JPH0758092A - Reduced pressure treating apparatus - Google Patents

Abstract

PURPOSE:To provide a reduced pressure treating apparatus having a structure which can prevent the dew condensation occurring in a body to be treated after treatment. CONSTITUTION:A body to be treated 12 is treated with a heater 90 before the temperature of the body to be treated 12 reaches the normal temperature before the body to be treated 12, which is maintained at the low temperature state in the pressure-reduced atmosphere and etched, returns to an atmospheric ambience. Therefore, the moisture in gas stagnating on the surface of the body to be treated 12, whose etching is finished, is evaporated. Thus, the change in surface state of the body to be treated when the moisture in the gas is liquified in the atmospheric ambience can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduced pressure processing apparatus,
In particular, the present invention relates to a dew condensation preventing mechanism for a target object.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing process, a thin film is formed on a surface of an object to be processed such as a semiconductor wafer or the thin film is removed. A processing apparatus such as a low pressure CVD apparatus, a sputtering apparatus or an etching apparatus is used for such a step.

For example, in the etching process, the temperature of the object to be processed may rise due to collision energy of active species and the like. For this reason, conventionally, the object mounting base has been cooled to perform etching at a constant low temperature.

Further, in the above-mentioned etching treatment, as the miniaturization and high integration of integrated circuits are promoted, it is strongly desired to secure a high selection ratio and a high anisotropy with a base material. .

Under such a circumstance, recently, a so-called wafer is cooled to an ultra-low temperature of about -150 ° C. using liquid nitrogen, for example, and a depressurized state is set and an etching process is performed. , A low temperature etching method has been developed.

According to this low-temperature etching process, when etching a polysilicon or a silicon oxide film, for example, the selectivity with respect to the underlying layer can be greatly increased as compared with the conventional method, and further, it is different. Since the orientation can be sufficiently ensured, for example, when forming a contact hole, it is possible to form a sharp hole close to 90 ° in which the angle of the side wall of the hole is not rounded.

Therefore, as an apparatus for performing the above-mentioned etching process, a cooling means for flowing liquid nitrogen, for example, as a cooling medium is provided below a mounting table for holding a wafer, that is, a so-called susceptor, and this cooling means is provided. A temperature adjustment heater is provided between the susceptor and the susceptor, and the amount of heat generated by the heater is changed to control the cooling heat supplied from the cooling means to the wafer to control the wafer temperature.

[0008]

By the way, an object to be processed in a low temperature atmosphere is returned to room temperature by being carried out into the atmosphere after completion of the processing, but the object to be processed is returned to the room temperature. Moisture in the gas staying on the body surface may be condensed. That is, the processed object is transferred from the process chamber to the load lock chamber and is switched to the atmospheric pressure atmosphere at this position. Therefore, the moisture in the gas that has accumulated on the surface of the object to be processed in the low temperature atmosphere is easily liquefied in the atmospheric pressure atmosphere, and dew condensation is likely to occur. In particular, when a corrosive gas such as chlorine gas is used as the process gas, when the moisture in the chlorine gas that has accumulated on the surface of the object to be processed is liquefied, dew condensation occurs on the surface of the object to be processed. It may corrode the surface of the body.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a depressurization processing apparatus having a structure capable of preventing the above-mentioned problems in the conventional depressurization processing apparatus, in particular, the dew condensation that occurs on the processed object. is there.

[0010]

In order to achieve this object, in the invention according to claim 1, the object to be processed is decompressed while being cooled on a mounting table in the process chamber, and after the processing,
A depressurization processing apparatus having a structure for carrying out to a load lock chamber, comprising means for heating the object to be processed in either or both of the process chamber and the load lock chamber, and depressurizing the object to be processed. It is characterized in that the temperature of the object to be processed is heated to near room temperature while the temperature is being detected before returning from the atmosphere to the atmospheric pressure.

According to a second aspect of the present invention, in the first aspect, the heating means for the object to be processed is provided in the transfer means for transferring the object to be processed between the process chamber and the load lock chamber. Is characterized by.

According to a third aspect of the present invention, in the first aspect, the heating means heats the processed object in the process chamber, and the object is processed by the mounting table. It is characterized in that it is heated in a state of being pushed up by the pushing-up member.

According to a fourth aspect of the present invention, in any one of the first to third aspects, means for detecting the temperature of the processed object is provided, and the temperature detecting means is provided in the load lock chamber. It is characterized in that it is composed of a contact type temperature sensor provided in the carrying means.

According to a fifth aspect of the present invention, in the third aspect, means for detecting the temperature of the processed object is provided, and the temperature detecting means is provided in the push-up member. I am trying.

According to a sixth aspect of the present invention, the object to be processed is subjected to reduced pressure processing while being cooled on a mounting table in the process chamber,
After the processing, in the depressurization processing apparatus having a structure for carrying out to the load lock chamber, a means for supplying a purge gas into the load lock chamber, and a means for heating the purge gas, the processed object is When being carried out to the load lock chamber, the purge gas is supplied in a heated state until the surface temperature of the object to be processed reaches near room temperature.

[0016]

In the present invention, after the processing, the object to be processed which is switched to the atmospheric pressure atmosphere has the water in the gas accumulated on its surface removed. That is, the object to be processed is heated before switching from the vacuum atmosphere to the atmospheric pressure atmosphere. Therefore, when it is returned to the atmospheric pressure atmosphere, there is no moisture that causes dew condensation on the surface of the object to be treated, so that it is possible to prevent changes in the surface characteristics of the object that may cause liquefaction. You can

Further, in the present invention, water in the gas staying on the surface of the object to be processed is removed in the process chamber or the load lock chamber corresponding to the stage before switching to the atmospheric pressure atmosphere. If the object to be processed is heated by the object-to-be-processed transferring means, the water content can be evaporated during the transfer period between the chambers. Throughput can be improved in comparison.

Furthermore, according to the present invention, the purge gas used to set the inside of the load lock chamber under the atmospheric pressure atmosphere is heated to remove the water contained in the gas remaining on the surface of the object to be processed. You can For this reason,
Since the switching operation to the atmospheric pressure atmosphere and the water removal can be performed together, it is possible to prevent the dew condensation and improve the throughput.

[0019]

Embodiments of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an etching apparatus which is one of the depressurization processing apparatuses according to the present invention. This etching apparatus includes a process chamber 10 for carrying out an etching process and a semiconductor wafer or the like for the process chamber 10. A load-side load lock chamber 30 and a sender 40 that form a target object transfer system, and a load-side load lock chamber 50 and a receiver 6 that configure a target object transfer system.
It is composed of 0 and 0.

The process chamber 10 is for etching an object to be processed (hereinafter referred to as a semiconductor wafer) 12 such as a semiconductor wafer. This process chamber 1
0 is formed in a box shape made of a material that does not react with the processing gas, and an electrode, for example, a lower electrode 14 connected to an elevating mechanism (not shown) is provided below the inside of the chamber 10 so as to be vertically movable. The lower electrode 14 made of a conductive plate on which the semiconductor wafer 12 can be mounted and fixed is subjected to a surface treatment so as not to react with the processing gas, and is formed into, for example, a circle that matches the shape of the semiconductor wafer 12. Further, an upper electrode body 16 forming a parallel plate electrode facing the lower electrode 14 is provided above the inside of the process chamber 10. An upper electrode 18 made of, for example, amorphous carbon is electrically connected to the lower surface of the upper electrode body 16. Then, an etching gas introducing pipe 20 is connected to the upper electrode body 16, diffused by a baffle plate (not shown), and then passes through the upper electrode 18 to uniformly supply the gas onto the semiconductor wafer 12. There is.

In addition, the upper electrode body 16 and the lower electrode 14
Between the high frequency power supply 22 for supplying high frequency power.
Are connected to generate plasma between the electrodes 14 and 18 by the etching gas. The exhaust of the etching gas in the process chamber 10 is performed through the gas exhaust port 24.

As a method of supplying the high frequency power, for example, there is a method of applying a high frequency of 13.56 MHz and a low frequency of 380 KHz to the same electrode. In this case, as shown in FIG. 2, it is general that Rf power supplies 22A and 22B of respective frequencies are provided and matched, then combined and applied to the upper electrode 16, but in the present embodiment, it is shown in FIG. The amplifier 22 used in each of the power supplies 22A and 22B.
It has a configuration in which C is shared. As a result, the number of expensive amplifiers used can be reduced. Moreover, by combining before amplification, processing such as modulation can be performed more easily than by combining after amplification. In the case of performing pulse modulation as the modulation in this case, it is possible to perform film formation processing using plasma by switching on and off and film formation processing using only process gas without generating plasma. Furthermore, by synthesizing before amplification, it is possible to easily switch generation and stop of plasma. That is, it is possible to avoid the need for a switch having a large durability against a connectable / disconnectable current or voltage, which is used for switching between generation and stop of plasma after amplification. Further, it is possible to relatively easily perform monitoring for feedback control regarding power, phase, or frequency for plasma generation before amplification. This is because it is possible to utilize that the gain before amplification is relatively low compared to the case where the above parameters after amplification are used.

On the other hand, the system for loading the semiconductor wafer 12 into the process chamber 10 has the following structure.

That is, a first gate valve 10a is provided on a side portion of the process chamber 10, for example, on the left side, and a load-side load lock chamber (hereinafter, load-side L / L) connected through the gate valve 10a. A chamber) 30 is provided. This loading side L / L
The chamber 30 includes a transfer arm 32 for loading the semiconductor wafer 12 into the process chamber 10 from the sender 40. Here, this transfer arm 32
The first arm 32b has one end rotatably supported on the base 32a, and the second arm 3 has one end rotatably supported on the other end side of the first arm 32b.
2c and a fork 32d fixed to the other end of the second arm 32c are used, but it is also possible to adopt various other transfer means such as the frog leg method. .

Further, the carry-in side L / L chamber 30
A second gate valve 34 is provided on the left side surface of the, and the sender 40 is connected via the gate valve 34. In this sender 40, a cassette 42 for accommodating a plurality of semiconductor wafers 12 arranged in parallel is arranged so as to be vertically movable.

The inside of the carry-in side L / L chamber 30 can be evacuated, and therefore a vacuum exhaust system 70 is provided in this embodiment. That is, one end of the vacuum exhaust pipe 72 is connected to the chamber 30, a valve 74a is provided in the middle thereof, and the other end side is connected to the exhaust pipe 78. In the middle of this exhaust pipe 78,
A mechanical booster pump (MBP) 80 and a rotary pump (RP) 82 are connected. Although not shown, the L / L chamber 30 has a sender 4
A purge gas supply mechanism is provided for switching the internal atmosphere to the atmospheric pressure when the semiconductor wafer 12 is delivered to and from the semiconductor wafer 12.

Further, the unloading system of the semiconductor wafer 12 from the process chamber 10 is constructed as follows.

That is, a third gate valve 10b is provided on the right side of the process chamber 10, and a load lock chamber 50 on the unloading side (hereinafter referred to as L / L chamber on the unloading side) is connected through the gate valve 10b. ing. A transfer arm 52 is arranged in the L / L chamber 50, and a receiver 60 is connected to the right side of the L / L chamber 50 via a fourth gate valve 54. In the receiver 60, a cassette 62 for arranging and supporting the processed semiconductor wafers 12 is arranged. The structure of the carry-out system is similar to the structure of the carry-in system described above, and the vacuum exhaust system 70 of the L / L chamber 50 is used. In addition, this L / L chamber 50
In the same manner as in the L / L chamber 30 of the loading system,
Although not shown, the semiconductor wafer 1 with the receiver 60
There is provided a purge gas supply mechanism for switching the internal pressure to the atmospheric pressure when delivering 2.

On the other hand, in the carry-out side L / L chamber 50,
A structure is provided for removing moisture in the gas accumulated on the surface of the processed semiconductor wafer 12.

That is, an opening 56 is formed in a part of the unloading side L / L chamber 50, especially in a ceiling portion corresponding to a position where it can face the surface of the semiconductor wafer 12, and the opening 56 is formed. A transparent body 58 such as quartz is fitted to form a window. A heating means, for example, a heater 90 is arranged outside the window to heat the inside of the carry-out side L / L chamber 50. A temperature sensor (not shown) is provided on the mounting surface of the semiconductor wafer 12 in the transfer arm 52 so that the surface temperature of the processed semiconductor wafer 12 can be detected.
As the temperature sensor in this case, the direct semiconductor wafer 12
A thermocouple is used that contacts the surface of the. The temperature sensor has an on / off function of outputting a signal for energizing the heater 90 until the surface temperature of the semiconductor wafer 12 reaches room temperature. The temperature sensor may be provided on a pusher pin which is a semiconductor wafer elevating mechanism arranged in the process chamber 10.

Since the present embodiment is constructed as described above,
The semiconductor wafer 12 that has completed the plasma processing is unloaded from the process chamber 10 toward the unloading side L / L chamber 50. That is, the inside of the carry-out side L / L chamber 50 is evacuated to the same vacuum state as the inside of the process chamber 10, and then the third gate valve 10b is opened. Then, the transfer arm 52 enters the process chamber 10 and carries out the semiconductor wafer 12 placed on the lower electrode 14. At this time, the lower electrode 14 is provided with a pusher pin 14A serving as an elevating mechanism for pushing up the semiconductor wafer 12 and inserting the mounting surface of the transfer arm 52 into the lower surface of the semiconductor wafer 12.

The semiconductor wafer 12 carried out from the process chamber 10 is taken into the carry-out side L / L chamber 50. At this time, the third gate valve 10b is closed and the airtightness inside the process chamber 10 is maintained.

On the other hand, the surface temperature of the semiconductor wafer 12 located in the transfer side L / L chamber 50 is detected by a temperature sensor provided on the mounting surface of the transfer arm 52. When the surface temperature of the semiconductor wafer 12 is not room temperature, the heater 90 is energized to heat the semiconductor wafer 12 until it reaches room temperature. Therefore, the semiconductor wafer 1
The process gas remaining on the surface of No. 2 is prevented from being liquefied by being evaporated. Then, when the inside of the carry-out side L / L chamber 50 is switched to the atmospheric pressure, the semiconductor wafer 12 on which such a heat treatment has been carried out is carried out toward the receiver 60 by opening the fourth gate valve 54.

According to the present embodiment, since the semiconductor wafer 12 is carried out after being carried into the load lock chamber 50, in the process chamber 10, regardless of the heating time for the semiconductor wafer 12 after processing. Since the next process for the semiconductor wafer 12 can be executed, it is possible to prevent the process from being delayed in the process chamber.

By the way, the heater 90 which is the above-mentioned heating means
Is not limited to being installed in the load lock chamber 50. That is, it may be provided in the process chamber 10 as shown in FIG. 4, and further, as shown in FIG.
It may be provided in both of the chambers 50. When provided in the process chamber 10, it is preferable to install a reflection shade 92 beside the upper electrode 16 so that the semiconductor wafer 12 can be radiated.

Further, as a method of heating the semiconductor wafer 12, not only the heater 90 is provided in each chamber as described above, but it is also possible to provide it in the transfer means of the semiconductor wafer 12. That is, as the transfer means of the semiconductor wafer 12, there is the transfer arm 52 arranged in the unloading side L / L chamber 50. Therefore, the transfer arm 52
A heater may be installed on the semiconductor wafer mounting surface. In this case, it goes without saying that a thermal cutoff structure for the temperature sensor is provided. With such a configuration, since heating can be performed within the transfer time, the time required for removing water can be included in the carry-out time. Therefore, the throughput for removing water is improved.

Next, another embodiment of the depressurization processing apparatus according to the present invention will be described.

FIG. 6 shows an example in which a purge gas supply structure connected to the carry-out side L / L chamber 50 is used as a heating mechanism for the semiconductor wafer 12. In other words, L of the carry-out system
A heater 90 for heating the purge gas passing through the supply pipe 100 is provided in the middle of the purge gas supply pipe 100 connected to the / L chamber 50. In this case, the heater 90 controls the energization by the pusher pin 1 installed in the process chamber 10.
The temperature sensor provided in 4A is used. This is to set the amount of heat on the heater 90 side required to heat the semiconductor wafer 12 transferred to the transfer side L / L chamber 50 by the transfer arm 52, in other words, the heating temperature.

By the way, in this embodiment, in the loading side L / L chamber 30, the heating of the semiconductor wafer 12 loaded from under the atmospheric pressure atmosphere and the temperature setting at the time of processing in the process chamber 10 can be performed. Has become. That is, in FIG. 7, the loading L / L chamber 30 is provided with a heating station 110 and a cooling station 112. In the heating station 110, heating for evaporating the water vapor adsorbed on the semiconductor wafer 12 is performed. Is performed. Therefore, as shown in FIG. 8, the heating station 110 includes a heating pot 110A capable of forming a closed space, and the transfer arm 3 is provided.
The semiconductor wafer 12 carried in by 2 is heated in the heating pot 1
It can be transferred into 10A. The transferred semiconductor wafer 12 is mounted on a lid-shaped mounting table mounted on the heating pot 110A.
It is carried in and heated. And the heating pot 110
A is the exhaust pipe 11 as in the loading side L / L chamber 30.
The inside can be evacuated via 0B,
The evaporated water is prevented from diffusing into the carry-in side L / L chamber 30. The lid-shaped mounting table is provided to be movable up and down by, for example, a cylinder. In this case, the lifting mechanism is arranged outside the L / L chamber 30 in order to prevent dust generation, and serves as a drive source. The bellows-like airtight member arranged between the bottom surface of the L / L chamber 30 and the L / L chamber 30 blocks the outside air.

On the other hand, near the heating pot 110A, there is provided a cooling station 112 which is insulated from the heating pot 110A.
The susceptor 12 is provided with, for example, a cooling mechanism that can cool the mounted semiconductor wafer 12 while contacting it.

In such a structure, the semiconductor wafer 12 loaded from the sender 40 into the loading L / L chamber 30 is transferred into the heating pot 110A and heated. As a result, the water in the gas that has accumulated on the surface of the semiconductor wafer 12 in the atmosphere is evaporated. After the heating is completed, the semiconductor wafer 12 is taken out of the heating pot 110A and transferred to the cooling station 112.
In the cooling station 112, the process chamber 10
It is cooled to or close to the temperature at which it is cooled. In such a configuration, the heating station 110
If the cooling station 112 is configured as a buffer, the semiconductor wafer 12 carried into the process chamber 10 can be preliminarily prepared, and the start-up time before the process in the process chamber 10 can be shortened. . Moreover, the semiconductor wafer 12 to be preliminarily processed
Since the heating pot 110A eliminates the water content in the gas staying on the surface, dew condensation during cooling can be prevented.

As a structure using such a buffer, as shown in FIG. 9, an L / L chamber 120 for transportation is installed at the center, and the L / L chamber 120 is sandwiched between the processes on both sides. The chamber 10 may be installed, and in this case as well, a buffer capable of heating and cooling can be provided in the L / L chamber 120 as indicated by reference numerals 110A and 112.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention. The vacuum processing apparatus to which the present invention is applied is not limited to the etching apparatus as in the above embodiment, but may be an asher apparatus, a film forming apparatus such as CVD, and the object to be processed is not limited to a semiconductor wafer, Other than the LCD substrate or the like, any material that needs to be processed under a reduced pressure atmosphere may be used.

Although the heater is used as the heating means, the present invention is not limited to this, and it goes without saying that a lamp may be used.

[0046]

As described above, according to the present invention, an object to be processed which has been subjected to an etching treatment in a low temperature state under a reduced pressure atmosphere retains moisture in the gas remaining on the surface before returning to the atmospheric pressure atmosphere. To be removed. Therefore, dew condensation is prevented when returning to the atmospheric pressure atmosphere. Therefore, it is possible to prevent a situation in which the surface condition of the object to be processed is changed when the gas is liquefied and dew condensation occurs, such as when the gas is corrosive.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main structure of an etching apparatus which is an example of a decompression processing apparatus according to the present invention.

FIG. 2 is a block diagram showing a general structure of a power supply structure in the etching apparatus shown in FIG.

3 is a block diagram showing an example of a power supply structure used in the etching apparatus shown in FIG.

FIG. 4 is a schematic diagram showing a modified example of the main part shown in FIG.

FIG. 5 is a schematic diagram showing a further modified example of the main part shown in FIG.

FIG. 6 is a schematic diagram showing another modification of the main part shown in FIG.

FIG. 7 is a schematic plan view for explaining the structure of the main body shown in FIG. 1 on the loading side of the object to be processed.

8 is a schematic perspective view for explaining the internal structure of the carry-in side shown in FIG.

9 is a schematic plan view showing another example of the carry-in side shown in FIG. 7. FIG.

[Explanation of symbols]

 10 Process Chamber 12 Semiconductor Wafer as Object to be Processed 30 Load-side Load-lock Chamber 50 Load-side Load-lock Chamber 90 Heater

Claims (6)

[Claims] 1. A depressurization processing apparatus having a structure in which an object to be processed is depressurized while being cooled on a mounting table in the process chamber, and after processing, the object is transferred to a load lock chamber. A means for heating the object to be processed, which has been processed by either or both of the above, and up to near room temperature while detecting the temperature of the object to be processed before returning the object to be treated from a reduced pressure atmosphere to atmospheric pressure. A decompression treatment device characterized by heating. 2. The depressurization process according to claim 1, wherein the heating means for the object to be processed is provided in a transfer means for transferring the object to be processed between the process chamber and the load lock chamber. apparatus. 3. The heating means according to claim 1, wherein the heating means heats a processed object in the process chamber, and the object is pushed up from the mounting table by a push-up member. A decompression treatment device, which heats in a state. 4. The method according to claim 1, further comprising means for detecting the temperature of the processed object, the temperature detecting means being provided in a transfer means provided in the load lock chamber. A decompression processing device comprising a contact type temperature sensor. 5. The decompression processing apparatus according to claim 3, further comprising means for detecting the temperature of the processed object, the temperature detecting means being provided on the push-up member. 6. A depressurization processing apparatus having a structure in which an object to be processed is depressurized while being cooled on a mounting table in a process chamber, and after processing, the purge gas is loaded into the loadlock chamber. A means for supplying the purge gas, and a means for heating the purge gas. When the processed object is carried out to the load lock chamber, the surface temperature of the object is kept close to room temperature. A decompression treatment device, characterized in that the purge gas is supplied in a heated state.