KR101500050B1 - Method and apparatus for cooling subject to be processed, and computer-readable storage medium - Google Patents

Abstract

A method of cooling an object to be processed capable of suppressing the generation of scratches on the back surface of the object is disclosed. In this cooling method, the heated workpiece W is loaded on the workpiece support pin 50 supporting the workpiece W under the pressure of the vacuum process, and the workpiece W is separated from the cooling member, A step of supplying a cooling gas for cooling the object to be processed at a first flow rate to raise the pressure around the object to a first pressure higher than the vacuum processing pressure to cool the object for a first time, A cooling gas is supplied at a second flow rate greater than the first flow rate while the object to be processed is placed on or close to the cooling member so that the pressure around the object to be processed is raised to a second pressure higher than the first pressure, For a second period of time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for cooling an object to be processed, a cooling apparatus, and a computer readable storage medium.

The present invention relates to a method of cooling an object to be processed, a cooling device, and a computer-readable storage medium.

In a manufacturing process of a semiconductor device, processes such as a film forming process and an etching process are performed under a vacuum pressure on a semiconductor wafer (hereinafter simply referred to as a wafer) to be processed. In the film forming apparatus or the etching apparatus for performing such vacuum processing, pressure conversion must be performed between the atmospheric pressure and the vacuum processing pressure in order to transfer the wafer from the wafer cassette placed in the air to the vacuum. In the present development, this pressure conversion is performed by providing a load lock chamber between the wafer cassette and the film forming apparatus or the etching apparatus, and performing pressure conversion in the load lock chamber.

Incidentally, the film forming process, the etching process, and the like are processes accompanied by a pressure of a vacuum process and a high temperature. The wafer taken out from the film forming apparatus or the etching apparatus is at a high temperature of, for example, about 500 캜. When the wafer in a high temperature state is exposed to the atmosphere, the wafer is oxidized, and when the wafer in a high temperature state is returned to the wafer cassette, problems such as melting of the wafer cassette as a resin occur.

To avoid this problem, wait for the wafer to cool down to a temperature at which no problem occurs. However, if the temperature of the wafer is waiting to be lowered, the throughput is lowered. As a result, as disclosed in Japanese Patent Application Laid-Open No. 2009-182235, a cooling plate having a cooling mechanism for cooling the wafer is provided in the load lock chamber, and while the wafer is returned from the vacuum processing pressure to the atmospheric pressure, Is performed.

However, when the wafer is suddenly cooled, the wafer is warped due to the difference in thermal expansion of the front and back surfaces of the wafer, and the center portion or the edge portion of the wafer is separated from the cooling plate. As a result, the cooling efficiency is lowered and consequently the cooling time becomes longer, or the wafer is exposed to the atmosphere while leaving the high temperature portion.

In order to prevent such wafers from being warped, the rising speed of the pressure when returning the load lock chamber to atmospheric pressure and the distance between the wafer and the cooling plate, i.e., the height position of the wafer are managed. The prescribed fuzzy recipes are prepared for each temperature of the wafer. However, the degree of deformation of the wafer also varies depending on the kind of film formed on the wafer. In addition, the number of film types is enormous for each user, and it is extremely difficult to prepare an optimal fuzzy recipe for each film type.

In order to solve such a difficulty, Japanese Patent Laid-Open Publication No. 2009-182235 proposes a displacement sensor for detecting the deformation of the wafer during cooling, adjusts the pressure and height position of the wafer while monitoring the bending state of the wafer during cooling .

At present, the cooling technique has progressed so far as to suppress the warping of the wafer during cooling as described in Japanese Patent Application Laid-Open No. 2009-182235. However, even if the warpage of the wafer during cooling can be suppressed, the wafer under cooling shrinks. As a result, when the wafer is retracted, the back surface of the wafer is rubbed against the cooling plate or the wafer support pin, and micro scratches such as micro-scratches are generated on the back surface of the wafer.

Until today, the minute scratches on the backside of the wafer have not been a problem. However, it has been found that defects caused by minute scratches on the back surface of the wafer occur in the exposure process due to miniaturization of the semiconductor device, and the yield is lowered. The minute scratches generated on the back surface of the wafer cause micro irregularities on the back surface of the wafer. Repeatedly performing the film forming process on the wafer, the film forming gas is introduced into the back surface of the wafer, so that the thin film gradually accumulates on the convex portion, and the convex portion becomes large. The enlarged convex portion deteriorates the flatness of the surface of the wafer placed on the exposure stage.

The minute scratches generated on the back surface can be removed by polishing the back surface of the wafer. Growing of the convex portion can be suppressed by backside cleaning of the wafer. However, in the case where the backside polishing or the backside cleaning is not performed, or the backside polishing or the backside cleaning can not be carried out in the process, the wafer is subjected to a film forming process Or the exposure process.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a cooling method, a cooling apparatus, and a computer readable storage medium that can suppress the occurrence of scratches on the back surface of an object to be processed.

A method for cooling an object to be processed according to a first aspect of the present invention is a method for cooling an object to be processed in which a heated object is cooled by using a cooling member having a cooling mechanism, the method comprising: (1) A cooling gas for cooling the object to be processed is supplied at a first flow rate in a state in which the object to be processed is placed on the object supporting pin supporting the object under the pressure of the vacuum process and the object to be processed is separated from the cooling member, A step of raising the pressure of the periphery of the object to a first pressure higher than the pressure of the vacuum processing to cool the object for a first time; and (2) lowering the object to be processed, The cooling gas is supplied at a second flow rate greater than the first flow rate so that the pressure around the subject is lower than the first pressure And a step of raising the pressure to a second high pressure to further cool the object to be processed for a second time.

A cooling device according to a second aspect of the present invention is a cooling device according to the second aspect of the present invention that includes a container configured to be capable of fluctuating an internal pressure between a vacuum processing pressure and an atmospheric pressure, a cooling gas supply mechanism for supplying a cooling gas into the container, A cooling member provided in the container and having a cooling mechanism that cools the object to be processed by placing or closing the object to be processed; and a cooling member provided so as to protrude and retreat from the cooling member, A workpiece support pin for receiving the workpiece in a protruding state from the cooling member and lowering the workpiece in a state of receiving the workpiece to load or bring the workpiece to be loaded or brought into proximity to the cooling member; Wherein the cooling gas supply mechanism, the cooling mechanism, and the object supporting member are provided so as to be cooled according to a cooling method of the object to be processed And a control unit for controlling the control unit.

A computer readable storage medium according to a third aspect of the present invention is a computer readable storage medium storing a control program for controlling a cooling apparatus, the computer program being operable on a computer, To control the cooling device so as to perform the cooling method of the object to be processed in accordance with the control signal.

1 is a plan view schematically showing an example of a semiconductor manufacturing system to which a method of cooling an object to be processed according to an embodiment of the present invention can be applied.
2 is a sectional view showing an example of a load lock unit;
FIG. 3A is a sectional view showing an example of a method of cooling an object to be processed according to an embodiment; FIG.
3B is a cross-sectional view showing an example of a method of cooling an object to be processed according to an embodiment.
3C is a cross-sectional view showing an example of a method of cooling an object to be processed according to an embodiment;
4 is a time chart according to an example of a method of cooling an object to be processed according to an embodiment;
5A is a cross-sectional view showing a state in which a semiconductor wafer is brought close to a mounting surface of a cooling plate.
5B is a cross-sectional view showing a state in which the semiconductor wafer is brought close to the mounting surface of the cooling plate.
6 is an enlarged cross-sectional view showing a distal end portion of the contact portion;
7 is a view showing the state of a back surface of a silicon wafer cooled according to a method of cooling an object to be processed according to an embodiment after completion of cooling.
8 is a time chart according to a cooling method according to a comparative example.
9 is a view showing the state of a back surface of a silicon wafer cooled according to a cooling method according to a comparative example after completion of cooling.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, common reference numerals are assigned to common parts throughout the drawings.

1 is a plan view schematically showing an example of a semiconductor manufacturing system to which a method of cooling an object to be processed according to an embodiment of the present invention can be applied. 1 shows a multi-chamber type semiconductor manufacturing system including a load lock unit having a load lock chamber.

1, the semiconductor manufacturing system includes four vacuum processing units 1, 2, 3 and 4 for performing high temperature processing such as film forming processing, and each of these vacuum processing units 1 4 are provided corresponding to the four sides of the hexagonal transport chamber 5, respectively. Load lock units 6 and 7 are provided on the other two sides of the transport chamber 5, respectively. A loading / unloading chamber 8 is provided on the side opposite to the transfer chamber 5 of these load lock units 6 and 7 and a semiconductor wafer 1 as an object to be processed is provided on the side opposite to the load lock units 6 and 7 of the loading / Ports 9, 10, and 11 for installing three FOUPs (Front Opening Unified Pods) capable of accommodating W are provided. The vacuum processing units 1, 2, 3 and 4 are subjected to a predetermined vacuum process, for example, a film forming process or an etching process, with the object to be processed placed on the process plate.

The vacuum processing units 1 to 4 are connected to the respective sides of the transfer chamber 5 via gate valves G and communicate with the transfer chamber 5 by opening corresponding gate valves G, G is closed so as to be disconnected from the transport chamber 5. The load lock units 6 and 7 are connected to the remaining sides of the transfer chamber 5 via the first gate valve G1 and the second gate valve G2 is connected to the load / . The load lock chambers 6 and 7 communicate with the transfer chamber 5 by opening the first gate valve G1 and shut off from the transfer chamber by closing the first gate valve G1. Further, the second gate valve G2 is opened to communicate with the loading / unloading chamber 8, and the second gate valve G2 is closed to shut off the loading / unloading chamber 8.

In the transfer chamber 5, a transfer device 12 for transferring the semiconductor wafers W into and from the vacuum processing units 1 to 4 and the load lock units 6 and 7 is provided. The transfer device 12 includes two support arms 14a and 14b which are disposed substantially at the center of the transfer chamber 5 and which support the semiconductor wafer W at the tip of the rotation and expansion and contraction portion 13, And these two support arms 14a and 14b are provided on the rotation / extension portion 13 so as to face opposite directions. The inside of the transport chamber 5 is maintained at a predetermined degree of vacuum.

A shutter (not shown) is provided in each of the three ports 9, 10 and 11 for installing the FOUP F, which is a wafer storage container of the loading / unloading chamber 8, and the wafers W are accommodated in these ports 9, 10 and 11 , Or the empty hoop F is directly installed, and when installed, the shutter is separated so as to communicate with the loading / unloading chamber 8 while preventing intrusion of outside air. Further, an alignment chamber 15 is provided on the side surface of the carry-in / out chamber 8, and alignment of the semiconductor wafer W is performed there.

A transfer device 16 is provided in the loading / unloading chamber 8 for loading / unloading the semiconductor wafers W to / from the FOUP F and loading / unloading the semiconductor wafers W to / from the load lock units 6 and 7. The transfer device 16 has a multi-jointed arm structure and is capable of traveling on the rail 18 along the arrangement direction of the FOUP F, and the semiconductor wafer W is mounted on the hand 17 at the tip end thereof And the transfer is performed.

This vacuum processing system has a process controller 20 composed of a microprocessor (computer) for controlling each component, and each component is connected to the process controller 20 and controlled. The process controller 20 is also provided with a user interface 21 composed of a keyboard for the operator to input a command or the like for managing the vacuum processing system or a display for visualizing and displaying the operating status of the plasma processing apparatus, .

The process controller 20 is also provided with a control program for realizing various processes to be executed in the vacuum processing system under the control of the process controller 20 and a control program for executing various processes in the respective components of the vacuum processing system A storage section 22 storing a program, for example, a film-forming recipe relating to a film-forming process, a transport recipe relating to transfer of wafers, a purge recipe concerning pressure adjustment inside the load lock chamber, and the like are connected. These various recipes are stored in the storage medium in the storage unit 22. [ The storage medium may be a fixed one such as a hard disk, or a portable one such as a CD-ROM, a DVD, and a flash memory. Further, the recipe may be appropriately transmitted from another apparatus, for example, through a dedicated line.

If necessary, an arbitrary recipe is called from the storage unit 22 by the instruction from the user interface 21 to be executed by the process controller 20, so that under the control of the process controller 20, Is performed. The process controller 20 controls the pressure and the height of the wafer W so as to control the deformation of the wafer in the process of performing the processing based on the standard fuzzy recipe in the load lock units 6 and 7 .

Fig. 2 is a sectional view showing an example of the load lock units 6 and 7. Fig.

As shown in Fig. 2, the load lock units 6 and 7 have a container 31 configured to be able to fluctuate the internal pressure between a vacuum processing pressure and an atmospheric pressure, There is provided a cooling member having a cooling mechanism for cooling the semiconductor wafer W by loading or bringing the wafer W close thereto. In this embodiment, the cooling member is a cooling plate 32, and the cooling plate 32 is installed in the container 31 while being supported by the leg portion 33.

One side wall of the container 31 is provided with an opening 34 communicable with the conveying chamber 5 held in vacuum and an opening 35 communicating with the carry- Is formed. The opening 34 can be opened and closed by the first gate valve G1, and the opening 35 can be opened and closed by the second gate valve G2.

An exhaust port 36 for evacuating the inside of the container 31 and a cooling gas inlet port 37 for introducing the cooling gas into the container 31 are provided at the bottom of the container 31. An exhaust pipe 41 is connected to the exhaust port 36 and the exhaust pipe 41 is provided with an on-off valve 42, an exhaust speed control valve 43 and a vacuum pump 44. A cooling gas introduction pipe 45 for introducing a cooling gas into the container 31 is connected to the cooling gas introduction port 37. The cooling gas introduction pipe 45 extends from the cooling gas source 48 And an on-off valve 46 and a flow rate control valve 47 are provided in the middle of the operation.

Closing valve 46 is closed and the open / close valve 42 is opened when carrying the wafer W to / from the transfer chamber 5 on the vacuum side. In this state, the exhaust speed control valve 43 is adjusted to exhaust the inside of the container 31 through the exhaust pipe 36 by the vacuum pump 44 at a predetermined speed, 5). When the pressure in the container 31 becomes a pressure corresponding to the pressure in the transport chamber 5, the first gate valve G1 is opened to communicate between the container 31 and the transport chamber 5. [ When carrying the wafer W to / from the atmosphere-side carry-in / out chamber 8, the open / close valve 42 is closed and the open / close valve 46 is opened. In this state, the flow control valve 47 is adjusted to introduce the cooling gas from the cooling gas source 48 into the vessel 31 through the cooling gas introduction pipe 45. An example of a method of introducing the cooling gas will be described later. The second gate valve G2 is opened to communicate between the container 31 and the loading / unloading chamber 8 when the pressure in the container 31 becomes the atmospheric pressure or the pressure corresponding to the vicinity of the atmospheric pressure.

The opening / closing valve 42, the exhaust speed adjusting valve 43, the flow regulating valve 47 and the opening / closing valve 46 are controlled by a valve control mechanism 49. By controlling these valves, the inside of the container 31 is changed between the atmospheric pressure and the vacuum. Further, the valve control mechanism 49 is controlled based on an instruction from the process controller 20. [

A plurality of, for example, nine (only two shown) wafer support pins 50 for transferring the wafer are provided on the cooling plate 32 so as to protrude and retract from the surface of the cooling plate 32, The pin (50) is fixed to the support plate (51). The wafer support pin 50 is lifted and lowered through the support plate 51 by lifting the rod 52 by a drive mechanism 53 such as a motor capable of adjusting the raised position. In addition, reference numeral 54 denotes bellows.

A cooling medium flow path 55 is formed as a cooling mechanism in the cooling plate 32. A cooling medium introduction piping 56 and a cooling medium discharge piping 57 are connected to the cooling medium flow path 55, A cooling medium such as cooling water flows from a cooling medium supply unit which is not provided, so that the loaded wafer W can be cooled.

The process controller 20 also controls the load lock units 6 and 7 and controls the valve control mechanism 49 and the drive mechanism 53 in accordance with the process recipe to control the pressure in the vessel 31 and the pressure in the wafer W As shown in FIG.

Next, a method of cooling an object to be processed according to an embodiment of the present invention will be described.

FIG. 3 is a cross-sectional view showing an example of a method of cooling an object to be processed according to an embodiment of the present invention, and FIG. 4 is a time chart according to an example of a method of cooling an object according to an embodiment of the present invention . 3A to 3C, the container 31, the gate valves G1, G2, and the like are not shown.

First, as shown in Figs. 3A and 4, the pressure in the container 31 is set to a pressure corresponding to the pressure in the transport chamber 5. Fig. In this example, although the pressure used when processing in the vacuum processing units 1 to 4 is different depending on the process, the pressure in the transport chamber 5 is almost constant, for example, several Torr, . Further, the wafer support pins 50 are raised so as to protrude from the mounting surface 32a of the cooling plate 32.

Subsequently, as shown in Figs. 3B and 4, the gate valve G1 is opened to be processed in any one of the vacuum processing units 1 to 4 from the transfer chamber 5, for example, at a temperature of 300 ° C to 500 ° C Of the semiconductor wafer W is carried into the container 31, and is loaded on the wafer support pin 50. Subsequently, the gate valve G1 is closed and the cooling gas is slowly supplied to the container 31 at a flow rate of, for example, 3000 sccm for about 5 seconds while the semiconductor wafer W is separated from the mounting surface 32a of the cooling plate 32 So that the pressure in the container 31, that is, the pressure around the semiconductor wafer W, is slightly raised to a pressure of 50 Torr (6650 Pa) or more, exceeding the vacuum processing pressure (slow purge 1 in FIG. In this example, the state in which the semiconductor wafer W is spaced apart from the mounting surface 32a and the wafer support pins 50 are not lowered is referred to as a state in which the wafer support pins 50 receive the semiconductor wafer W. The distance L1 between the semiconductor wafer W and the mounting surface 32a in this state is, for example, about 20 mm in this example.

In this example, the supply of the cooling gas is stopped (the valve 46 in Fig. 4 is closed) while the wafer support pin 50 receives the semiconductor wafer W. In this state, it is held for about 5 seconds. The waiting process for holding the wafer for about 5 seconds can be omitted depending on, for example, the size of the semiconductor wafer W and the temperature at which the semiconductor wafer W is heated.

In the step shown in Fig. 3B, a small amount of cooling gas is slowly supplied while the semiconductor wafer W is separated from the mounting surface 32a. This causes slow heat exchange between the semiconductor wafer W and the cooling gas for several seconds after the start of cooling. By the slow heat exchange, the heated semiconductor wafer W is slowly cooled.

The semiconductor wafer W is contracted by the start of cooling. In this example, a small amount of cooling gas is slowly supplied at the start of cooling (time T1 in FIG. 4). As a result, the shrinkage start speed of the semiconductor wafer W at the start of cooling can be made as close to zero as possible. The "friction" between the back surface of the semiconductor wafer W and the contact portion 50a of the wafer support pin 50 when the semiconductor wafer W starts to shrink can be relieved.

Further, the semiconductor wafer W is not moved without lowering the wafer support pins 50 for several seconds after the start of cooling. The temperature of the semiconductor wafer W is still high for several seconds from the start of cooling. It is considered that the high temperature semiconductor wafer W tends to be scratched more than the low temperature semiconductor wafer W. [ Therefore, mechanical vibration is not applied to the semiconductor wafer W without lowering the wafer support pins 50 for several seconds after the start of cooling. Further, if the pressure rising speed in the vessel 31 is too high, there is a possibility that the semiconductor wafer W held on the wafer support pin 50 may be displaced. Therefore, the pressure rising speed may be set to a pressure (for example, several Torr) The same degree is preferable, for example, 2 to 9 Torr / sec, and more preferably 3 to 5 Torr / sec. Thus, unnecessary " friction " of the back surface of the semiconductor wafer W and the contact portion 50a can be suppressed within several seconds from the start of cooling.

Next, as shown in FIG. 3C and FIG. 4, when the temperature of the semiconductor wafer W is lowered to some extent, the wafer support pins 50 are lowered to move the semiconductor wafer W to the mounting surface 32a of the cooling plate 32, Or placed on the floor.

The state in which the semiconductor wafer W is brought into close proximity is a state in which the semiconductor wafer W protrudes from the mounting surface 32a in a state (see Fig. 5A) closer to the mounting surface 32a than the state shown in Fig. 3B or on the mounting surface 32a , And a state in which the fixed support pin 32b is provided to slightly lift the semiconductor wafer W from the mounting surface 32a (refer to FIG. 5B). The distance L2 between the semiconductor wafer W and the mounting surface 32a when the semiconductor wafer W is slightly raised by using the support pin 32b is, for example, about 0.5 mm. The cooling gas is supplied into the container 31 at a flow rate equal to that of the slow purge 1 and at a flow rate of 3000 sccm, for example, in a state where the semiconductor wafer W is loaded or placed on the mounting surface 32a of the cooling plate 32. [ And the pressure in the container 31 is raised to a pressure of 100 Torr (13330 Pa) or less (slow purge (2) in FIG. 4). Subsequently, the flow rate of the cooling gas is raised at a flow rate of, for example, 30000 sccm and supplied for about 20 seconds (main purge in Fig. 4). Thereby, the pressure in the container 31, that is, the pressure around the semiconductor wafer W, is raised to the atmospheric pressure or the pressure near the atmospheric pressure. The pressure in the vicinity of the atmospheric pressure is, for example, a pressure in the range of ± 5% with respect to the atmospheric pressure. Thus, the semiconductor wafer W can be held at a temperature at which no oxidation is generated in the semiconductor wafer W by the cooling plate 32 and the cooling gas, or at a temperature at which the semiconductor wafer does not melt the wafer cassette made of resin, And cooled.

Further, in an example of the cooling method of the object according to the embodiment, the wafer support pin 50 is also devised. As described with reference to Fig. 3B, when the cooling of the semiconductor wafer W is started, the semiconductor wafer W is contracted. By the contraction, the back surface of the semiconductor wafer W rubs against the contact portion 50a of the wafer support pin 50.

Thus, in this example, the Vickers hardness of the contact portion 50a of the wafer support pin 50 which is in contact with at least the workpiece, in this example, the semiconductor wafer W is made to be not more than the Vickers hardness of the back surface of the semiconductor wafer W. Specifically, when the object to be processed is a silicon wafer and the back surface is silicon, at least the contact portion 50a of the wafer support pin 50 is made of quartz.

In this way, by making the material of the contact portion 50a at least quartz, the Vickers hardness of the contact portion 50a can be made equal to or less than the Vickers hardness of the back surface of the silicon wafer. This makes it possible to further suppress occurrence of scratches due to friction between the back surface of the silicon wafer and the contact portion 50a.

In this example, the shape of the tip of the contact portion 50a is also designed. Fig. 6 is an enlarged cross-sectional view showing the distal end portion of the contact portion 50a.

As shown in Fig. 6, in this example, the shape of the tip of the contact portion 50a is a spherical surface. By making the tip of the contact portion 50a have a spherical shape, scratches on the back surface of the semiconductor wafer W can be made less likely to occur as compared with the case where the tip portion of the contact portion 50a is flat.

In addition, if the spherical surface is severely curved, the front end of the contact portion 50a becomes acute, and the back surface of the semiconductor wafer W is easily scratched. Thus, in this example, the radius of curvature of the spherical surface is set to 5 mm. This makes it possible to further suppress the occurrence of scratches on the back surface of the semiconductor wafer W, as compared with the case where the radius of curvature of the spherical surface is, for example, 2 mm.

In addition, if the spherical bending state is gentle, the front end of the contact portion 50a becomes close to the plane, so that the back surface of the semiconductor wafer W is liable to be scratched. From this point of view, the upper limit of the radius of curvature of the spherical surface is preferably about 10 mm.

In short, the radius of curvature of the spherical surface of the distal end portion of the contact portion 50a is preferably 5 mm or more and 10 mm or less.

Fig. 7 shows the state of the back surface of the silicon wafer cooled according to the cooling method of the object according to the above-described embodiment after completion of cooling.

As shown in Fig. 7, the state of the back surface of the silicon wafer is such that a contact mark is visible, and a minute scratch such as a micro-scratch is not seen.

As a comparative example, the contact portion of the wafer support pin was cooled according to the time chart shown in Fig. 8, and the material of the contact portion of the wafer support pin was alumina (harder than the Vickers hardness of the back surface of the silicon wafer) Fig. 9 shows the state of the back surface after cooling is completed.

As shown in Fig. 9, the state of the back surface of the silicon wafer as the comparative example shows a minute scratch like a micro scratch.

As described above, according to the method of cooling an object to be processed according to the above embodiment, the heated semiconductor wafer W is loaded on the wafer support pin 50 under a vacuum processing pressure, and the semiconductor wafer W is separated from the cooling plate 32 The semiconductor wafer W is slowly cooled for several seconds from the start of cooling. Thereby, abrupt contraction of the semiconductor wafer W at the start of cooling of the semiconductor wafer W can be suppressed, and occurrence of scratches on the back surface of the semiconductor wafer W can be suppressed.

Further, during the process for several seconds from the start of cooling, the wafer support pins 50 are not moved. By further including this configuration, it is possible to prevent the semiconductor wafer W from applying mechanical vibration to the semiconductor wafer W for several seconds after the start of cooling, which is still high temperature. This makes it possible to suppress the generation of scratches on the back surface of the semiconductor wafer W in a period in which the semiconductor wafer W likely to be scratched is at a high temperature.

It is also assumed that the material of the contact portion 50a of the wafer support pin 50 is equal to or less than the Vickers hardness of the back surface of the semiconductor wafer W. [ By further having this configuration, occurrence of scratches on the back surface of the semiconductor wafer W can be further suppressed.

The shape of the tip of the contact portion 50a is a spherical surface. By further having this configuration, occurrence of scratches on the back surface of the semiconductor wafer W can be more restrained.

As described above, according to one embodiment of the present invention, there can be provided a cooling method of an object to be processed which can suppress the generation of scratches on the back surface of the object to be processed, a cooling device capable of implementing the cooling method, It is possible to provide a computer-readable storage medium capable of performing the above-described operations.

The present invention is not limited to the above embodiment, and various modifications are possible. In addition, the embodiment of the present invention is not the only one of the above embodiments.

For example, in the above-described embodiment, a multi-chamber type vacuum processing system in which four vacuum processing units and two load lock units are provided has been described as an example. However, the number is not limited to this number, And the load lock unit may be provided in the vacuum processing unit.

In the above embodiment, the processing time is specified as shown in Fig. 4. The processing time is not limited to the time shown in Fig. If the following steps (1) and (2) are provided, the treatment time can be appropriately changed and set according to the size of the object to be treated and the heating temperature.

(1) The heated object to be processed is placed on a workpiece support pin supporting the workpiece under a vacuum processing pressure, and a cooling gas for cooling the workpiece in a state where the workpiece is separated from the cooling member A step of cooling the object to be processed for a first time by raising the pressure around the object to be processed to a first pressure higher than the vacuum processing pressure

(2) The workpiece support pin is lowered to supply the cooling gas at a second flow rate larger than the first flow rate while the workpiece is being mounted on or close to the cooling member, so that the pressure around the workpiece is reduced to the first pressure A second step of cooling the object to be processed for a second time,

In addition, the present invention can be suitably modified within the scope not deviating from the spirit of the present invention.

Claims (12)

A method for cooling an object to be processed in which a heated object is cooled by using a cooling member having a cooling mechanism,
(1) cooling the object to be processed by cooling the object to be processed in a state where the heated object is loaded on the object supporting pin supporting the object to be processed under a vacuum processing pressure and the object to be processed is separated from the cooling member A step of supplying the gas at a first flow rate to raise the pressure around the subject to a first pressure higher than the pressure of the vacuum treatment to cool the subject for a first time;
(2) a step of stopping the supply of the cooling gas while waiting for the object to be processed to be placed on the object supporting member and spaced from the cooling member,
(3) the processing-object supporting pin is lowered to supply the cooling gas at a second flow rate that is larger than the first flow rate, while the object to be processed is placed on or close to the cooling member, And further cooling the object to be processed for a second time by raising the pressure of the object to a second pressure higher than the first pressure,
The method of cooling an object to be treated, wherein the object supporting pin is not moved during the steps (1) and (2). delete The method according to claim 1, wherein the first pressure is set to a pressure of not more than 50 Torr exceeding the pressure of the vacuum processing, and the second pressure is set to a pressure near atmospheric pressure or atmospheric pressure. The method according to claim 1, wherein in the step (1), the object to be processed is separated from the cooling member, and the object supporting pin receives the object to be processed. The method according to claim 1, wherein the Vickers hardness of the contact portion of the object supporting member with at least the object to be processed is made to be Vickers hardness of the back surface of the object. The method according to claim 5, wherein, when the object to be processed is a silicon wafer, quartz is used as a material of at least a portion of the object supporting pin that contacts the object to be processed. The method according to claim 1, wherein the shape of the distal end portion of the contact portion of the object supporting member with the object to be treated is a spherical surface, and the radius of curvature of the spherical surface is 5 mm or more and 10 mm or less. A vessel in which the pressure inside the vessel is configured to be variable between the pressure of the vacuum processing and the atmospheric pressure,
A cooling gas supply mechanism for supplying a cooling gas into the vessel,
An exhaust mechanism for exhausting the inside of the container,
A cooling member provided in the container and having a cooling mechanism for cooling the object to be processed by placing or closing the object to be processed,
And a cooling member which is provided so as to protrude and retract with respect to the cooling member, receives the object to be processed in a state protruding from the cooling member, and lowering the object in a state of receiving the object to be processed, A workpiece support pin,
And a control device for controlling the cooling gas supply mechanism, the cooling mechanism, and the object supporting member so as to cool the object to be processed according to the cooling method of the object to be processed set forth in claim 1. 9. The cooling device according to claim 8, wherein a Vickers hardness of at least a contact portion of the object supporting member with the object to be processed is not higher than Vickers hardness of the object to be processed. 10. The cooling device according to claim 9, wherein when the object to be processed is a silicon wafer, the material of the contact portion of the object supporting member with at least the object to be processed is quartz. 9. The cooling device according to claim 8, wherein the shape of the contact portion of the object supporting member with the object to be processed is a spherical surface. A computer-readable storage medium storing a control program that operates on a computer and controls a cooling apparatus,
The control program controls the cooling device such that the cooling method of the object according to claim 1 is performed at the time of execution.

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