JPS6295828A - plasma processing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a plasma processing apparatus.

[Background of the invention]

An example of a plasma processing apparatus having a processing chamber in which a sample is processed using plasma is a dry etching apparatus. FIG. 6 shows a longitudinal section of a typical example of a conventional dry etching apparatus. As shown in FIG. 6, two flat plate electrodes 2.3 are arranged facing each other in a sealed processing chamber 1, a high frequency type #4 is connected to one electrode 3, and the opposite electrode 2. The structure is such that raw material gas can be supplied from the

A vacuum pump 5 is connected to the processing chamber 1.
The gas inside can be sucked and exhausted. The sample to be dry etched, for example, the wafer 6, has the surface coated with the M thin film as the electrode 2.
In the dry etching process, the air in the processing chamber 1 is first exhausted, and then the raw material gas 8+C14, CCI! 4. and BCI! A gas such as No. 3 is supplied to heat the inside of the processing chamber 1 to a predetermined pressure of about 0.01 to 5 Torr.

In that state, applying high frequency power between electrodes 2 and 3,
Active ionic species are generated by glow discharge and reacted with MI'Jm to perform etching. Due to the etching reaction, aluminum chloride (hereinafter referred to as M chloride) is produced in the processing chamber 1.
Since the wafer re-adheres and deposits on the inner surface of the wafer and the electrode 2.3, there is a risk that the etching reaction may become unstable or the deposit may turn into dust and fall onto the wafer.

Normally, it is necessary to periodically open the flange 7 to expose the inside of the processing chamber 1 to the atmosphere to remove deposits.

For this reason, methods for removing deposited adhesion products have been devised for conventional apparatuses as described below.

For example, in Japanese Patent Application Laid-Open No. 59-143073, a heated inert gas is introduced into the process chamber 1 to evaporate M chloride. but.

The second method does not reduce the amount of deposition during etching, and requires interruption of the dry etching apparatus in order to heat with inert gas. Furthermore, as described in Japanese Patent Application Laid-Open No. 59-134832, by making the part of the electrode 3 other than the wafer made of carbon, which has poor thermal conductivity, the part of the electrode other than the part covered with the wafer can be heated to a high temperature. This prevents reaction products from adhering. However, this method is insufficient because no measures are taken for the inner surface of the processing chamber 1. In addition, some known dry etching devices place a cooled ring around the electrode corresponding to electrode 3, and the reaction product adheres to the ring, but this method cannot be said to be sufficient. do not have. Although a cooled rod-shaped member is placed in place of the ring described above, the reality is that a sufficient effect cannot be expected.

As described above, in the prior art, there is no effective method or device for preventing or removing reaction products from accumulating during operation. It is carried out. Therefore, the inside of the processing chamber 1 and the electrode 2. The electric wire w13 is exposed to the atmospheric environment, which causes corrosion, leading to a decrease in the reliability of the dry etching device (.Furthermore, it is necessary to stop the operation of the dry etching device, reducing production capacity.

[Purpose of the invention]

It is an object of the present invention to improve productivity and reliability by preventing and removing reaction products in a processing chamber without interrupting operation or exposing the interior of the processing chamber to the atmospheric environment. An object of the present invention is to provide a plasma processing apparatus that can improve performance.

[Summary of the invention]

The present invention provides a plasma processing apparatus that uses plasma inside the processing chamber in which a sample is processed, or outside the processing chamber, without affecting the plasma (with an internal isolation chamber between the heating gas and the processing chamber). This device prevents reaction products from accumulating in the processing chamber without interrupting operation or exposing the inside of the processing chamber to the atmospheric environment.
That's what I was trying to remove.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows a longitudinal section of a dry etching apparatus to which the present invention is applied, gas supply and exhaust pipes, and high-frequency
Connections such as i are shown. In FIG. 1, processing chamber 1. Electrode 2
,3. High frequency power supply 4° vacuum pump 5. The wafer 6, flange 7, etc. are the same as in FIG. However, the difference from Figure @6 is that in Figure 1 there are two electrodes inside the processing chamber l. An isolation chamber 8 is provided to surround the processing chamber 1, and a piping system for supplying heated inert gas is connected to the processing chamber 1. The inert gas piping system is pipe line 9. Flow controller 10. Heater 11. It is made up of valve votes. The flow rate and temperature of the inert gas can be adjusted to predetermined conditions by the flow controller IO and heater 11, respectively. When the valve is opened, inert gas at a predetermined temperature and flow rate is supplied to the processing chamber 1 from the inert gas inlet 13, and the pressure within the processing chamber 1 can be adjusted by adjusting the flow rate. The source gas is supplied to valve 1.
4, and the raw material gas passes through the electrode 3 to the isolation chamber 8.
supply within. FIG. 2 shows an enlarged longitudinal section of the isolation chamber 8. As shown in FIG. 2, the isolation chamber 8 consists of a cylindrical partition wall 81 and an upper corner m82. The cylindrical space IJe81 is provided with a stay blade, and the upper corner U&82 is provided with an insertion hole into which the raw material gas 15 is inserted. An upper partition is placed on the upper end surface of a stay wing provided near the upper end of the inner wall of the cylindrical partition 81. The contact area between the upper end surface of this stay blade and the upper partition blade does not need to be airtight.

Forming of ceramics, etc. 1. Keep the gaps as small as possible within the precision of machining, cutting, polishing, etc. The contact surface between the lower end surface of the cylindrical partition wall 81 and the flange 71 of the processing chamber, the upper partition wall catfish, the raw material gas population 15, and the flange 7
The contact surface with 2 is also made as small as possible within the precision range of industrial molding 1 machine cutting, polishing, etc.

In FIG. 1, 16 and 16' are a raw material gas exhaust port and an inert gas exhaust port, respectively. The raw material gas is discharged from exhaust port 1.
6, it is evacuated to the outside of the processing chamber l by a vacuum pump 5. The inert gas is evacuated from the exhaust port 16/ by the vacuum pump 5'.

The isolation chamber 8 shown in FIG. 2 is made of electrically insulating materials such as alumina, quartz, and Teflon that do not cause abnormal discharge when dry etching wafers, and that can be used in a temperature range of 70°C or higher. Use materials that can be used for a long time.

When etching the M thin film on a wafer using the dry etching apparatus equipped with the isolation chamber 8 as described above, the following operations are performed. First, the air in the processing chamber 1 is evacuated by the vacuum pumps 5 and 5'. Evacuation by the vacuum pumps 5 and 5' is continued, the valve 14 is opened to allow the raw material gas to flow, and then the valve L is opened to supply heated inert gas into the processing chamber 1 from the inert gas port 13. Isolation room 8
Since the aM1 pressure of the raw material gas inside must be maintained under constant conditions, the flow rate controller 10 is adjusted so that inert gas does not flow into the isolation chamber 8. In this case, the second
As shown in the figure, the upper corner of isolation room 8 is U! The part where the raw material gas population 15 is inserted into the proverb, the upper partition wall catfish and the cylinder partition ff18
A gap is formed in the contact area between the cylindrical partition wall 81 and the flange n. The resistance to the gas flow of the flow path formed by the space is larger than that of the gas flow. Therefore, the inert gas supplied into the processing chamber 1 flows along the outside of the isolation chamber 8 while heating the isolation chamber 8, flows into the exhaust port 16', and flows into the vacuum pump 5'.
is exhausted to the outside of the processing chamber 1. On the other hand, the raw material gas flows into the isolation chamber 8 from the electrode 2, and a small amount of it mixes with the inert gas through the gap between the cylindrical partition 81 and the upper partition blade, but most of it, as in the prior art, It flows down toward the electrode 3, flows into the exhaust port 16, and is exhausted to the outside of the processing chamber by the vacuum pump 5. The temperature of the inert gas is adjusted to such an extent that the temperature of the isolation chamber 8 is 70° C. or higher under the above conditions.

A glow discharge is generated between the electrodes 2 and 3 by the high frequency power source 4.

When the wafer 6 is etched, M chloride is generated due to the etching reaction, but even when it reaches the isolation wall 8, the temperature of the partition wall has risen by 70°C or more, so the M chloride is mixed into the gas without being condensed. The gas flows into the exhaust port 161 and is exhausted to the outside of the processing chamber by the vacuum pump 5. As described above, it is possible to prevent reaction products from adhering to the inside of the dry etching device.
E I can do it.

Next, FIGS. 3 to 5 show other embodiments of the present invention.

The difference between FIG. 3 and FIG. 1 lies in the structure of the isolation g17 and the use of one vacuum pump accordingly. FIG. 4 shows a longitudinal section of the isolation chamber 17.

As shown in FIG.
.

Top corner W 172 , bottom partition wall 173 . Support stand 174
It consists of A stay 175 is provided on the cylindrical partition wall 171, and an upper corner IJ! 172 (and upper bulkhead 1)
The provision of an insertion hole 176 for the raw material gas inlet 15 at 72 is the same as in the case of FIG. The difference in FIG. 4 from the isolation chamber 8 shown in FIG. 2 is that the bottom partition wall 173. Support stand 17
The reason is that 4 was established. One or more raw material gas ventilation holes 177 are opened in the bottom partition fi 173. The diameter of the raw material gas vent 177 is preferably as small as possible as long as the raw material gas supplied through the WL electrode can be exhausted by the vacuum pump 5. Further, a stop plate 178 serving as a guide is provided on one side of the bottom partition wall 174, into which a support stand 174 is inserted as shown in FIG. A shaft hole 179 into which the shaft weight 8 of the pole 2 is inserted is provided in the center of the bottom partition wall 173. The diameter of the insertion hole 176 may be close to the outer diameter of the raw material gas hole 15 as long as the raw material gas hole 15 can be easily inserted therein. Also,
The diameter of the shaft hole 179 may be as close as possible to the outer diameter of the shaft 18 within a range that allows the shaft 18 to be inserted easily. In addition, an inert gas vent 1710 is provided on the side of the support stand 174.
Open one or more. The diameter of the inert gas vents 1710 should be as large as possible, and the number should be as large as possible.

Dry Elatin equipped with isolation chamber 17 as described above.

The operation of etching the MN film on the wafer using the etching device is almost the same as that shown in Figure 1 above, but since the etching gas is less corrosive, an inert gas vacuum pump is used. When possible, there is an advantage that a single vacuum pump can be operated for the following reasons. In the embodiment shown in FIG. 3 as well, the pressure of the source gas in the isolation chamber 17 is adjusted to a constant value, so the pressure of the inert gas is adjusted to such an extent that the inert gas does not flow into the isolation chamber. As shown in FIG. 3, the portion of the isolation chamber 17 where the raw material gas port 15 is inserted into the upper partition wall 172 and the contact portion between the upper partition wall 172 and the cylindrical partition wall 171 are simply in contact and do not form a gap. However, the resistance for gas to pass through that gap is
7 and the inner surface of the processing chamber 1 and the support stand 174
The resistance of the flow path formed by the inert gas vent 1710 is greater than the resistance of the flow path formed by the inert gas vent 1710.

Therefore, the gas supplied into the processing chamber 1 is
The gas is evacuated from the exhaust port 16 at the bottom of the processing chamber 1 by a vacuum pump through a passage formed between the outside of the processing chamber 1 and the processing chamber 1 . The raw material gas flows into the isolation chamber 17 from the electrode 2, passes through the gap formed in the upper part of the isolation chamber 17, and a small amount of it mixes with the inert gas, but as in the prior art, most of it flows toward the electrode 3. Flow, raw material gas vent 1 at the bottom of isolation chamber 17
It flows into the exhaust port I6 through 77 and is exhausted out of the processing chamber 1 by the pump 5. Adjust the temperature of the inert gas to isolation chamber 1.
The temperature of the pot should be adjusted to 70° C. or higher, as in the embodiment shown in FIG. 1 and FIG. 752.

It is possible to prevent reaction products from being deposited inside the dry etching device.

In the above embodiments, the isolation chamber is provided within the processing chamber, but the isolation chamber may be provided in the opposite manner. In addition, as the plasma processing apparatus, there is no particular problem in application of an apparatus in which reaction products can be deposited by adhering to the wall surface of the processing chamber, such as a plasma CVD 51 and a plasma processing apparatus.

〔Effect of the invention〕

As explained above, the present invention can prevent and remove reaction products from accumulating in the processing chamber without interrupting operation or exposing the inside of the processing chamber to the atmospheric environment. This has the effect of improving the productivity and reliability of processing equipment.

[Brief explanation of drawings]

The first factor is a block diagram of a dry etching apparatus showing an embodiment of the plasma processing apparatus according to the present invention, FIG. 2 is a longitudinal sectional view of the isolation chamber of FIG. 1, and FIG. A block diagram of a dry etching apparatus showing another embodiment of the apparatus, FIG. 4 is a vertical sectional view of the isolation chamber of FIG. 3, FIG. 5 is a plan view similarly seen from the bottom, and the sixth factor is dry etching FIG. 1 is a configuration diagram showing a conventional example of an apparatus. 1... Processing chamber, 2, 3... Electrode, 4.
...High frequency electric source, 5,5'...Vacuum pump, 8,17...Separate chamber, 9...Pipe line, 10... ...Landscape controller, 11...
...heater 111 figure, Niji H Pong figure 3 figure 4 figure 5 figure

Claims (1)

[Claims] 1. A plasma characterized in that an isolation chamber is provided inside or outside the processing chamber in which a sample is processed using plasma, and in which heated gas is inserted between the processing chamber and the processing chamber without affecting the plasma. Processing equipment.