement space21may be small as long as the coolant lines can be disposed, which makes it possible to save the space.

In the coolant line arrangement space27, the coolant supply line61and the coolant return line62are covered with a heat insulating material having a thickness enough to realize space saving and then covered with the cover70including the main cover71and the individual covers72. The coolant supply line61and the coolant return line62are guided to a position corresponding to each inspection chamber24on the maintenance side while creating a low dew point environment by supplying dry air having a dew point temperature lower than the temperature of the coolant and causing convection of the dry air. Therefore, in the coolant line arrangement space27, the surface temperatures of the coolant supply line61and the coolant return line62can become higher than the dew point temperature and it is possible to prevent condensation on the surfaces of the lines.

At this time, due to a small inner space of the cover, the flow of dry air may become poor and condensation may occur due to the low surface temperatures of the coolant supply line61and the coolant return line62. On the other hand, the flow of dry air is improved by discharging dry air through the slits73formed in the cover70to the outside. Therefore, condensation on the surfaces of the lines can be more effectively prevented.

Among the plurality of coolant supply lines61and the plurality of coolant return lines62in the main cover71, the lines are distributed in groups directed to the respective inspection units30to avoid dense arrangement. Further, the coolant supply line61and the coolant return line62are provided on the spacer heat insulating materials75and77. Accordingly, a space is generated between the lines, and it is possible to prevent condensation from occurring due to dry air staying between the lines. In addition, the cover70is made of resin and a heat insulating material is provided therein, which makes it possible to suppress a decrease in the surface temperature of the cover70and prevent condensation on the surface of the cover70.

The cell control unit25having therein electric devices and air/vacuum devices for performing various control of the inspection unit30is provided at the maintenance side (rear side) of each inspection chamber24. Further, the inspection chamber24and the cell control unit25are made to communicate with each other, and a low dew point environment is created therein by supplying dry air having a dew point temperature lower than the temperature of the coolant. Therefore, condensation on the devices in the cell control unit25is prevented. Even if air enters during the transfer of the wafer W on the chuck top36, the condensation on the devices can be prevented. The metal joint82of the coolant supply line63and the coolant return line62is provided in the cell control unit25under the low dew point environment, and the metal joint82including the fixing part is covered with the heat insulating cover83. Accordingly, it is possible to prevent condensation on the metal joint82and its surrounding components (cover, screws or the like).

The transfer mechanism22transfers the wafer W with respect to the chuck top36of the inspection unit in a state where the frame-shaped member55is brought into close contact with a peripheral portion of the transfer port24aof the inspection chamber24by opening the shutter26after a low dew point environment is created by supplying dry air having a low dew point into the cover member54in a state where the transfer arm51is surrounded by the cover member54and the transfer port54aof the cover member54is shielded by a shielding wall (not shown). Accordingly, condensation on the chuck top can be prevented even during the transfer of the wafer W. Even if air enters the inspection chamber24and the cell control unit25during the transfer of the wafer W, the low dew point environment therein is hardly affected.

The coolant supply line61and the coolant return line62between the coolant supply unit300and the system main body200are covered with a thick heat insulating material having high insulating property such as foamed urethane or the like. Therefore, the surface temperature of the coolant supply line61and the coolant return line62becomes higher than the dew point. Further, due to the presence of the frame64for guiding the lines, the line arrangement member65for fixing the lines with a gap interposed therebetween, and the line arrangement member66for fixing the lines in a two stage structure, the deformation of the heat insulating material by the contact between the lines can be prevented and, further, the decrease in the heat insulating effect can be prevented. Accordingly, it is possible to prevent condensation on the coolant supply line61and the coolant return line62between the coolant supply unit300and the system main body200.

The present disclosure is not limited to the above embodiment, and various modifications can be made within the scope of the idea of the present disclosure.

For example, in the above-described embodiment, the coolant line arrangement space of the system main body is disposed below each stage in which the inspection chambers are arranged. However, the present disclosure is not limited thereto, and the coolant line arrangement space may be provided above each stage.

In the above-described embodiment, four inspection chambers are arranged in one stage and three stages are provided in a height direction. However, the present disclosure is not limited thereto, and the number of stages may vary depending on the arrangement space of the inspection system.

In the above-described embodiment, the transfer mechanism has a configuration in which the cover member for encompassing the transfer arm is provided, and the inner space of the cover member can be set to a low dew point environment by suppling dry air thereinto during the transfer of the wafer with respect to the chuck top in the inspection chamber. However, the wafer may be transferred in an atmospheric atmosphere without providing the cover member. In that case as well, it is possible to efficiently prevent condensation without being greatly affected by the low dew point environment of the inspection chamber or the like.

While the present disclosure has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present disclosure as defined in the following claims.