US20120216559A1

US20120216559A1 - Mounting device

Info

Publication number: US20120216559A1
Application number: US13/403,430
Authority: US
Inventors: Hiroshi Yamada
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2011-02-28
Filing date: 2012-02-23
Publication date: 2012-08-30
Also published as: JP2012178527A; TWI518822B; JP5715444B2; KR20120098503A; KR101370235B1; CN102683241A; TW201308465A

Abstract

A mounting device includes a mounting body for mounting thereon a target object to be subjected to a predetermined process; and a cooling mechanism for cooling the target object via the mounting table. The cooling mechanism includes a heat exchanger provided at a bottom surface of the mounting table, and a cooling unit having a heat absorbing unit for absorbing heat from a heat transfer medium of the heat exchanger. Further, the cooling unit is fixed to the heat exchanger through the heat absorbing unit.

Description

FIELD OF THE INVENTION

The present invention relates to a mounting device having a cooling mechanism for cooing a substrate to be processed such as a semiconductor wafer or the like to a predetermined temperature in the case of processing the substrate at a low temperature; and, more particularly, to a mounting device capable of achieving cost reduction by simplifying the cooling mechanism.

BACKGROUND OF THE INVENTION

A conventional mounting device is used for various processing apparatuses in a semiconductor manufacturing field. Here, a mounting device used for an inspection apparatus for inspecting electrical characteristics of a semiconductor wafer will be described as an example.
As shown in FIG. 4, for example, a conventional inspection apparatus E includes a loader chamber L for transferring a semiconductor wafer W, a prober chamber P for inspecting electrical characteristics of the semiconductor wafer W transferred from the loader chamber L, and a control unit (not shown). The inspection apparatus E is configured to transfer the semiconductor wafer W from the loader chamber L to the prober chamber P, and inspect electrical characteristics of the semiconductor wafer W in the prober chamber L, and then return the semiconductor wafer W to the original location, under the control of the control unit.
As shown in FIG. 4, the prober chamber P has a temperature-controllable wafer chuck 1 for mounting thereon a semiconductor wafer W, an XY table 2 for moving the wafer chuck 1 in X and Y directions, a probe card 3 provided above the wafer chuck 1 moved by the XY table 2, and an alignment mechanism 4 for precisely aligning a plurality of probes 3A of the probe card 3 with a plurality of electrode pads of the semiconductor wafer W on the wafer chuck 1.
As shown in FIG. 4, a test head T of a tester is rotatably provided on a head plate 5 of the prober chamber P, and is electrically connected to the probe card 3 through a performance board (not shown). Further, the inspection of the electrical characteristics of the semiconductor wafer W is performed by setting an inspection temperature of the semiconductor wafer W on the wafer chuck 1 at a low temperature range or a high temperature range, for example, and sending signals from the tester to the probes 3A through the test head T.
When the semiconductor wafer W is subjected to low-temperature inspection, a coolant is cooled by a cooling unit 6 connected to the wafer chuck 1 and the semiconductor wafer W is cooled to a low temperature range of, e.g., about several tens of minus degrees, by circulating the cooled coolant through a coolant path in the wafer chuck 1, as can be seen from FIG. 5. In Japanese Patent Application Publication No. 2007-240035, the present inventors have suggested a cooling/heating unit as the cooling unit 6. As shown in FIG. 5, this cooling/heating unit 6 includes: a coolant tank 61 for storing a coolant; a first coolant circulation path 62 for circulating the cooing liquid between the wafer chuck 1 and the coolant tank 61 through a first pump 62A; a second coolant circulation path 63 for circulating the coolant in the coolant tank 61 through a second pump 63A; a temperature sensor 61A for detecting a temperature of the coolant; a temperature controller 64 operating based on the detection value of the temperature sensor 61A; a heat engine driving inverter (hereinafter, simply referred to as an “inverter”) 65 operating based on the signal from the temperature controller 64; and a Stirling engine 66 (see FIG. 2) operating based on the signal from the inverter 65. The coolant circulating in the second coolant circulation path 63 is heated or cooled by the Stirling engine 66.
When the coolant is cooled by the cooling/heating unit 6, the coolant in the coolant tank 61 circulates between the first coolant circulation path 62 and the wafer chuck 1 by the operation of the first pump 62A, thereby cooling the wafer chuck 1. The temperature of the coolant returned to the coolant tank 61 is increased. The temperature of the coolant in the coolant tank 61 is detected by the temperature sensor 61A, and the detection signal is sent to the temperature controller 64. The temperature controller compares a preset temperature with the detection temperature and drives the inverter 65 based on the temperature difference therebetween. The inverter 65 drives the Stirling engine 66 at a predetermined frequency based on the instruction signal from the temperature controller 64. In the Stirling engine 66, the coolant circulating in the second coolant circulation path 63 by the second pump 63A is cooled by a heat exchanger 67. The cooling/heating unit 6 shown in FIG. 5 has a simple line structure without using valves, so that machine breakdown and power consumption can be reduced.
However, the mounting device using the cooling/heating unit 6 shown in FIG. 5 requires the installation space for the coolant tank 61, the first and the second coolant circulation paths 62 and 63, the first and the second pump 62A and 63A, the Stirling engine 66 and the like. Accordingly, the cooling unit used in the mounting device cannot achieve space saving.

SUMMARY OF THE INVENTION

In view of the above, the present invention provides a mounting device capable of achieving cost reduction and space saving of a cooling mechanism for cooling a target object, e.g., a semiconductor wafer or the like, mounted on a mounting body.
In accordance with one aspect of the present invention, there is provided a mounting device including: a mounting body for mounting thereon a target object to be subjected to a predetermined process; and a cooling mechanism for cooling the target object via the mounting table, wherein the cooling mechanism includes a heat exchanger provided at a bottom surface of the mounting table, and a cooling unit having a heat absorbing unit for absorbing heat from a heat transfer medium of the heat exchanger, and wherein the cooling unit is fixed to the heat exchanger through the heat absorbing unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention will become apparent from the following description of embodiments, given in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross sectional view showing an embodiment of a mounting device of the present invention;

FIG. 2 schematically shows a cooling unit applied to the mounting device shown in FIG. 1;

FIG. 3 is a cross sectional view showing another embodiment of the mounting device of the present invention.

FIG. 4 shows an internal structure of an inspection apparatus having a conventional mounting device; and

FIG. 5 is a diagram showing an example of a mounting device used in the inspection apparatus shown in FIG. 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the present invention will be described based on embodiments shown in FIGS. 1 to 3.
As shown in FIG. 1, a mounting device 10 of the present embodiment includes a mounting body (wafer chuck) 11 for mounting thereon a semiconductor wafer W, a cooling mechanism 12 for cooling the semiconductor wafer W, a support body 13 for supporting the wafer chuck 11 at an outer periphery thereof, and an elevation mechanism 15 for supporting and vertically moving the support body 13 on a base 14 at a plurality of locations. The elevation mechanism 15 may be configured as, e.g., a cylinder mechanism, but not limited thereto. The mounting device 10 can be applied to an inspection apparatus for inspecting electrical characteristics of the semiconductor wafer W, for example.
A probe card 20 is provided above the wafer chuck 11. The probe card 20 is installed at a head plate 30 forming a top surface of the prober chamber of the inspection apparatus via a card holder 20A. An alignment mechanism (not shown) is provided in the prober chamber to perform alignment between the semiconductor wafer W on the wafer chuck 1 and the probes 21 of the probe card 20.
When the semiconductor wafer W is subjected to low-temperature inspection, the semiconductor wafer W on the wafer chuck 11 is cooled to a predetermined temperature in a low-temperature range, e.g., several tens of minus degrees, by the cooling mechanism 12. While the semiconductor wafer W is being cooled, the alignment between the electrode pads of the semiconductor wafer W on the wafer chuck 11 and the probes 21 of the probe card 20 is performed by the alignment mechanism. Next, the wafer chuck 11 is raised by the elevation mechanism 15, and the electrode pads of the semiconductor wafer W are brought into electrical contact with the probes 21 of the probe card 20. In that state, the electrical characteristics of the devices formed on the semiconductor wafer W are inspected at a predetermined low temperature.
As shown in FIG. 1, the cooling mechanism 12 includes a heat exchanger 121 provided at a central portion of a bottom surface of the wafer chuck 11, a cooling unit 122 having a heat absorbing unit 122A inserted into the heat exchanger 121 at the side surface of thereof. The cooling unit 122 is horizontally fixed to the side surface of the heat exchanger 121 through the heat absorbing unit 122A. The heat exchanger 121 has a heat transfer medium 121A, and a housing body 121B accommodating therein the heat transfer medium 121A. The heat transfer medium 121A is made of metal having high thermal conductivity, and the housing body 121B is made of a heat insulating material. As shown in FIG. 1, the cooling unit 122 has the heat absorbing unit 122A, and a driving unit 122B extending in a horizontal direction of the heat absorbing unit 122A. The heat absorbing unit 122A and the driving unit 122B are formed as one unit in a housing.
The cooling unit 122 will be described with reference to FIG. 2. As shown in FIG. 2, the heat absorbing unit 122A includes a first cylinder 122C, a displacer 122D capable of reciprocally moving within the first cylinder 122C, a regenerator 122E provided at an outer peripheral surface of the first cylinder 122C, and a first housing member 122F accommodating therein the above components. An operation gas is filled in the first housing member 122F. As shown in FIG. 2, the driving unit 122B has a second cylinder 122G disposed directly below the first cylinder 122C, a piston 122H configured to be reciprocally moved within the second cylinder 122G, a driving mechanism 122I for reciprocally moving the piston 122H, and a second housing member 122J for accommodating the above components. In the second housing member 122J, the piston 122H reciprocally moves within the second cylinder 122G by the driving mechanism 122I. The first housing member 122F and the second housing member 122J are formed as a single housing. Further, the first housing member 122F and the second housing member 122J are partitioned outside the second cylinder 122G. In this cooling unit 122, the first cylinder 122C and the second cylinder 122G have the same outer diameter and the same inner diameter. Moreover, the first cylinder 122C and the second cylinder 122G may be formed as one unit, and a through hole may be formed at the lower end of the heat absorbing unit 122A.
As shown in FIG. 2, in the housing, when the driving mechanism 122I is driven, the piston 122H reciprocally moves along the second cylinder 122G, and the displacer 122D provided thereabove reciprocally moves within the first cylinder 122C while maintaining a specific phase difference with respect to the piston 122H. At this time, the operation gas reciprocally moves through the regenerator 122E in directions indicated by arrows. As a consequence, an expanded space and a compressed space are formed at an upper and a lower side of the displacer 122D, respectively. In the expanded space, the temperature of the operation gas is decreased, so that heat is absorbed from the outside. In the compressed space, the temperature of the operation gas is increased, so that heat is radiated to the outside. In the expanded space, heat is absorbed through a heat absorbing fin. In the compressed space, heat is radiated through a heat radiation fin.
Therefore, while the displacer and the piston are reciprocally moving within the first and the second cylinder while maintaining the specific phase difference therebetween, the stirling cycle in which the operation gas is repeatedly compressed and expanded is performed. Heat is absorbed at the leading end portion of the heat absorbing unit 122A and is radiated from a place between the displacer 122D and the piston 122H. Since the heat absorbing unit 122A is inserted into the heat exchanger 121 as shown in FIG. 1, the heat absorbing unit 122A absorbs heat from the heat transfer medium 121A. The wafer chuck 11 is cooled through the heat transfer medium 121A, so that the semiconductor wafer W on the wafer chuck 11 can be cooled.
The cooling mechanism 12 used in the present embodiment is directly attached to the bottom surface of the wafer chuck 11. Hence, unlike the conventional case in which the wafer chuck is cooled by using a coolant, it is possible to omit the coolant tank, the coolant circulation line, the circulation pump and the like. Since the installation space of such components becomes unnecessary, the structure of the cooling mechanism 12 can be largely simplified, and considerable cost reduction can be achieved.
In FIG. 1, the example in which the cooling unit 122 is horizontally attached to the side surface of the heat exchanger 121 is illustrated. However, the cooling unit 122 may be vertically attached on the bottom surface of the heat exchanger 121, as shown in FIG. 3. In that case, a central axis of the cooling unit 122 coincides with that of the wafer chuck 11, so that the mounting device 10 can be moved horizontally while maintaining balance. Further, in the cooling unit 122, the driving unit 122B is supported so as to be vertically movable by an elevation mechanism 16.
Hereinafter, the operation will be explained. First, in order to inspect electrical characteristics of the semiconductor wafer W, the wafer chuck 11 of the mounting device 10 is previously cooled by the cooling mechanism 12. At this time, in the cooling mechanism 12, the driving mechanism 122I of the driving unit 122B of the cooling unit 122 is driven to reciprocally move the piston 122H along the second cylinder 122G, as shown in FIG. 2. When the piston 122H reciprocally moves, the displacer 122D in the heat absorbing unit 122A reciprocally moves along the first cylinder 122C while maintaining the specific phase difference with respect to the piston 122H. At this time, the operation gas is expanded at the upper side of the displacer 122D, and heat is absorbed from the heat transfer medium 121A of the heat exchanger 121 via the heat absorption fin. Meanwhile, the operation gas is compressed at a space between the displacer 122D and the piston 122H and has an increased temperature, so that heat is radiated outside the housing through the heat radiation fin. By repeating this stirling cycle at regular intervals, the heat absorbing unit 122A gradually absorbs heat from the heat transfer medium 122A of the heat exchanger 121, and the wafer chuck 11 is cooled. The heat absorbed by the heat absorbing unit 122A is radiated outside the housing from the space between the displacer 122D and the piston 122H via the heat radiation fin.
While the wafer chuck 11 is being cooled by the cooling mechanism 12, the pre-aligned semiconductor wafer W is mounted on the wafer chuck 11. The semiconductor wafer W is aligned with respect to the probe card 20 by the alignment mechanism. Then, the elevation mechanism 15 is driven to raise the wafer chuck 11 cooled to a predetermined temperature (e.g., about −50° C.), and the electrode pads of the semiconductor wafer W and the probes 21 of the probe card 20 electrically contact with each other. In that state, the inspection is performed at a predetermined low temperature. Upon completion of the low-temperature inspection of the semiconductor wafer W, the semiconductor wafer W is returned from the wafer chuck 11 to the original location, and a next semiconductor wafer W is subjected to a low-temperature inspection.
As described above, in accordance with the present embodiment, the cooling mechanism 12 installed at the mounting device 10 includes: the heat exchanger 121 provided at the bottom surface of the wafer chuck 11; and the cooling unit 122 having the heat absorbing unit 122A for absorbing heat from the heat transfer medium 121A of the heat exchanger 121. Since the cooling unit 122 is fixed to the heat exchanger 121 through the heat absorbing unit 122A, the conventionally required components such as the coolant for cooling the wafer chuck 11, the coolant tank, the coolant circulation line and the like become unnecessary. Therefore, the structure of the cooling mechanism 12 is very simplified, and the space saving of the cooling mechanism 12 is achieved. Furthermore, the cost reduction can be achieved.
The present invention may be properly modified, if necessary, without being limited to the above-described embodiments. In the above-described embodiments, a mounting device used in an inspection apparatus has been described. However, the present invention can be widely applied to a mounting device having a function of cooling a target object. Besides, the heat transfer medium 121A of the heat exchanger 121 may be made of a material other than metal. Further, a Stirling cooler used as the cooling unit 122 is not limited to one described in the above-described embodiments. If necessary, the components thereof may be properly modified.
While the invention has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

Claims

1. A mounting device comprising:

a mounting body for mounting thereon a target object to be subjected to a predetermined process; and

a cooling mechanism for cooling the target object via the mounting table,

wherein the cooling mechanism includes a heat exchanger provided at a bottom surface of the mounting table, and a cooling unit having a heat absorbing unit for absorbing heat from a heat transfer medium of the heat exchanger, and

wherein the cooling unit is fixed to the heat exchanger through the heat absorbing unit.

2. The mounting device of claim 1, wherein the cooing unit is configured as a Stirling cooler.

3. The mounting device of claim 1, wherein the heat transfer medium is made of metal.

4. The mounting device of claim 1, further comprising a support body for supporting the mounting body at an outer periphery thereof and an elevation mechanism for vertically moving the support body.

5. The mounting device of claim 4, wherein the elevation mechanism is configured as a cylinder mechanism.

6. The mounting device of claim 1, wherein the substrate to be processed is subjected to an electrical characteristic inspection.