JP2011091373A - Cooling method, cooling device, and computer-readable storage medium of workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling method of a workpiece capable of suppressing microscratches on the back of the workpiece. <P>SOLUTION: The cooling method of the workpiece W comprises a step for cooling the workpiece W for a first time by mounting the heated workpiece W on a workpiece supporting pin 50 to support the workpiece W under the pressure of vacuum treatment, supplying a cooling gas to cool the workpiece W at a first flow volume in a state that the workpiece W is separated from a cooling member, and raising its ambient pressure to a first level higher than that of the vacuum treatment, and a step for further cooling the workpiece W for a second time by lowering the workpiece supporting pin, supplying the cooling gas at a second flow volume larger than that of the first flow volume in a state that the workpiece is put on the cooling member or brought close to the member, and raising its ambient pressure to a second level higher than the first level. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  In the manufacturing process of a semiconductor device, a process such as a film forming process or an etching process is performed on a semiconductor wafer (hereinafter simply referred to as a wafer) as an object to be processed under a vacuum pressure. In a film forming apparatus or an etching apparatus that performs such vacuum processing, in order to transport the wafer from the wafer cassette placed in the atmosphere into the vacuum, pressure conversion is performed between the atmospheric pressure and the vacuum processing pressure. There must be. At present, 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 the pressure conversion in the load lock chamber.

  By the way, a film forming process, an etching process, and the like are processes involving a pressure of vacuum processing and a high temperature. The wafer carried out from the film forming apparatus or the etching apparatus is in a high temperature state of about 500 ° C., for example. When the high temperature wafer is exposed to the atmosphere, the wafer is oxidized, and when the high temperature wafer is returned to the wafer cassette, the resin wafer cassette is melted.

  In order to avoid such an inconvenience, it is sufficient to wait until the wafer is lowered to a temperature at which no inconvenience occurs. However, when waiting for the wafer temperature to drop, throughput decreases. For this reason, as described in Patent Document 1, a cooling plate having a cooling mechanism for cooling the wafer is provided in the load lock chamber, and the wafer is cooled while returning from the vacuum processing pressure to the atmospheric pressure. (Patent Document 1).

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

  In order to prevent such warpage of the wafer, the rising speed of the pressure when returning the load lock chamber to the atmospheric pressure and the distance between the wafer and the cooling plate, that is, the height position of the wafer are managed. A purge recipe that defines an appropriate combination of these is created for each wafer temperature. However, the degree of deformation of the wafer varies depending on the type of film formed on the wafer. Moreover, there are an enormous number of film types for each user, and it is extremely difficult to create an optimal purge recipe for each film type.

  In order to eliminate such difficulties, Patent Document 1 provides a displacement sensor that detects deformation of the wafer being cooled, and adjusts the pressure and the height of the wafer while monitoring the warpage of the wafer being cooled. Like to do.

JP 2009-182235 A

  Currently, as described in Patent Document 1, the cooling technology is progressing until the wafer warpage during cooling can be suppressed. However, even if the warping of the wafer being cooled can be suppressed, the wafer being cooled shrinks. For this reason, when the wafer is contracted, the back surface of the wafer rubs against the cooling plate and the wafer support pins, and minute scratches such as micro scratches are generated on the back surface of the wafer.

  To date, minute scratches on the backside of the wafer have not been a problem. However, with the miniaturization of semiconductor devices, it has become clear that defocusing occurs due to minute flaws generated on the back surface of the wafer in the exposure process, resulting in a decrease in yield. The minute scratches generated on the back surface of the wafer generate minute irregularities on the back surface of the wafer. When the film forming process is repeated on the wafer, the film forming gas flows around the back surface to form the film, so that the thin film is gradually deposited on the convex part and the convex part becomes larger. The increased convex portion deteriorates the flatness of the surface of the wafer placed on the exposure stage.

  Minute scratches generated on the back surface can be eliminated by polishing the back surface of the wafer. Further, the growth of the convex portion can be suppressed by cleaning the back surface of the wafer. However, if backside polishing or backside cleaning is not performed, or if backside polishing or backside cleaning cannot be performed in the process, the wafer will leave minute scratches on the backside, and the grown protrusions The process proceeds to the film forming process and the exposure process.

  This invention is made in view of the said situation, and provides the cooling method of the to-be-processed object which can suppress generation | occurrence | production of the crack to a to-be-processed object back surface, a cooling device, and a computer-readable storage medium.

  In order to solve the above-described problem, a cooling method for a target object according to a first aspect of the present invention is a cooling method for a target object that cools a heated target object using a cooling member having a cooling mechanism. (1) The heated object to be processed is placed on an object to be processed supporting pin that supports the object to be processed under a vacuum processing pressure, and the object to be processed is separated from the cooling member. In this state, a cooling gas for cooling the object to be processed is supplied at a first flow rate, and the pressure around the object to be processed is increased to a first pressure higher than the pressure of the vacuum processing to A step of cooling for a first time; and (2) lowering the object support pin and placing the object to be processed on or close to the cooling member, At a second flow rate greater than the flow rate of the first and second pressures around the object to be processed. Further, the second time the workpiece is raised to a second higher pressure than the force comprises a a step of cooling.

  A cooling device according to a second aspect of the present invention includes a container configured to be able to vary an internal pressure between a vacuum processing pressure and atmospheric pressure, and a cooling gas supply for supplying a cooling gas into the container. A cooling mechanism having a mechanism, an exhaust mechanism for exhausting the inside of the container, a cooling mechanism provided in the container for cooling the object to be processed by placing or approaching the object to be processed, and the cooling member The object to be processed is received in a state of protruding from the cooling member, and the object to be processed is placed on or close to the cooling member by descending in a state of receiving the object to be processed. The cooling gas supply mechanism, the cooling mechanism, and the processing object support pin so as to cool the processing object support pin and the processing object according to the cooling method of the processing object according to the first aspect. A control device for controlling To.

  A computer-readable storage medium according to a third aspect of the present invention is a computer-readable storage medium that operates on a computer and stores a control program for controlling a cooling device. Sometimes, the cooling device is controlled so that the cooling method of the object to be processed according to the first aspect is performed.

  According to the present invention, it is possible to provide a cooling method, a cooling device, and a computer-readable storage medium for a target object that can suppress generation of scratches on the back surface of the target object.

The top view which shows roughly an example of the semiconductor manufacturing system which can apply the to-be-processed object cooling method which concerns on one Embodiment of this invention Sectional view showing an example of a load lock unit Sectional drawing which shows an example of the cooling method of the to-be-processed object which concerns on one Embodiment. The time chart according to an example of the cooling method of the to-be-processed object which concerns on one Embodiment Sectional drawing which shows the state which made the semiconductor wafer approach on the mounting surface of a cooling plate Sectional drawing which expands and shows the front-end | tip of a contact part Drawing substitute photograph which shows the state of the back surface after completion | finish of cooling of the silicon wafer cooled according to the cooling method of the to-be-processed object which concerns on one Embodiment Time chart according to the cooling method according to the comparative example Drawing substitute photograph showing the state of the back surface after the cooling of the silicon wafer cooled according to the cooling method according to the comparative example

  Embodiments of the present invention will be described below with reference to the drawings. Note that common parts are denoted by common reference numerals throughout the drawings.

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

  As shown in FIG. 1, the semiconductor manufacturing system includes four vacuum processing units 1, 2, 3, and 4 that perform high-temperature processing such as film formation processing. It is provided corresponding to each of the four sides of the transfer chamber 5 having a hexagonal shape. Load lock units 6 and 7 are provided on the other two sides of the transfer chamber 5, respectively. A loading / unloading chamber 8 is provided on the opposite side of the load lock units 6 and 7 from the transfer chamber 5, and a semiconductor wafer W as an object to be processed is provided on the opposite side of the loading / unloading chamber 8 to the load lock units 6 and 7. Ports 9, 10 and 11 for attaching three FOUPs (Front Opening Unified Pods) are provided. The vacuum processing units 1, 2, 3, and 4 are configured to perform a predetermined vacuum process, for example, a film forming process or an etching process, with a target object placed on a processing plate.

  The vacuum processing units 1 to 4 are connected to the respective sides of the transfer chamber 5 through gate valves G, which are communicated with the transfer chamber 5 by opening the corresponding gate valves G and close the corresponding gate valves G. As a result, the transfer chamber 5 is cut off. 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 connected to the loading / unloading chamber 8 via the second gate valve G2. Has been. The load lock chambers 6 and 7 are communicated with the transfer chamber 5 by opening the first gate valve G1, and are shut off from the transfer chamber by closing the first gate valve G1. 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 that loads and unloads the semiconductor wafer W with respect to the vacuum processing units 1 to 4 and the load lock units 6 and 7 is provided. The transfer device 12 is disposed substantially at the center of the transfer chamber 5, and has two support arms 14 a and 14 b that support the semiconductor wafer W at the tip of a rotatable / extensible / retractable portion 13 that can rotate and expand / contract. These two support arms 14a and 14b are attached to the rotating / extending / contracting portion 13 so as to face opposite directions. The inside of the transfer chamber 5 is maintained at a predetermined degree of vacuum.

  Shutters (not shown) are provided in the three ports 9, 10, 11 for attaching the FOUP F, which are wafer storage containers in the loading / unloading chamber 8, respectively, and the wafers W are accommodated in these ports 9, 10, 11 or An empty hoop F is directly attached, and when it is attached, the shutter is released to communicate with the carry-in / out chamber 8 while preventing intrusion of outside air. An alignment chamber 15 is provided on the side surface of the loading / unloading chamber 8 where the semiconductor wafer W is aligned.

  In the loading / unloading chamber 8, a transfer device 16 for loading / unloading the semiconductor wafer W into / from the FOUP F and loading / unloading the semiconductor wafer W into / from the load lock units 6 and 7 is provided. The transfer device 16 has an articulated arm structure and can run on the rail 18 along the direction in which the hoops F are arranged. The semiconductor wafer W is placed on the hand 17 at the tip of the transfer device 16 and transferred. I do.

  This vacuum processing system has a process controller 20 composed of a microprocessor (computer) that controls each component, and each component is connected to and controlled by the process controller 20. Also connected to the process controller 20 is a user interface 21 comprising a keyboard for an operator to input commands for managing the vacuum processing system, a display for visualizing and displaying the operating status of the plasma processing apparatus, and the like. ing.

  In addition, the process controller 20 causes each component of the vacuum processing system to execute processing according to a control program for realizing various types of processing executed by the vacuum processing system under the control of the process controller 20 and processing conditions. For example, a storage unit 22 that stores a program for forming a film, a film forming recipe related to film forming processing, a transfer recipe related to wafer transfer, a purge recipe related to pressure adjustment in the load lock chamber, and the like is connected. Such various recipes are stored in a 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, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, an arbitrary recipe is called from the storage unit 22 by an instruction from the user interface 21 and is executed by the process controller 20, so that a desired process in the vacuum processing system can be performed under the control of the process controller 20. Processing is performed. Further, the process controller 20 can control the pressure and the height of the wafer W so as to suppress the deformation of the wafer in the process in which the load lock units 6 and 7 perform processing based on the standard purge recipe. It has become.

  FIG. 2 is a cross-sectional view showing an example of the load lock unit 6 (7).

  As shown in FIG. 2, the load lock unit 6 (7) has a container 31 configured so that the internal pressure can be varied between the pressure of the vacuum processing and the atmospheric pressure. A cooling member having a cooling mechanism for cooling the semiconductor wafer W by placing or bringing the wafer W close thereto is provided. In this example, the cooling member is a cooling plate 32, and the cooling plate 32 is provided in the container 31 while being supported by the legs 33.

  An opening 34 that can communicate with the transfer chamber 5 held in vacuum is provided on one side wall of the container 31, and an opening that can communicate with the loading / unloading chamber 8 held at atmospheric pressure is provided on the opposite side wall. 35 is provided. 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 introduction port 37 for introducing a 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 an open / close valve 42, an exhaust speed adjustment valve 43, and a vacuum pump 44 are provided in the exhaust pipe 41. Further, a cooling gas introduction pipe 45 for introducing a cooling gas into the container 31 is connected to the cooling gas introduction port 37, and this cooling gas introduction pipe 45 extends from a cooling gas source 48. An opening / closing valve 46 and a flow rate adjusting valve 47 are provided.

  When the wafer W is transferred to or from the vacuum-side transfer chamber 5, the open / close valve 46 is closed and the open / close valve 42 is opened. In this state, the exhaust speed adjusting valve 43 is adjusted to exhaust the interior of the container 31 through the exhaust pipe 36 by the vacuum pump 44 at a predetermined speed, and the pressure in the container 31 is set to a pressure corresponding to the pressure in the transfer chamber 5. To do. When the pressure in the container 31 becomes a pressure corresponding to the pressure in the transfer chamber 5, the first gate valve G <b> 1 is opened to communicate between the container 31 and the transfer chamber 5. Further, when the wafer W is transported to / from the atmospheric loading / unloading chamber 8, the opening / closing valve 42 is closed and the opening / closing valve 46 is opened. In this state, the flow rate adjusting valve 47 is adjusted to introduce the cooling gas into the container 31 from the cooling gas source 48 through the cooling gas introduction pipe 45. An example of the method for introducing the cooling gas will be described later. When the pressure in the container 31 becomes atmospheric pressure or a pressure corresponding to atmospheric pressure, the second gate valve G2 is opened to connect the container 31 and the loading / unloading chamber 8.

  The opening / closing valve 42, the exhaust speed adjusting valve 43, the flow rate adjusting 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 atmospheric pressure and vacuum. Further, the valve control mechanism 49 is controlled based on a command from the process controller 20.

  A plurality of, for example, nine (only two are shown) wafer support pins 50 for wafer transfer are provided on the cooling plate 32 so as to protrude and retract with respect to the surface of the cooling plate 32, and these wafer support pins 50 are supported. It is fixed to the plate 51. Then, the wafer support pins 50 are moved up and down via the support plate 51 by moving the rod 52 up and down by a drive mechanism 53 such as a motor whose height can be adjusted. Reference numeral 54 is a bellows.

  A cooling medium flow path 55 is formed in the cooling plate 32 as a cooling mechanism, and a cooling medium introduction pipe 56 and a cooling medium discharge pipe 57 are connected to the cooling medium flow path 55, and a cooling medium (not shown) It is possible to cool the wafer W mounted by passing a cooling medium such as cooling water from the supply unit.

  The process controller 20 also controls the load lock unit 6 (7), controls the valve control mechanism 49 and the drive mechanism 53 according to the process recipe, and controls the pressure in the container 31 and the height position of the wafer W. It is like that.

  Next, the cooling method of the to-be-processed object which concerns on one Embodiment of this invention is demonstrated.

  3A to 3C are cross-sectional views showing an example of a method for cooling an object to be processed according to an embodiment of the present invention, and FIG. 4 follows an example of the method for cooling an object to be processed according to an embodiment of the present invention. It is a time chart. 3A to 3C, the illustration of the container 31, the gate valves G1, G2, and the like is omitted.

  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 transfer chamber 5. In this example, the pressure used when processing in the vacuum processing units 1 to 4 varies depending on the process, but the pressure in the transfer chamber 5 is substantially constant, for example, several Torr. This is called the vacuum processing pressure. Further, the wafer support pins 50 are raised and protruded from the mounting surface 32 a of the cooling plate 32.

  Next, as shown in FIGS. 3B and 4, the gate valve G <b> 1 is opened, and the semiconductor wafer processed in any one of the vacuum processing units 1 to 4 from the transfer chamber 5 and heated to about 300 ° C. to 500 ° C., for example. W is carried into the container 31 and placed on the wafer support pins 50. Next, with the gate valve G1 closed, the semiconductor wafer W is separated from the mounting surface 32a of the cooling plate 32, and a cooling gas is slowly supplied into the container 31 at a flow rate of, for example, 3000 sccm for about 5 seconds. The pressure inside 31, that is, the pressure around the semiconductor wafer W is slightly increased to a pressure of 50 Torr (6650 Pa) or less exceeding the pressure of the vacuum processing (slow purge 1 in FIG. 4). In this example, the state in which the semiconductor wafer W is separated from the mounting surface 32a and the wafer support pins 50 are not lowered is the state in which the wafer support pins 50 have received the semiconductor wafer W. In this state, the distance L1 between the semiconductor wafer W and the placement surface 32a is, for example, about 20 mm.

  Further, in this example, the supply of the cooling gas is stopped while the wafer support pins 50 receive the semiconductor wafer W (the valve 46 in FIG. 4 is closed). In this state, hold for about 5 seconds. Note that this standby step of holding 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 in a state where the semiconductor wafer W is separated from the mounting surface 32a. Thereby, a slow heat exchange is generated between the semiconductor wafer W and the cooling gas for several seconds from the start of cooling. Due to the slow heat exchange, the heated semiconductor wafer W is slowly cooled.

  The semiconductor wafer W contracts when cooling is started. In this example, a small amount of cooling gas is slowly supplied at the start of cooling (time T1 in FIG. 4). Thereby, the shrinkage start speed of the semiconductor wafer W at the start of cooling can be made as close to zero as possible. By making the shrinkage start speed as close to zero as possible, “rubbing” between the back surface of the semiconductor wafer W and the contact portions 50a of the wafer support pins 50 when the semiconductor wafer W starts to shrink can be reduced.

  Further, for a few seconds after the start of cooling, the wafer support pins 50 are not lowered and the semiconductor wafer W is not moved. For several seconds from the start of cooling, the temperature of the semiconductor wafer W is still high. The high-temperature semiconductor wafer W is considered to be more easily scratched than the low-temperature semiconductor wafer W. For this reason, the wafer support pins 50 are not lowered for a few seconds from the start of cooling, and no mechanical vibration is applied to the semiconductor wafer W. Furthermore, if the pressure increase speed in the container 31 is too fast, the semiconductor wafer W held on the wafer support pins 50 may be displaced, so this pressure increase speed is about the same as the vacuum processing pressure (for example, several Torr). Is desirable, for example, 2 to 9 Torr / sec, more preferably 3 to 5 Torr / sec. Thereby, unnecessary “rubbing” between the back surface of the semiconductor wafer W and the contact portion 50a can be suppressed within a few seconds from the start of cooling.

  Next, as shown in FIGS. 3C and 4, when the temperature of the semiconductor wafer W is lowered to some extent, the wafer support pins 50 are lowered, and the semiconductor wafer W is placed on the placement surface 32 a of the cooling plate 32. Let them be in close proximity.

  The close state means that the semiconductor wafer W protrudes from the mounting surface 32a on the mounting surface 32a (see FIG. 5A), or a state closer to the mounting surface 32a than the state shown in FIG. In addition, a fixed support pin 32b is provided, and the semiconductor wafer W is slightly lifted from the mounting surface 32a (see FIG. 5B). The distance L2 between the semiconductor wafer W and the mounting surface 32a when the semiconductor wafer W is slightly floated using the support pins 32b is, for example, about 0.5 mm. Next, with the semiconductor wafer W placed on or placed close to the placement surface 32a of the cooling plate 32, the cooling gas is supplied into the container 31 at a flow rate of about 15 sccm, for example, at the same flow rate as the previous slow purge 1. Slow supply is performed for 2 seconds, and the pressure in the container 31 is increased to a pressure of 100 Torr (13330 Pa) or less (slow purge 2 in FIG. 4). Next, the flow rate of the cooling gas is increased to, 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 increased to atmospheric pressure or a pressure in the vicinity of atmospheric pressure. Note that the pressure near atmospheric pressure is, for example, a pressure in a range of ± 5% with respect to atmospheric pressure. Thereby, the semiconductor wafer W is cooled to a temperature at which the semiconductor wafer W is not oxidized by the cooling plate 32 and the cooling gas, or a temperature at which the semiconductor wafer does not melt the resin wafer cassette, or a room temperature.

  Furthermore, in the example of the method for cooling the object to be processed according to the embodiment, the wafer support pins 50 are also devised. As described with reference to FIG. 3B, when cooling of the semiconductor wafer W is started, the semiconductor wafer W contracts. Due to the shrinkage, the back surface of the semiconductor wafer W rubs against the contact portions 50 a of the wafer support pins 50.

  Therefore, in this example, the Vickers hardness of at least the contact portion 50a of the wafer support pin 50 that contacts the object to be processed, in this example, the semiconductor wafer W, is set to be equal to or less 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.

  Thus, by using at least the material of the contact portion 50a as quartz, the Vickers hardness of the contact portion 50a can be equal to or less than the Vickers hardness of the back surface of the silicon wafer. Thereby, generation | occurrence | production of the damage resulting from the rubbing with the back surface of a silicon wafer and the contact part 50a can further be suppressed.

  Furthermore, in this example, the shape of the tip of the contact portion 50a is also devised. FIG. 6 is an enlarged cross-sectional view of the tip 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 spherical, the back surface of the semiconductor wafer W can be made less likely to be scratched than when the tip of the contact portion 50a is flat.

  Further, when the spherical curvature is tight, the tip of the contact portion 50a becomes acute, and the back surface of the semiconductor wafer W is easily scratched. Therefore, in this example, the curvature radius of the spherical surface is set to 5 mm. Thereby, the generation | occurrence | production of the damage | wound to the back surface of the semiconductor wafer W can be suppressed more compared with the case where the curvature radius of a spherical surface is 2 mm, for example.

  Also, if the spherical curvature is gentle, the tip of the contact portion 50a approaches a flat surface, and the back surface of the semiconductor wafer W is easily scratched. From this viewpoint, the upper limit of the radius of curvature of the spherical surface may be about 10 mm.

  In summary, the radius of curvature of the spherical surface at the tip of the contact portion 50a is preferably 5 mm or more and 10 mm or less.

  FIG. 7 shows a state of the back surface of the silicon wafer cooled according to the cooling method of the object to be processed according to the above-described embodiment after the cooling is completed.

  As shown in FIG. 7, the state of the back surface of the silicon wafer is such that contact marks are observed, and minute scratches such as micro scratches are not observed.

  Further, as a comparative example, the contact portion of the wafer support pin is cooled according to the time chart shown in FIG. 8 and the material of the contact portion of the wafer support pin is alumina (harder than the Vickers hardness on the back surface of the silicon wafer), and the shape of the tip of the contact portion is flat FIG. 9 shows the state of the back surface after cooling is completed.

  As shown in FIG. 9, the scratch on the back surface of the silicon wafer as a comparative example is seen as a micro scratch.

  As described above, according to the method for cooling an object to be processed according to the embodiment, the heated semiconductor wafer W is placed on the wafer support pins 50 under the pressure of vacuum processing, and the semiconductor wafer W is removed from the cooling plate 32. By slowly supplying the cooling gas in a separated state, the semiconductor wafer W is slowly cooled for a few seconds from the start of cooling. Thereby, rapid shrinkage of the semiconductor wafer W at the start of cooling of the semiconductor wafer W can be suppressed, and generation of scratches on the back surface of the semiconductor wafer W can be suppressed.

  Furthermore, the wafer support pins 50 are not moved during the process for several seconds after the start of cooling. By further providing this configuration, it is possible to prevent mechanical vibration from being applied to the semiconductor wafer W for a few seconds after the start of cooling when the semiconductor wafer W is still hot. Thereby, the generation | occurrence | production of the damage | wound to the back surface of the semiconductor wafer W can be suppressed in the period when the semiconductor wafer W considered that it is easy to be damaged is high temperature.

  Further, the material of the contact portion 50a of the wafer support pin 50 is set to be equal to or lower than the Vickers hardness of the back surface of the semiconductor wafer W. By further including this configuration, generation of scratches on the back surface of the semiconductor wafer W can be further suppressed.

  Furthermore, the shape of the tip of the contact portion 50a is a spherical surface. By further including this configuration, generation of scratches on the back surface of the semiconductor wafer W can be further suppressed.

  As described above, according to one embodiment of the present invention, a cooling method for a target object that can suppress the occurrence of scratches on the back surface of the target object, a cooling device that can implement this cooling method, and cooling according to the cooling method described above. A computer-readable storage medium capable of controlling the apparatus can be provided.

  In addition, this invention is not limited to the said one Embodiment, A various deformation | transformation is possible. Further, the embodiment of the present invention is not the only one described above.

  For example, in the above-described embodiment, the multi-chamber type vacuum processing system provided with four vacuum processing units and two load lock units has been described as an example. The load lock unit may be attached to the vacuum processing unit.

  In the above embodiment, the processing time is defined as shown in FIG. 4, but 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) A heated object to be processed is placed on a target object supporting pin that supports the object to be processed under the pressure of vacuum processing, and the object to be processed is separated from the cooling member. Supplying a cooling gas for cooling the substrate at a first flow rate, raising the pressure around the object to be processed to a first pressure higher than the pressure of the vacuum process, and cooling the object to be processed for a first time (2) ) With the object supporting pin lowered, the object to be processed is placed on or placed close to the cooling member, and the cooling gas is supplied at a second flow rate higher than the first flow rate. A step of raising the ambient pressure to a second pressure higher than the first pressure and further cooling the object to be processed for a second time.
In addition, the present invention can be modified as appropriate without departing from the spirit of the present invention.

  1-4; Vacuum processing unit, 5; Transfer chamber, 6, 7; Load lock unit, 8; Loading / unloading chamber, 12, 16; Transfer device, 20; Process controller, 31; Container, 32; Exhaust port 37; Cooling gas inlet port 45; Cooling gas inlet pipe 48; Cooling gas source 50; Wafer support pin 50a; Contact portion 55; Coolant flow path W; Wafer

Claims (12)

A method for cooling an object to be processed, wherein the object to be processed is cooled using a cooling member having a cooling mechanism.
(1) The heated object to be processed is placed on an object to be processed supporting pin that supports the object to be processed under a vacuum processing pressure, and the object to be processed is separated from the cooling member. A cooling gas for cooling the object to be processed is supplied at a first flow rate, and the pressure around the object to be processed is increased to a first pressure higher than the pressure of the vacuum processing to thereby cause the object to be processed to be a first pressure. Cooling time,
(2) In a state where the object to be processed support pin is lowered and the object to be processed is placed on or close to the cooling member, the cooling gas is supplied at a second flow rate higher than the first flow rate. Supplying and raising the pressure around the object to be processed to a second pressure higher than the first pressure to further cool the object to be processed for a second time;
A method for cooling an object to be processed, comprising:   The method for cooling an object to be processed according to claim 1, wherein the object support pin is not moved during the step (1).   The to-be-processed object according to claim 1 or 2, wherein the first pressure exceeds the pressure of the vacuum processing and is 50 Torr or less, and the second pressure is an atmospheric pressure or a pressure in the vicinity of the atmospheric pressure. Body cooling method.   The state in which the object to be processed is separated from the cooling member is a state in which the object to be processed is received by the object to be processed support pin. The cooling method of the to-be-processed object of description.   5. The Vickers hardness of at least a contact portion of the object to be processed support pin with the object to be processed is set to be equal to or less than the Vickers hardness of the back surface of the object to be processed. The method for cooling an object to be processed according to the item.   6. The object to be processed according to claim 5, wherein when the object to be processed is a silicon wafer, a material of at least a contact portion of the object to be processed support pin with the object to be processed is quartz. Cooling method.   The shape of the tip of the contact portion of the workpiece support pin with the workpiece is a spherical surface, and the radius of curvature of the spherical surface is 5 mm or more and 10 mm or less. The method for cooling an object to be processed according to claim 1. A container configured to be able to vary the internal pressure between the vacuum processing pressure and the atmospheric pressure;
A cooling gas supply mechanism for supplying a cooling gas into the container;
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 approaching the object to be processed;
The cooling member is provided so as to be able to project and retract, receives the object to be processed in a state of protruding from the cooling member, and descends in a state of receiving the object to be processed, thereby removing the object to be processed from the cooling member. To-be-processed object support pins placed on or in proximity to,
The cooling gas supply mechanism, the cooling mechanism, and the object to be processed support pin so as to cool the object to be processed according to the method for cooling an object to be processed according to any one of claims 1 to 4. A control device for controlling
A cooling device comprising:   9. The cooling device according to claim 8, wherein a Vickers hardness of at least a contact portion of the object supporting pin with the object to be processed is equal to or less than a 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, a material of at least a contact portion of the object to be processed supporting pin with the object to be processed is quartz.   The cooling device according to any one of claims 8 to 10, wherein a shape of a contact portion of the object support pin with the object to be processed is a spherical surface. A computer-readable storage medium that operates on a computer and stores a control program for controlling the cooling device,
5. The computer-readable computer program according to claim 1, wherein the control program controls the cooling device so that the cooling method of the object to be processed according to any one of claims 1 to 4 is performed during execution. Storage medium.