JPH08162412A - Semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE: To improve device characteristics and production yield, by preventing reaction product in plasma from attaching on a side wall, and eliminating the generation cause of particles. CONSTITUTION: In a semiconductor manufacturing equipment wherein plasma for reaction gas formation is used in a reaction chamber 12, and film formation or etching is performed for a semiconductor wafer 18, a plasma generator 11 is installed outside the reaction chamber 12. The plasma generator 11 generates plasma which is different from the plasma for gas pumping and used for preventing reaction product from attaching on the side wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to a plasma processing apparatus for forming a film on a semiconductor substrate or etching it by using plasma.

[0002]

2. Description of the Related Art As semiconductor devices have become highly integrated and miniaturized, particles adhering to a semiconductor substrate during manufacturing have a great influence on device characteristics and production yield. As the particle generation source, in addition to dust generated from the transportation system of the semiconductor manufacturing apparatus, dust generated from people, etc.,
The products in the process step are listed. The reaction product (processing chamber) is the reaction product of particles with low vapor pressure.
It is caused by the fact that it adheres to and is peeled off. Therefore, in a plasma processing apparatus such as a dry etching apparatus or a CVD apparatus, measures against this particle are required.

Reaction products adhering to the inner wall of the reaction chamber are removed by wet cleaning with chemicals or dry cleaning with plasma. Also,
In the prior arts such as JP-A-62-130524, JP-A-3-55832, and JP-A-5-62936, an electrode different from the electrode for generating plasma for gas excitation is installed near the side wall, and There are many references to plasma cleaning the deposited product.

FIG. 6 shows a block diagram of a plasma processing apparatus as disclosed in Japanese Patent Laid-Open No. 62-130524. As shown in FIG. 6, the plasma processing apparatus having a cleaning function as seen here has a counter electrode 2 and a susceptor-cum-electrode 3 that generate plasma for gas excitation, as shown in FIG.
And a protective plate 4 for protecting the side wall of the reaction chamber from the plasma.
And a cleaning electrode 5 for generating plasma for cleaning. The cleaning electrode 5 is provided inside the reaction chamber 1 and on the back surface of the protective plate 4. Further, outside the reaction chamber 1, there is provided a switch 6 for switching between plasma processing and cleaning operation, and a high frequency power source 7 for supplying high frequency power to the electrode 3 also serving as the susceptor or the cleaning electrode 5.

Next, the operation of the plasma processing apparatus will be described. When dry cleaning the reaction product attached to the protective plate 4, first, the switch 6 is switched to connect the high-frequency power source 7 to the cleaning electrode 5 and connect the susceptor / electrode 3 to the ground line. Next, the cleaning gas 8 is introduced into the reaction chamber 7. As a result, the cleaning electrode 5
Plasma for cleaning is generated between the electrode and the electrode 3 also serving as the susceptor, and the reaction product attached to the protective plate 4 is separated by the cleaning gas 8 and one reaction product is discharged from the reaction chamber 7 to the outside.

Further, when the semiconductor substrate 18 is formed into a film or etched, the switch 6 is switched to connect the high frequency power source 7 to the electrode 3 serving also as the susceptor and introduce the vapor phase growth gas into the reaction chamber 7. As a result, the first plasma is generated between the electrode 3 serving also as the susceptor and the counter electrode 2, and the semiconductor substrate 18 is formed into a film by the vapor growth gas or the reaction gas is changed to etch the substrate 20. be able to. At this time, the side wall of the reaction chamber is protected by the protective plate 4 from the first plasma.

[0007]

However, according to the conventional cleaning method, the reaction products attached to the protective plate 4 are separately removed by using a cleaning gas different from the reaction gas for vapor phase growth. Therefore, if the cleaning time of the protective plate 4 is delayed or the cleaning cycle is lengthened, a large amount of particles are generated. Further, if the cleaning cycle is shortened, the throughput of the plasma processing apparatus is significantly reduced, which causes a decrease in the productivity of the entire manufacturing plant.

A method of raising the temperature of the side wall may be considered in order to reduce the amount of the reaction product adhering to the side wall, but at a temperature in the practical range, the effect of reducing the side wall is small, and it is effective as a measure for reducing particles. The current situation is that there are none.
As a result, there is a problem that the influence of particles on the semiconductor substrate becomes more and more serious as devices are highly integrated and miniaturized, which hinders improvement of device characteristics and production yield.

The present invention was created in view of the problems of the conventional example, and prevents the reaction products in the plasma from adhering to the sidewalls, eliminating the cause of particle generation, device characteristics and production. An object of the present invention is to provide a semiconductor manufacturing apparatus capable of improving the yield.

[0010]

A semiconductor manufacturing apparatus according to the present invention has a reaction chamber 12 as shown in FIGS.
In the semiconductor manufacturing apparatus for forming a film on a semiconductor substrate or etching using a first plasma, a plasma generator 11 for generating a second plasma different from the first plasma is used for the reaction. It is provided outside the chamber 12.

The semiconductor manufacturing apparatus of the present invention is preferably characterized in that the plasma generator 11 has a plurality of electromagnetic coils 11A arranged around the outside of the reaction chamber 12. In the semiconductor manufacturing apparatus of the present invention, the exciting current supplied to one electromagnetic coil 11A is preferably another electromagnetic coil 11 arranged adjacent to the electromagnetic coil 11A.
The phase is shifted by 180 ° with respect to the exciting current of B.

In the semiconductor manufacturing apparatus of the present invention, at least the second plasma is generated while the first plasma is being generated, and the above object is achieved.

[0013]

[Operation] According to the semiconductor manufacturing apparatus of the present invention, the reaction chamber 1
Since the plasma generator 11 is provided outside the first
Another second plasma different from that of the reaction chamber 12
Can be generated in the vicinity of the inner wall of the reaction chamber, and the reaction products can be prevented from adhering to the side wall of the reaction chamber 12.

As a result, the reaction product is dissociated by the second plasma. As a result, the reaction product does not adhere to the vicinity of the inner wall of the reaction chamber 12, the cause of particle generation is removed, and the device characteristics and the production yield are improved. It is possible to improve. The second plasma is supplied to the plurality of electromagnetic coils 11A of the plasma generator 11 arranged around the outside of the reaction chamber 12 by supplying an exciting current with a phase difference of 180 ° between the adjacent electromagnetic coils 11A and 11B. Then, a magnetic field that fluctuates with time is generated, and the electric field fluctuates with time according to Faraday's law of electromagnetic induction.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 5 are explanatory views of a semiconductor manufacturing apparatus according to each embodiment of the present invention. (1) Description of First Embodiment FIG. 1 is a cross-sectional view illustrating the configuration of a dry etching apparatus according to the first embodiment of the present invention, and FIG. 2 is a plan view illustrating the arrangement of electromagnetic coils. FIG. 3 is a functional explanatory diagram of the plasma generator.

As shown in FIG. 1, a parallel plate type high frequency application type reactive ion etching apparatus, which is an example of a dry etching apparatus, has a plasma generator 11, a reaction chamber 12, a cathode electrode 13, a heater / electrode 14 and a high frequency power source 17. Is equipped with. The plasma generator 11 has an electromagnetic coil 11A and a high-frequency power source 11C, and another plasma for preventing adhesion (second plasma) different from the gas excitation plasma (first plasma) is supplied to the reaction chamber 12. It occurs near the inner wall. The plasma generator 11 is provided outside the reaction chamber 12 and has 16 electromagnetic coils 11A. The electromagnetic coil 11A is arranged around the outside of the reaction chamber 12. It may be preferably provided above and below the outside of the reaction chamber 12.

The high frequency power source 11C supplies a frequency to the electromagnetic coil 11A.
It supplies a high-frequency signal of 13.56 MHz. Power supply 11
C is provided separately from the high frequency power supply 17 for generating plasma for gas excitation. The high frequency power supply 11C may be synchronized with the high frequency power supply 17 to adjust the output. Thereby, the plasma for adhesion prevention can be generated while the plasma for gas excitation is being generated.

When the two power sources are used as a common power source, a power source whose output can be adjusted individually is applied. The exciting current supplied to one electromagnetic coil 11A is 180 ° out of phase with the exciting current of the adjacent electromagnetic coil 11B. As a result, the 16 electromagnetic coils 11A alternately generate the magnetic field of the N pole and the magnetic field of the S pole alternately, as shown in the plan view of FIG.

The reaction chamber 12 has a cylindrical shape made of stainless steel (SUS), and has a cathode electrode 13 and a heater / electrode 14 therein. The cathode electrode 13 is grounded and also serves as a shower plate that blows out the reaction gas 15. For example, when dry etching the semiconductor wafer 18 having a two-layer structure of WSi and Poly-Si, a mixed gas of HBr and Cl ₂ is used as the reaction gas 15.

The heater / electrode 14 is connected to a high frequency power source 17 and also serves as a heater for heating the semiconductor wafer 18. The high frequency power supply 17 supplies a high frequency signal having a frequency of 13.56 MHz to the electrode 14. Next, the etching operation of the apparatus will be described with reference to FIGS. First, in FIG. 1, the reaction chamber 12 is evacuated to a vacuum degree of 0.1 Torr.
The semiconductor wafer 18 is placed on the electrode 14 by vacuuming to some extent. Next, plasma for gas excitation and plasma for preventing adhesion are generated in the reaction chamber 12. The former is a frequency of 13.56 MHz from the high frequency power supply 17 between the electrodes 13 and 14.
2 is generated when the high frequency signal of
16 electromagnetic coils 11A as shown in
It is generated when a high frequency signal of similar frequency is supplied from C.

At this time, depending on the size of the reaction chamber 12, the separation distance between the plasma for gas excitation and the inner wall is 5 cm.
In some cases, plasma for adhesion prevention is generated within 2 cm near the inner wall. FIG. 3 shows an explanatory diagram of the principle of generation of plasma for preventing adhesion. In FIG. 3 (A), the electromagnetic coil 11A receives a high frequency signal with a frequency of 13.56 MHz,
A magnetic field whose strength changes with time is generated, and an electric field that fluctuates with time is generated according to Faraday's law of electromagnetic induction as shown in FIG. Due to this change in the electric field, plasma for adhesion prevention is generated near the inner wall of the reaction chamber 12. When the mixed gas 17 of HBr and Cl ₂ is introduced into the reaction chamber 12 while always maintaining this state, the semiconductor wafer 18
Are dry-etched.

FIG. 4 is a diagram for explaining the function of the protective plasma, and FIG. 4 (A) shows a state diagram in which the plasma is off. In FIG. 4A, when the plasma for preventing adhesion is turned off, the atoms and molecules in the plasma flow down, and the atoms and molecules are recombined when returning to a more stable state. At this time, in the case of a molecule having a high vapor pressure, the exhaust gas 16 is kept outside the reaction chamber 12 as it is.
However, in the case of molecules having a low vapor pressure, the reaction product 21 remains in the reaction chamber 12. This reaction product 21 has a low energy particularly near the inner wall, so that recombination frequently occurs and it is attached to the wall.

On the other hand, as shown in FIG.
When the plasma for adhesion prevention is generated in the vicinity of the inner wall, the movement of electrons in the plasma becomes intense, the dissociation reaction of the recombined reaction product 21 increases, and the generation of the product having a low vapor pressure is prevented. At the same time, the adhesion of the reaction product 21 to the inner wall is extremely reduced. In this way, according to the dry etching apparatus of the first embodiment of the present invention, as shown in FIG. 1, since the plasma generator 11 is provided outside the reaction chamber 12, the plasma for gas excitation is provided. A plasma for adhesion prevention different from that can be generated with good controllability in the vicinity of the inner wall of the reaction chamber, and dissociation of the reaction product 21 as shown in FIG. 4B can be promoted. Adhesion of the reaction product 21 to the side wall of 12 is prevented.

As a result, even if the reaction product having a low vapor pressure downflowing from the plasma for gas excitation is recombined in an attempt to return to a stable state, the reaction product is dissociated by the plasma for adhesion prevention. , Reaction chamber 1 in the conventional example
A large amount of SiBrO-based products and the like adhered to the inner wall of 2, but the reaction product 21 hardly adhered due to the plasma for preventing the adhesion.

The reaction product adhesion preventing function of this embodiment is extremely difficult with the cleaning method of the conventional example. This is because it is difficult to introduce the cleaning gas only in the vicinity of the side wall during the plasma treatment and to clean with the plasma first reaction gas.
As a result, the cause of generation of particles can be removed, and the number of times of cleaning the reaction chamber 12 can be reduced. Further, the maintenance work is eased, and the maintenance cycle can be lengthened. By improving the reliability of the dry etching apparatus and the throughput of the apparatus, the device characteristics and the production yield can be improved.

(2) Description of Second Embodiment FIG. 5 shows a parallel plate type WC according to a second embodiment of the present invention.
The block diagram of a VD apparatus is shown. In the second embodiment, the first
Unlike the above embodiment, the plasma generator 11 for generating plasma for adhesion prevention is applied to the film forming apparatus. As shown in FIG. 5, the parallel plate type W-CVD apparatus includes a plasma generator 11, a reaction chamber 22, a shower plate / electrode 23, a heater / electrode 24, and a high-frequency power source 27. Unlike the first embodiment, the high frequency power supply 27 is connected to the electrode 23 and the electrode 24 is grounded. A reaction gas 27 is introduced into the shower plate / electrode 23. For example, when vapor-depositing a W (tungsten) film on the semiconductor wafer 18, a mixed gas of WF ₆ and H ₂ is used as the reaction gas 27. Other configurations and those having the same names as those in the first embodiment have the same functions, and therefore their explanations are omitted.

Next, the film forming operation of the apparatus will be described. First, in FIG. 5, the reaction chamber 22 is evacuated to a vacuum degree of 1.5 Torr.
The semiconductor wafer 18 is placed on the electrodes 24 by drawing a vacuum to some extent. Next, plasma for gas excitation and plasma for adhesion prevention are generated in the reaction chamber 22. The former has a frequency of 13.56 MHz between the electrode 23 and the electrode 24 from the high frequency power supply 27.
It is generated by supplying a high frequency signal of z, and the latter is generated by supplying a high frequency signal of a similar frequency from the high frequency power supply 11C to the electromagnetic coil 11A as described in the first embodiment. While keeping this state at all times, WF ₆ and H ₂
When the mixed gas 27 is introduced into the reaction chamber 22, a W film is vapor-phase grown on the semiconductor wafer 18.

As described above, according to the parallel plate type W-CVD apparatus according to the second embodiment of the present invention, the plasma generator 11 is provided outside the reaction chamber 22, so that plasma for gas excitation is obtained. A plasma for adhesion prevention different from that can be generated with good controllability in the vicinity of the inner wall of the reaction chamber, the dissociation of the reaction product can be promoted, and the adhesion of the reaction product to the side wall of the reaction chamber 22 To be prevented.

As a result, as in the first embodiment, the cause of particle generation can be eliminated, and the reaction chamber 22
The number of times of cleaning the inside can be reduced. In addition, device characteristics and production yield can be improved, which contributes to improvement in reliability of the film forming apparatus and throughput thereof. In each of the embodiments of the present invention, the case where the plasma generator 11 is applied to the etching apparatus and the film forming apparatus has been described, but it is also applicable to the sputtering apparatus.

[0030]

As described above, according to the semiconductor manufacturing apparatus of the present invention, since the plasma generator is provided outside the reaction chamber, the second plasma different from the first plasma is supplied to the reaction chamber. Can be generated in the vicinity of the inner wall of the reaction chamber, and the adhesion of reaction products to the side wall of the reaction chamber can be prevented.

As a result, the cause of the generation of particles is removed, so that a highly reliable etching apparatus,
A plasma processing apparatus such as a film forming apparatus and a sputtering apparatus is provided, which largely contributes to improvement in throughput, device characteristics, and production yield.

[Brief description of drawings]

FIG. 1 is a configuration diagram of dry etching according to a first embodiment of the present invention.

FIG. 2 is a layout view of electromagnetic coils of a plasma processing apparatus according to each embodiment of the present invention.

FIG. 3 is a functional explanatory diagram of a plasma generator according to each embodiment of the present invention.

FIG. 4 is a functional explanatory diagram of plasma for adhesion prevention according to each embodiment of the present invention.

FIG. 5 is a parallel plate type WC according to a second embodiment of the present invention.
It is a block diagram of a VD device.

FIG. 6 is a configuration diagram of a plasma processing apparatus according to a conventional example.

[Explanation of symbols]

 11 ... Plasma generator, 11A, 11B ... Electromagnetic coil, 12, 22 ... Reaction chamber, 13 ... Cathode electrode, 14, 24 ... Heater / electrode, 15, 25 ... Reaction gas, 11C, 17, 27 ... High frequency power supply, 23 ... an electrode that also serves as a shower plate.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/31 C H05H 1/46 A 9216-2G

Claims (4)

[Claims] 1. A semiconductor manufacturing apparatus for depositing or etching a semiconductor substrate using a first plasma in a reaction chamber, wherein a plasma is generated to generate a second plasma different from the first plasma. A semiconductor manufacturing apparatus, wherein a container is provided outside the reaction chamber. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the plasma generator has a plurality of electromagnetic coils arranged around the outside of the reaction chamber. 3. The exciting current supplied to one of the electromagnetic coils is phase-shifted by 180 ° with respect to the exciting currents of other electromagnetic coils arranged adjacent to the electromagnetic coil. The semiconductor manufacturing apparatus according to claim 2. 4. The semiconductor manufacturing apparatus according to claim 2, wherein the second plasma is generated at least while the first plasma is being generated.