JP2004087584A - Dry etching device and its dry etching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress dust generation due to pressure variation in a chamber in an etching room and to remove the dust generated by deposition (reaction product). <P>SOLUTION: In a dry etching device having a stage 3 for setting a substance 2 in the etching room 1 and capable of leading temperature transmission gas (He) for cooling the substance 2 into a gap between a rear face and the stage 3 after starting the processing of the substance 2 and exhausting the gas through a temperature transmission gas exhaust line 12 after the end of processing, the gas exhaust line 12 is connected to an exhaust line 15 or 19 different from a processing room exhaust pump 7 to suppress dust generation due to pressure variation which may be generated when the temperature exhaust gas is exhausted. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dry etching apparatus and a dry etching method thereof, and more particularly to a dry etching apparatus and a dry etching method thereof that suppress generation of dust due to pressure fluctuation in a chamber.
[0002]
[Prior art]
In a conventional dry etching apparatus, helium (hereinafter, referred to as He) flows on the back side of a wafer for temperature control as a temperature transmission medium for cooling the wafer. For example, in the case of Japanese Patent Application Laid-Open No. H11-330215, heat is transferred between the substrate and the stage in a vacuum processing chamber as the surface of the substrate (wafer) held on the stage of the substrate holding table is processed. When supplying the gas (He) and controlling the temperature of the substrate, a configuration is shown in which a large flow rate is supplied to the supply and exhaust of the heat transfer gas using a bypass line.
[0003]
The configuration of this conventional example is shown in the sectional view of FIG. In FIG. 3, a stage 3 on which a wafer 2 as an object to be processed is installed is present inside a processing chamber 1a, and a He supply line 13 for cooling the wafer 2 is connected thereto. The processing chamber 1a is evacuated by the processing chamber exhaust pump 7 and further evacuated to a high vacuum by the processing chamber high vacuum pump 6. The processing chamber 1a is connected to a load lock chamber 17 for loading the wafer 2 via a transfer chamber 4 for transporting the wafer 2. The transfer chamber 4 is evacuated from the transfer chamber exhaust line 15a having the valve 11 by the transfer chamber exhaust pump 5, and the load lock chamber 17 is exhausted from the load lock chamber exhaust line 19 having the valve 16 by the load lock chamber exhaust pump 18. You.
[0004]
During the processing, He gas as a heat transfer gas is supplied between the wafer 2 and the stage 3 from a He gas supply source through a He supply line 13a passing through a mass flow controller (hereinafter referred to as MFC) 14, a valve 9, and a valve 8, He is maintained at a high pressure of about 10 Torr. At this time, the He supply line 12a branched from the He supply line 13a is connected to the processing chamber 1a via the valve 10.
[0005]
During the use of the processing chamber 1a, a high pressure state is set to improve the temperature transmission, but after the processing is completed, the wafer 2 is prevented from bouncing due to a pressure difference between the front surface and the back surface of the wafer 2. It is necessary to make the pressure on the back side almost the same as that on the front side. For this reason, the He exhaust lines 12a and 13a are connected to a part of the etching chamber 1a so as to perform a process that naturally has the same pressure.
[0006]
[Problems to be solved by the invention]
As described above, in the conventional etching processing chamber 1a, during the processing in the processing chamber 1a, a high pressure state is used to improve the temperature transmission, but after the processing is completed, the wafer rebound due to the pressure difference between the front and back surfaces of the wafer is reduced. In order to prevent this, it is necessary to make the pressure on the back surface of the wafer 2 substantially equal to the pressure on the front surface. At this time, the timing chart shown in FIG. That is, the pressure in the etching chamber 1a is evacuated by the exhaust pumps 7 and 6 until a high vacuum is reached. 1) When the preparation is completed, 2) He is introduced and the processing is started. 3) When the process is completed, He is exhausted. When this He is exhausted, the pressure in the processing chamber 1a fluctuates as shown in FIG. That is, since the pressure difference between the etching chamber 1a and the back surface of the wafer 2 is large, reaction products (hereinafter referred to as “depots”) in the chamber of the processing chamber 1a deposited during the evacuation process are raised, and Will be detected as dust.
[0007]
That is, the exhaust line 12a for the wafer cooling He is connected to the upper part of the processing chamber exhaust pump 6, and a large pressure is applied between the processing chamber 1a in a high vacuum state of 1 mTorr and the 10 Torr He exhaust line during He exhaust. There is a difference, and the upper part of the processing chamber exhaust pump 6 flies up the surrounding depot due to rapid pressure fluctuation, and the depot flows into the processing chamber 1a connected horizontally as dust.
[0008]
An object of the present invention is to provide a dry etching apparatus and a dry etching method for suppressing dust generation due to pressure fluctuation in the chamber of the etching processing chamber and eliminating dust by a deposit.
[0009]
[Means for Solving the Problems]
The configuration of the present invention has a stage for placing an object to be processed inside an etching chamber, and the temperature transfer gas for cooling the object to be processed is disposed between the back surface and the stage after the processing of the object is started. In the dry etching apparatus which is introduced and is exhausted by the temperature transmission gas exhaust line after the processing is completed, the temperature transmission gas is connected by connecting the gas exhaust line to any one of exhaust lines separate from the processing chamber exhaust pump. Dust generation due to pressure fluctuation during gas exhaust is suppressed.
[0010]
In the present invention, another exhaust system line may be a transfer chamber exhaust line of a transfer chamber adjacent to the etching processing chamber, and may be a load lock chamber exhaust line that is a front chamber of the transfer chamber. The workpiece may be a wafer and the temperature transfer gas may be helium.
[0011]
The structure of the present invention has a stage for placing an object to be processed inside an etching chamber, and the temperature transfer gas for cooling the object is supplied between the back surface and the stage after the processing of the object is started. In the dry etching method, which is introduced from a supply line and is exhausted by an exhaust line of the temperature transfer gas after the processing is completed, when the processing of the processing object is completed, the pressure difference between the processing chamber and the back surface of the processing object is reduced. According to the configuration of the present invention, the gas exhaust line is connected to any one of exhaust lines separate from the processing chamber exhaust pump so as to eliminate the pressure, and the gas is exhausted through the exhaust line. Helium gas, which is used as a gas, is introduced between the back surface of the wafer and the stage after the processing of one wafer is started, and after the processing of one wafer, the He gas exhaust line is used. Issued, by connecting the gas exhaust line to another one of the exhaust system line from the processing chamber exhaust pump, it is possible to prevent the winding up of the refuse processing chamber vent at a He gas exhaust.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a dry etching apparatus for explaining an embodiment of the present invention. In this embodiment, similarly to the conventional example, the processing chamber 1 is connected to the processing chamber exhaust pump 7 and the processing chamber high vacuum pump 6, and the transfer chamber 4 is connected to the transfer chamber exhaust pump 5 through the transfer chamber exhaust line 15 having the valve 11. The load lock chamber 17 is connected to a load lock chamber exhaust pump 18 via a load lock chamber exhaust line 19 having a valve 16.
[0013]
The present embodiment is characterized in that the exhaust line 12 for the wafer cooling He is connected to the transfer chamber exhaust line 15. In addition, by connecting the exhaust line 12 to the transfer chamber exhaust pump 5 side of the valve 11 between the transfer chamber 4 and the transfer chamber exhaust pump 5, the operation of the valve 11 is not required during He exhaust.
[0014]
As in the conventional etching apparatus, there is a stage 3 in which the wafer 2 is set in the processing chamber 1, and a He supply line 13 for cooling the wafer 2 is connected to the stage 3. During the processing of the wafer 2, He supplied from the He gas supply source through the MFC 14, the valve 9, and the valve 8 is maintained at a high pressure of about 10 Torr between the wafer 2 and the stage 3. After the processing is completed, the valve 9 is closed, and the air is exhausted by the transfer chamber exhaust pump 5 through the valves 8 and 10.
[0015]
Next, the operation of the present embodiment will be described. First, the wafer 2 is transferred from the transfer chamber 4 onto the stage 3 in the processing chamber 1, and preparation for starting the etching process is completed. At this stage, both the valve 8 and the valve 10 are closed, and there is no supply and exhaust of He. Next, when the processing of the wafer 2 is started, the valve 8, the valve 9, and the MFC 14 are opened, and He is supplied between the wafer 2 and the stage 3. The valve 10 is closed and the He supply line 13 is maintained at a pressure of about 10 Torr. At this time, the inside of the processing chamber 1 is maintained at 1 to 100 mTorr in accordance with the processing conditions.
[0016]
When the processing of the wafer 2 is completed, the pressure on the back surface of the wafer 2 from the He supply line 13 is set to prevent the wafer 2 from jumping due to the differential pressure of the He pressure on the back surface of the wafer 2 from the processing chamber 1 and the He supply line 13. Is exhausted by the transfer chamber exhaust pump 5 through the valve 8, the valve 10, and the He exhaust line 12. Thus, the processing chamber 1 is not affected by the pressure fluctuation at the time of He exhaust, unlike the pressure timing chart of FIG.
[0017]
In this case, even if the pressure in the transfer chamber 4 increases due to the influence of the increase in the pressure of the He exhaust line 12, there is no deposit of the reaction product due to the processing inside the transfer chamber 4, so that dust is generated. Unlikely.
[0018]
According to the present embodiment, by connecting the exhaust line 12 for He for cooling the wafer to the exhaust line 15 for the transfer chamber, it is possible to prevent dust from being generated in the processing chamber 1 due to an increase in pressure above the high vacuum pump in the processing chamber. On the other hand, even if there is a pressure difference between the transfer chamber 4 and the He exhaust line 12 during He exhaust, there is no depot serving as a source of dust in the transfer chamber exhaust line 15, so that the transfer chamber 4 There is no dust, and no dust adheres to the wafer 2 during wafer transfer.
[0019]
In the present embodiment, the connection of the He exhaust line 12 is made to the transfer chamber exhaust line 15, but the connection of the He exhaust line 12 is changed to the load lock exhaust line 19 instead of the transfer chamber exhaust line 15. The effect of is obtained. In addition, in the case of an apparatus having an exhaust line other than the processing chamber 1, a He exhaust line 12 can be connected to the exhaust line.
[0020]
【The invention's effect】
According to the configuration of the present invention described above, by connecting the He exhaust line from the connection of the processing chamber exhaust pump to the transfer chamber exhaust pump, it is possible to prevent dust from rising inside the processing chamber and prevent dust from being deposited on the wafer. There is an effect that can be done.
[0021]
Further, in the present invention, the exhaust line of the wafer cooling He is connected to the transfer chamber exhaust line, thereby preventing generation of dust in the process chamber due to a pressure increase of the process chamber high vacuum pump. Even if there is a pressure difference between the He exhaust line and the He exhaust line, there is no debris that originates in the transfer chamber exhaust line, so there is no dust in the transfer chamber, and dust adheres to the wafer during wafer transfer. Does not occur.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a dry etching apparatus schematically illustrating one embodiment of the present invention.
FIG. 2 is a timing chart of pressure in a control chamber and an exhaust line for explaining the operation of FIG. 1;
FIG. 3 is a cross-sectional view of a dry etching apparatus schematically illustrating a conventional example.
FIG. 4 is a timing chart of pressure in a control chamber and an exhaust line for explaining the operation of FIG. 3;
[Explanation of symbols]
1, 1a (vacuum) processing chamber 2 wafer 3 stage 4 transfer chamber 5 transfer chamber exhaust pump 6 processing chamber high vacuum pump 7 processing chamber exhaust pump 8-11, 16 Valve 12, 12a, 13, 13a He exhaust line 14 MFC ( Mass flow controller)
15, 15a Transfer chamber chamber exhaust line 17 Load lock chamber 18 Load lock chamber exhaust pump 19 Load lock chamber exhaust line

Claims (7)

A stage for placing the object in the etching chamber; a temperature transmitting gas for cooling the object is introduced between the back surface and the stage after the start of the processing of the object; In a dry etching apparatus which is later discharged by the temperature transmission gas exhaust line, the pressure fluctuation at the time of exhausting the temperature transmission gas is achieved by connecting the gas exhaust line to any exhaust system line different from the processing chamber exhaust pump. A dry etching apparatus characterized in that dust generation due to air is suppressed. 2. The dry etching apparatus according to claim 1, wherein the other exhaust system line is a transfer chamber exhaust line of a transfer chamber adjacent to the etching processing chamber. 2. The dry etching apparatus according to claim 1, wherein the other exhaust system line is an exhaust line of a load lock chamber which is a front chamber of the transfer chamber. 4. The dry etching apparatus according to claim 1, wherein the object to be processed is a wafer, and the temperature transfer gas is helium. A stage for setting the object to be processed in the interior of the etching chamber, a temperature transfer gas for cooling the object to be processed is introduced from a gas supply line between the back surface and the stage after the start of the processing of the object to be processed, In the dry etching method in which the temperature transmission gas is exhausted by an exhaust line after the processing, when the processing of the processing object is completed, the pressure difference between the processing chamber and the back surface of the processing object is eliminated. A dry etching method, wherein the gas exhaust line is connected to any exhaust system line different from the processing chamber exhaust pump, and exhaust is performed through the exhaust line. A dry etching method comprising: a stage for setting an object to be processed inside an etching chamber; and a temperature transfer gas for cooling the object to be processed is introduced from a gas supply line and exhausted by a gas exhaust line of the temperature transfer gas. When the object to be processed is conveyed onto a stage in the processing chamber and preparation for processing is completed, there is no supply or exhaust of the temperature transfer gas; when the processing of the object is started, The temperature transfer gas is supplied from a gas supply line between the workpiece and the stage, and a gas exhaust line is maintained at a predetermined pressure; when the processing of the workpiece is completed, the processing chamber and the workpiece are In order to eliminate the pressure difference between the pressures on the back surface of the processing object, the pressure on the back surface of the object to be processed is changed from the gas supply line, and the gas exhaust line is connected to any one of exhaust systems other than the processing chamber exhaust pump. The dry etching method, characterized in that connected to the in-exhausting from the exhaust line. 7. The dry etching method according to claim 5, wherein the object to be processed is a wafer, and the temperature transfer gas is helium.

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