JP2009049061A - Device and method for processing semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for processing a semiconductor wafer avoiding wafer contamination and efficiently cooling a mounting pedestal of the semiconductor wafer after heating, thereby improving the throughput. <P>SOLUTION: The device 1 for processing the semiconductor wafer includes: a chamber 3 for housing the semiconductor wafer W; and the wafer mounting pedestal 5 provided in the chamber 3 and having a mounting surface 7 for mounting the semiconductor wafer W. The device 1 for processing the semiconductor wafer processes the semiconductor wafer W in the chamber 3 by heating the mounting surface 7, while heating the semiconductor wafer W. The device 1 also includes a mounting-surface-cooling part 21 for cooling the mounting surface 7, and the mounting-surface-cooling part 21 has a cooling gas path 23 embedded in the wafer mounting pedestal 5 to get the gas for cooling through. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor wafer processing apparatus and a semiconductor wafer processing method for processing a semiconductor wafer in a chamber.

Conventionally, as a technique in such a field, for example, a dry etching apparatus described in Patent Document 1 below is known. In this type of semiconductor wafer processing, in order to perform processing while heating the semiconductor wafer, the mounting table on which the wafer is mounted may be heated by a heater or the like. In such a case, in order to increase the throughput, it is required to increase the temperature increase rate and the temperature decrease rate of the mounting table. The rate of temperature increase can be improved relatively easily by increasing the heater capacity, but the rate of temperature decrease is not easy. For example, although it depends on the heat capacity of the mounting table, the cooling rate is about 1 to 2 ° C./min in natural cooling. come. Therefore, in order to increase the temperature lowering rate, a method of cooling the mounting table after heating by blowing gas has been considered.
JP-A-9-283505

  However, in such a cooling system, since a cooling gas is introduced into the chamber, contamination of the chamber and the wafer becomes a problem even when an inert gas is used. In order to prevent such contamination, it is necessary to install a high-density filter or the like in order to remove impurity fine particles (particles) contained in the inert gas introduced into the chamber, which complicates the apparatus. End up. Moreover, even if a high density filter is used, it is difficult to completely remove the mixed particles. Moreover, such a system is not necessarily a system with good cooling efficiency, and it also falls into a vicious circle in which contamination increases with increasing gas flow rate.

  Further, as another method for cooling the mounting table, a water cooling method in which a cooling water is circulated by providing a water cooling pipe on the mounting table may be considered. However, if water is supplied when the mounting table is at a high temperature, the water may boil and the water cooling tube may be damaged. Therefore, the water is supplied after the temperature is lowered to a certain level (about 200 ° C.). That is, when the mounting table is heated to a high temperature of 200 ° C. or higher, natural cooling is substantially achieved up to 200 ° C. Moreover, even if water is supplied after the temperature is lowered to 200 ° C., measures such as strengthening the water-cooled tube member corresponding to the vapor pressure of water are required. In addition, when the mounting table has a rotating mechanism for rotating the semiconductor wafer, it is necessary to use a rotary joint or the like for connecting the water-cooled pipes, and it also costs money for countermeasures against water leakage. A big influence. In addition, when the mounting table is heated again, it is necessary to completely remove water from the water-cooled tube, and the throughput is reduced accordingly.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor wafer processing apparatus and a semiconductor wafer processing method capable of avoiding the occurrence of wafer contamination, efficiently cooling a semiconductor wafer mounting table after heating, and improving throughput. To do.

  A semiconductor wafer processing apparatus of the present invention includes a chamber for storing a semiconductor wafer and a wafer mounting table provided in the chamber and having a mounting surface for mounting the semiconductor wafer, and heating the mounting surface. A semiconductor wafer processing apparatus for processing a semiconductor wafer in a chamber while heating the semiconductor wafer includes a mounting surface cooling unit that cools the mounting surface. The mounting surface cooling unit is built in the wafer mounting table and is cooled. And a cooling gas passage through which the gas is passed.

  In this semiconductor wafer processing apparatus, processing is performed while heating the semiconductor wafer, so that the mounting surface of the wafer mounting table is heated. After the processing of the semiconductor wafer, the placement surface is cooled again by the placement surface cooling unit. Since the mounting surface cooling unit has a cooling gas passage built in the wafer mounting table, the mounting table is efficiently cooled by the cooling gas passing through the cooling gas passage, and the temperature of the mounting surface is efficiently increased. It drops well. Therefore, after the semiconductor wafer is heated, the temperature of the mounting table can be quickly lowered, so that throughput in processing is improved. Further, since such a cooling gas passes through the cooling gas passage built in the wafer mounting table, the gas does not flow through the chamber, and contamination of the chamber and the semiconductor wafer can be avoided.

  The cooling gas passage preferably extends radially from the center of the wafer mounting table along the mounting surface. According to this configuration, since the cooling gas flows radially along the wafer mounting table, the mounting surface can be uniformly cooled as a whole.

  Further, the cooling gas may be nitrogen or helium. Furthermore, the cooling efficiency can be further increased by using nitrogen or helium gas cooled to room temperature or lower.

  In the semiconductor wafer processing method of the present invention, a semiconductor wafer is placed on a placement surface of a wafer placement table provided in the chamber in a chamber for storing the semiconductor wafer, and the placement surface is heated. In a semiconductor wafer processing method for processing a semiconductor wafer while heating the semiconductor wafer, the semiconductor wafer processing method includes a mounting surface cooling process for cooling the heated mounting surface, and in the mounting surface cooling process, a cooling built in the wafer mounting table is provided. A cooling gas is passed through the gas passage.

  In this semiconductor wafer processing method, processing is performed while heating the semiconductor wafer, so that the mounting surface of the wafer mounting table is heated. After the processing of the semiconductor wafer, the placement surface is cooled again by the placement surface cooling step. In the mounting surface cooling step, the mounting table is efficiently cooled by the cooling gas passing through the cooling gas passage built in the wafer mounting table, and the temperature of the mounting surface is efficiently reduced. Further, since such a cooling gas passes through the cooling gas passage built in the wafer mounting table, the gas does not flow through the chamber, and contamination of the chamber and the semiconductor wafer can be avoided.

  According to the semiconductor wafer processing apparatus and the semiconductor wafer processing method of the present invention, it is possible to avoid the occurrence of wafer contamination, efficiently cool the semiconductor wafer mounting table after heating, and improve the throughput.

  Hereinafter, preferred embodiments of a semiconductor wafer processing apparatus and a semiconductor wafer processing method according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the semiconductor wafer processing apparatus 1 includes a chamber 3 defined by an outer shell 3 a and an iron wafer mounting table 5 provided in the chamber 3 and having a circular planar shape. ing. In this apparatus 1, a semiconductor wafer W is placed on a placement surface 7 formed as an upper surface of the wafer placement table 5. Then, the mounting surface 7 is heated by a heater 9 built in the wafer mounting table 5 and positioned immediately below the mounting surface 7. With such a configuration, predetermined wafer processing can be performed on the semiconductor wafer W while the semiconductor wafer W on the mounting surface 7 is heated in the chamber 3. Here, the predetermined wafer processing includes CVD (Chemical Vapor Deposition) performed in a vacuum or normal pressure chamber or RIE (Reactive ion etching) performed in a high vacuum chamber. Processing of the semiconductor wafer W is included.

  Further, the wafer mounting table 5 has a rotating mechanism and rotates horizontally around a vertical axis passing through the center of the mounting surface 7. In addition, power from the power supply unit 11 to the heater 9 is supplied via the rotary electrode 15. With this configuration, the apparatus 1 can perform the wafer processing while rotating the semiconductor wafer W.

  In addition, the apparatus 1 includes a cooling unit 21 for cooling the wafer mounting table 5 and the mounting surface 7 that have become high temperature after heating the wafer W by using a cooling gas. Note that an inert gas such as nitrogen or helium is used as the cooling gas. The cooling unit 21 is incorporated in the wafer mounting table 5 and is located immediately below the heater 9, and includes a number of cooling gas passages 23 extending radially from the center of the wafer mounting table 5 in the horizontal direction. The cooling gas passage 23 has an upper passage 23a that is elongated in the radial direction of the wafer mounting table 5, and a lower passage 23a that communicates with the tip of the upper passage 23a and extends in parallel immediately below the upper passage 23a. Since the cooling gas passage 23 is not connected to the chamber 3 and is provided separately, the cooling gas does not flow through the chamber, and contamination of the chamber and the semiconductor wafer can be avoided. The upper passage 23a causes the cooling gas to flow from the center of the wafer mounting table 5 toward the peripheral portion, and the lower passage 23b causes the cooling gas to flow from the peripheral portion toward the center. Furthermore, the cooling unit 21 includes a gas introduction path 25 for introducing a cooling gas into the upper passage 23a and a gas discharge path 27 for discharging the cooling gas from the lower passage 23b. The gas introduction path 25 extends along a vertical axis passing through the center of the mounting surface 7, and a gas discharge path 27 is provided so as to surround the periphery of the gas introduction path 25.

  With this configuration of the cooling unit 21, when the cooling gas is introduced from the gas supply unit 29 into the gas introduction path 25 through the gas introduction port 25a, the cooling gas moves from the center toward the outside through the upper passages 23a arranged radially. Pass through. Thereafter, the cooling gas flows from the peripheral portion of the wafer mounting table 5 toward the center through the lower passages 23b, passes through the gas discharge path 27, and is discharged from the gas discharge port 27a. Further, the cooling gas is discharged from the exhaust port 28 to the outside air via an exhaust processing device (not shown). As described above, the cooling gas flows through the cooling gas passage 23 inside the wafer mounting table 5, whereby the wafer mounting table 5 and the mounting surface 7 are efficiently cooled.

  Based on such a configuration of the apparatus 1, when the semiconductor wafer W to be processed is introduced into the chamber 3 and placed on the placement surface 7, the heater 9 is moved on the placement surface 5 by the power from the power supply unit 11. The semiconductor wafer W is heated. Further, while the wafer mounting table 5 rotates horizontally, the above-described wafer processing is performed in the chamber 3, and the semiconductor wafer W is processed. Thereafter, when the processed semiconductor wafer W is removed from the mounting surface 5, a cooling gas is introduced into the gas introduction path 25, and the cooling gas passes through the upper passages 23a and the lower passages 23b arranged in a radial pattern. . Then, the heat of the wafer mounting table 5 at a high temperature is removed by the cooling gas, and the wafer mounting table 5 and the mounting surface 7 are efficiently cooled.

  As described above, after the semiconductor wafer W is heated and processed, the temperature of the mounting surface 7 that has reached a high temperature can be quickly lowered to the initial state, so that the throughput in wafer processing is improved. Further, since the cooling gas passes through the inside of the wafer mounting table 5, no gas flows through the chamber 3, and contamination of the chamber 3 and the semiconductor wafer W can be avoided. In addition, since the plurality of cooling gas passages 23 are radially expanded in parallel with the placement surface 7, each part of the placement surface 7 is cooled uniformly.

  Further, since gas is used as a coolant for cooling the wafer mounting table 5, strict airtightness is not required for connection between the gas supply unit 29 and the gas inlet 25a, and a rotary joint or the like is omitted. A simple one such as the simple joint 31 can be used. In addition, the piping for the refrigerant is easier as compared with the case where a liquid is used as the refrigerant. In addition, the flow of the cooling gas in the cooling unit 21 may be a flow opposite to the above. That is, the cooling gas may be introduced from the gas discharge port 27a side, flowed in the order of the lower passage 23b and the upper passage 23a, and discharged to the gas introduction port 25a side.

  Subsequently, in order to compare with the semiconductor wafer processing apparatus 1 described above, other cooling methods for the wafer mounting table and the mounting surface in the semiconductor wafer processing apparatus will be examined.

  First, as shown in FIGS. 4 and 5, the wafer mounting table 105 of the semiconductor wafer processing apparatus 101 includes a cylindrical cooling gas retention space 123 formed immediately below the heater 9. The cooling gas is introduced into the cooling gas retention space 123 from the gas introduction path 25 located at the center, and the cooling gas is discharged from the gas discharge pipe 127, whereby the wafer mounting table 105 is cooled. In this semiconductor wafer processing apparatus 101, components that are the same as or equivalent to those in the semiconductor wafer processing apparatus 1 are denoted by the same reference numerals in the drawings, and description thereof is omitted.

  According to the configuration of the apparatus 101, the cooling gas stagnant space 123 is located away from the gas introduction path 25 and the gas discharge pipe 27, and the location where the cooling gas stagnates and smooth flow is not performed. Inefficient. Since gas has a lower heat transfer property than liquid, such a stagnation of gas becomes a problem when gas is used as a refrigerant. On the other hand, the semiconductor wafer processing apparatus 1 described above has a plurality of elongate cooling gas passages 23 arranged radially instead of the cooling gas retention space 123, so that the stagnation of the cooling gas hardly occurs and high cooling is achieved. It is excellent in that efficiency is obtained.

  As a possible cooling system, there is a water cooling system in which cooling water is circulated in the wafer mounting table. For example, it is conceivable to use water as a refrigerant instead of the cooling gas of the semiconductor wafer processing apparatus 1 described above. However, in this case, if water is supplied when the wafer mounting table 5 is at a high temperature, the water may boil and the wafer mounting table 5 may be damaged. Therefore, the water is supplied after the temperature is lowered to a certain level (about 200 ° C.). It will be. That is, in the wafer processing, when the wafer mounting table 5 is heated to a high temperature of 200 ° C. or higher, the temperature is naturally cooled to 200 ° C. Further, even when water is supplied after the temperature is lowered to 200 ° C., measures such as strengthening the mounting table 5 member against the vapor pressure of water are required.

  Further, when the wafer mounting table 5 has a rotation mechanism, a high airtightness is required for connection of the water supply unit, so that it is necessary to use a rotary joint or the like and there is a cost for countermeasures against water leakage. The equipment cost is greatly affected. Further, when the mounting surface 7 is heated again, it is necessary to completely remove water from the wafer mounting table 5, and the throughput is reduced accordingly. In contrast, in the semiconductor wafer processing apparatus 1 described above, since gas is used as the refrigerant, the above-described problems can be avoided, measures such as strengthening the mounting table 5 member are not required, and throughput can be improved. It is excellent in that it can.

  Next, as shown in FIG. 6, the semiconductor wafer processing apparatus 201 using still another cooling method includes a gas ejection pipe 223 provided above the wafer mounting table 205. The cooling gas sent from the gas supply unit 29 to the gas ejection pipe 223 is ejected downward from the ejection hole 223 a and blown onto the placement surface 7. Then, the wafer mounting table 5 is cooled by the sprayed cooling gas. Thereafter, the cooling gas is discharged from the exhaust port 228 to the outside air via an exhaust processing device (not shown). In this semiconductor wafer processing apparatus 201, the same or equivalent components as those in the semiconductor wafer processing apparatus 1 are denoted by the same reference numerals in the drawing and description thereof is omitted.

  In such a semiconductor wafer processing apparatus 201, since a cooling gas is introduced into the chamber 3, contamination of the chamber 3 and the wafer W becomes a problem even if an inert gas is used. In order to prevent such contamination, it is necessary to install a high-density filter or the like in order to remove particles contained in an inert gas or the like introduced into the chamber, which complicates the apparatus. Further, such a method is not necessarily an efficient method, and it also falls into a vicious circle in which contamination increases with increasing gas flow rate. It is necessary to install a high-density filter or the like, which complicates the apparatus. Moreover, even if a high density filter is used, it is difficult to completely remove the mixed particles. On the other hand, in the semiconductor wafer processing apparatus 1 described above, since the cooling gas passes through the cooling gas passage 23 built in the wafer mounting table 5, no gas flows in the chamber 3, And is excellent in that contamination of the semiconductor wafer W can be avoided.

  Next, an experiment conducted by the present inventors for confirming the effect of the semiconductor wafer processing apparatus 1 will be described. Here, in the semiconductor wafer processing apparatuses 1 and 201, an experiment was performed to cool the wafer mounting tables 5 and 205 heated to respective temperatures (200 ° C., 300 ° C., and 500 ° C.). Nitrogen (normal temperature) and helium (normal temperature) were used as the cooling gas, and nitrogen was cooled at two gas flow rates (50 L / min and 100 L / min). Then, the time for the temperature of the wafer mounting table to drop to 50 ° C. was measured, and the number of particles on the semiconductor wafer after the temperature reduction was further measured. For comparison, the same experiment was performed when the wafer mounting table was naturally cooled.

  As shown in the experimental results shown in the table of FIG. 7, the wafer mounting table can be cooled in the processing apparatus 1 in 1/3 time compared to the processing apparatus 201. Therefore, according to the processing apparatus 1, it was confirmed that the throughput can be improved. In addition, the number of particles (diameter 0.05 μm or more) on the wafer W after the temperature of the wafer mounting table was lowered was the same level as that of natural cooling, and it was confirmed that the processing apparatus 1 can avoid contamination of the wafer W.

It is sectional drawing which shows embodiment of the semiconductor wafer processing apparatus which concerns on this invention. It is II-II sectional drawing in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is sectional drawing which shows the semiconductor wafer processing apparatus with which another cooling system is used. It is VV sectional drawing in FIG. It is sectional drawing which shows the semiconductor wafer processing apparatus with which another cooling system is used. It is a table | surface which shows the result of the experiment which the present inventors performed in order to confirm the effect of a semiconductor wafer processing apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer processing apparatus, 3 ... Chamber, 5 ... Wafer mounting table, 7 ... Mounting surface, 21 ... Mounting surface cooling part, 23 ... Cooling gas passage, W ... Semiconductor wafer.

Claims (4)

A chamber for storing a semiconductor wafer; and a wafer mounting table provided in the chamber and having a mounting surface on which the semiconductor wafer is mounted, and heating the semiconductor wafer by heating the mounting surface. In a semiconductor wafer processing apparatus for processing the semiconductor wafer in the chamber,
A mounting surface cooling unit for cooling the mounting surface,
The mounting surface cooling section described above is
A semiconductor wafer processing apparatus comprising a cooling gas passage which is built in the wafer mounting table and allows a cooling gas to pass therethrough. The cooling gas passage is
The semiconductor wafer processing apparatus according to claim 1, wherein the semiconductor wafer processing apparatus extends radially from the center of the wafer mounting table along the mounting surface.   The semiconductor wafer processing apparatus according to claim 1, wherein the cooling gas is nitrogen or helium. In a chamber for storing a semiconductor wafer, the semiconductor wafer is placed on a placement surface of a wafer placement table provided in the chamber, and the semiconductor wafer is heated while heating the placement surface. In a semiconductor wafer processing method for processing a wafer,
A placement surface cooling step for cooling the heated placement surface,
In the mounting surface cooling process described above,
A semiconductor wafer processing method, wherein a cooling gas is passed through a cooling gas passage built in the wafer mounting table.

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