JPH11162946A - Semiconductor manufacturing equipment and substrate processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the attachment to a substrate of foreign matters generated in processing using plasma. SOLUTION: In a semiconductor manufacturing equipment, wherein high frequency power is applied between a lower electrode 4 and an upper electrode 5 to generate plasma 11 and then the surface of a semiconductor wafer 9 is processed, lines of magnetic force B are generated and allowed to diverge upwards in a region sandwiched between the lower electrode 4 and the upper electrode 5, and negatively charged foreign matters 15 floating on the surface of a sheath 14 are moved out of a region above the semiconductor wafer 9 along the lines of magnetic force B and then are eliminated. Even if the plasma 11 stops, the foreign matters 15 are prevented from falling onto the surface of the semiconductor wafer 9.

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 a substrate processing method, and more particularly to a technique which is effective when applied to the removal of foreign matter generated when processing a semiconductor substrate using plasma.

[0002]

2. Description of the Related Art Conventionally, low-temperature plasma is used as a method for treating a substrate such as a semiconductor wafer. That is, low-temperature plasma is used for depositing a silicon oxide film, a silicon nitride film, an amorphous silicon film, etc. on a semiconductor substrate, or for etching a silicon oxide film, a silicon nitride film, an amorphous silicon film, etc., deposited on a semiconductor substrate. Is used.

As described above, low-temperature plasma is frequently used in the process of manufacturing a semiconductor device because low-temperature plasma is generated by glow discharge of gas under reduced pressure and is in a thermal non-equilibrium state. In other words, the temperature of the neutral particles and the ion temperature are low, and the semiconductor substrate can be processed at a low temperature, despite the high electron temperature in the plasma and the high reactivity resulting therefrom. like this,
Regarding the application of low-temperature plasma to the manufacturing process of semiconductor devices, see, for example, an industrial book published on March 18, 1994,
This is described in detail in "Low Temperature Plasma Material Chemistry" edited by Yoshihito Nagata.

However, in a substrate processing method using low-temperature plasma, an excessive volume reaction is promoted due to high reactivity in a thermal non-equilibrium state, and a large amount of foreign matter is generated in a plasma space. Are known. References discussing the generation of such foreign matter include, for example, “Applied Physics”, Vol. 65, No. 6, (199)
6) and p594 to p600.

When a foreign substance is generated in the plasma space, the foreign substance adheres to the semiconductor substrate and causes a patterning defect of wiring or the like, or when the foreign substance is a conductive foreign substance,
This causes short-circuit failure between the already formed wirings, and further causes insulation failure due to the presence of foreign matter in the insulating film, and often appears as a fatal defect in the semiconductor device. Therefore, efforts have been made to reduce the generation of foreign substances or to remove them.

As a technique aimed at reducing the generation of foreign substances,
For example, there is a technique described in JP-A-6-84853. This technique is intended to transport foreign matter in the plasma to an exhaust system by changing the gas pressure, gas flow rate, and the like in the plasma, thereby preventing foreign matter from adhering to the semiconductor wafer.

[0007] For example, see Japanese Patent Application Laid-Open No. 58-14535.
There is also a technique described in Japanese Unexamined Patent Application Publication No. H10-260, 1993. In this technique, foreign matter (dust) adhering to a semiconductor wafer is charged with plasma, and then separated and removed by Coulomb repulsion by an electric field of opposite polarity applied to the semiconductor wafer.

[0008]

However, Japanese Patent Laid-Open No. 6-8 / 1994
In the technique disclosed in Japanese Patent No. 4853, since the gas pressure and the like are changed during the processing of the substrate, the conditions of etching or film deposition are changed, which affects processing characteristics or characteristics such as film thickness and film thickness distribution. In general, the pressure range of processing using low-temperature plasma is about 15 to 40 mTorr, and it is known that the gas flow in such a pressure region is a molecular flow. Therefore, there is a problem that the force required to move the foreign matter, that is, the fine particles, in question is not efficiently given by the molecular flow, and the foreign matter cannot be sufficiently moved.

Further, in the technique described in Japanese Patent Application Laid-Open No. 58-14535, when the foreign matter is conductive, the charge applied to the foreign matter leaks to the semiconductor wafer, and even if an electric field is applied to the semiconductor wafer. Can no longer repel foreign objects. Further, in this technique, plasma is used as a method for applying electric charge to foreign matter. However, not only when the foreign matter is a conductor, but also when the foreign matter is an insulator, the surface is made conductive by plasma, and only the foreign matter is applied. It is difficult to provide sufficient charge.

On the other hand, when foreign matter adheres to the substrate, it is practically conceivable to remove the foreign matter by cleaning the substrate and reduce the influence on the subsequent steps. And the cost is also unfavorable.

An object of the present invention is to provide a technique for suppressing adhesion of a foreign substance generated during processing using plasma to a substrate.

Another object of the present invention is to minimize the influence of the plasma on the processing itself when suppressing the adhesion of foreign substances, thereby effectively achieving the original purpose of the processing and simultaneously reducing the adhesion of foreign substances. It is in.

It is another object of the present invention to reduce the attachment of foreign matter to a substrate to eliminate a fatal defect in a semiconductor device, and to improve the yield and reliability of the semiconductor device.

It is another object of the present invention to reduce the number of necessary cleaning steps, reduce the load on the cleaning steps, shorten the steps, and improve cost competitiveness.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0016]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

(1) A semiconductor manufacturing apparatus according to the present invention comprises: a reaction chamber capable of maintaining the inside thereof at a reduced pressure; gas supply means for supplying gas to the reaction chamber; gas exhaust means for exhausting gas from the reaction chamber; It has a pair of electrodes installed horizontally in the reaction chamber and a power supply for supplying power to the electrodes, and ionizes gas in the reaction chamber maintained at a pressure of 1 atm or less by gas supply means and gas exhaust means with power. A semiconductor manufacturing apparatus that generates plasma between a pair of electrodes and processes a surface of a substrate provided on a lower electrode of the pair of electrodes using the plasma, and has a magnet outside a reaction chamber. The lines of magnetic force generated by the magnet diverge upward from the surface of the substrate in a region sandwiched between the pair of electrodes.

According to such a semiconductor manufacturing apparatus, the foreign matter generated in the plasma is effectively moved to the outside of the substrate,
Adhesion of foreign matter to the substrate can be reduced. Less than,
The mechanism by which foreign matter is moved to the outside of the substrate will be described.

In the foreign matter generated in the plasma, electrons adhere to the foreign matter due to collision with the electrons in the plasma, and the foreign matter is negatively charged. In the plasma, electrons having a small mass have a large amplitude due to the AC electric field, and ions do not move much due to the large mass. Therefore, it cannot be said that there are no positively charged foreign substances, but most of the foreign substances are negatively charged.

On the other hand, a plasma sheath (ion sheath) is formed at the interface between the plasma and the power supply side electrode which is insulated DC from the ground potential by a capacitor (blocking capacitor). Such a plasma sheath is generated when the electrode is negatively charged with respect to the plasma due to the difference in the moving speed between electrons and ions in the plasma.
Physically, an electric double layer is formed at the interface between the power supply electrode and the plasma, and most of the DC potential between the electrodes is applied to the plasma sheath. Therefore, positively charged ions in the plasma are accelerated by the electric field of the plasma sheath, and are incident on the power supply electrode side in a uniform direction. This is a so-called ion bombardment, which is used for anisotropic etching of the surface of the substrate provided on the power supply electrode side.

Here, the behavior of the negatively charged foreign matter in the plasma will be considered. As described above, most of the electrostatic potential between the electrodes is applied to the plasma sheath. For this reason, almost no potential drop occurs in the plasma region except the plasma sheath, that is, in the positive column portion. As a result, the foreign matter in the positive column region is not greatly affected by the electric field, falls downward under the influence of gravity, stops at the upper end of the ion sheath, and floats. This is because, since the electrode is negatively charged with respect to the plasma, the negatively charged foreign matter receives Coulomb repulsion between the electrode and the electrode and balances the dropping force.

When the plasma is stopped in such a situation, the plasma sheath disappears, the Coulomb repulsion acting on the foreign matter also disappears, and as described in the prior art, the foreign matter falls by gravity and adheres to the substrate surface.

However, in the present invention, during the plasma processing,
Magnetic lines of force diverging upward from the surface of the substrate are generated in a region sandwiched between the pair of electrodes. For this reason, even if the foreign matter as described above is generated, the foreign matter moves along the line of magnetic force and is removed to the outside of the region sandwiched between the pair of electrodes. As a result, even if the plasma is stopped, the foreign matter is eliminated by the magnetic field lines, so that the foreign matter does not fall on the substrate and does not adhere to the substrate surface. As a result, the yield and reliability of the semiconductor device are improved by reducing fatal defects of the semiconductor device due to the attachment of foreign matter, and the number of cleaning steps required for removing the foreign matter is reduced, thereby reducing the load on the cleaning process. And the cost competitiveness can be improved by shortening the process.

Here, the condition that the magnetic field lines diverge upward only needs to be satisfied at least in the region sandwiched between the pair of electrodes, and does not need to be satisfied in the entire reaction chamber. In other words, in the region between the pair of electrodes, magnetic lines of force having both a horizontal component directed toward the outer peripheral direction of the substrate and a vertical component directed upward from the substrate surface may be formed. Due to the action of the lines of magnetic force, foreign matter moves upward and in the outer peripheral direction of the substrate in the region sandwiched between the pair of electrodes, and is consequently removed from the upper region of the substrate.

Such lines of magnetic force can be generated by a cylindrical magnet centered on the vertical center axis of a pair of electrodes, and the vertical symmetry plane of the cylindrical magnet is 1 cm above the upper surface of the substrate. It can be installed below. Thus, a magnetic field diverging upward from the substrate surface can be generated.

(2) The semiconductor manufacturing apparatus of the present invention comprises: a reaction chamber capable of maintaining the inside thereof at a reduced pressure; gas supply means for supplying gas to the reaction chamber; gas exhaust means for exhausting gas from the reaction chamber; It has a pair of electrodes installed horizontally in the reaction chamber and a power supply for supplying power to the electrodes, and ionizes gas in the reaction chamber maintained at a pressure of 1 atm or less by gas supply means and gas exhaust means with power. A semiconductor manufacturing apparatus that generates plasma between a pair of electrodes and processes a surface of a substrate provided on a lower electrode of the pair of electrodes using the plasma, and has a magnet outside a reaction chamber. The lines of magnetic force generated by the magnet have a direction parallel to the surface of the substrate, and
A mechanism is provided in which the direction of the magnetic field lines rotates about the central axis of the substrate.

According to such a semiconductor manufacturing apparatus,
As in the case of (1), the foreign matter is excluded from the region between the pair of electrodes, and the adhesion of the foreign matter to the substrate surface can be reduced. That is, in the present invention, a magnetic field is applied only in the horizontal direction, and the magnetic field is rotated, so that the foreign matter moves to the outside of the outer periphery of the substrate and is removed. As a result, the yield and reliability of the semiconductor device are improved by reducing fatal defects of the semiconductor device due to the attachment of foreign matter, and the number of cleaning steps required for removing the foreign matter is reduced, thereby reducing the load on the cleaning process. And the cost competitiveness can be improved by shortening the process.

In the above (1) and (2),
The strength of the magnetic field generated by the magnet can be 100 Gauss or less at the surface of the substrate. As the strength of the magnetic field increases, the effect of foreign matter movement can be expected to be greater. On the other hand, plasma parameters such as plasma density and temperature are affected by the influence of the magnetic field, and processing conditions such as etching may change. Therefore, a sufficient effect of moving foreign matter can be expected, and the range of the magnetic field intensity where the influence of the plasma processing condition is small is 100 Gauss or less, preferably several Gauss to several tens Gauss.

(3) In the substrate processing method of the present invention, a power is supplied between a pair of horizontally held electrodes in a reaction chamber to generate plasma, and the reactivity of the processing gas dissociated by the plasma is utilized. A substrate processing method for processing the surface of the substrate held on the lower electrode of the pair of electrodes by applying a magnetic field diverging upward from the surface of the substrate in a region sandwiched between the pair of electrodes. The processing is performed, or the substrate is processed while applying a magnetic field having a direction parallel to the surface of the substrate and rotating in the direction about the central axis of the substrate.

According to such a substrate processing method, (1)
Or, since the plasma processing is performed while generating the magnetic field as described in (2), foreign substances generated during the processing are effectively eliminated outside the plasma (outside the region sandwiched between the electrodes), and the foreign substance surface of the substrate is removed. Can be prevented from adhering to

The strength of the magnetic field can be set to 100 gauss or less on the surface of the substrate.

Further, the magnetic field can be applied only for a time that is one fifth or less of the processing time immediately before stopping the plasma. As described above, since the magnetic field for removing foreign matter is applied only for a short time immediately before the stop of the plasma, a change in plasma processing conditions due to the influence of the magnetic field can be suppressed to a minimum. As a result, for example, the distribution of the etching rate can be reduced. The time immediately before stopping the plasma by applying the magnetic field may be, for example, about several seconds to about one minute when the plasma processing time is about 1 to 5 minutes.

The magnetic field can be applied after replacing the processing gas with a non-reactive gas without stopping the plasma. By thus applying the magnetic field only after replacing the processing gas with a non-reactive gas without stopping the plasma, it is possible to minimize the change in the plasma processing conditions due to the influence of the magnetic field, for example, The distribution of the etching rate can be reduced.

Further, it is possible to control the direction or magnitude of the magnetic field lines of the magnetic field according to the number of foreign substances detected by the foreign substance monitor. Thereby, the direction and magnitude of the magnetic field can be optimized so that the amount of foreign matters is minimized.

[0035]

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

(Embodiment 1) FIG. 1 is a sectional view showing an example of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

The semiconductor manufacturing apparatus according to the present embodiment
a, a reaction chamber 1 comprising an upper surface 1b and an inner wall 1c,
The reaction chamber 1 can be connected to another reaction chamber or a substrate transfer chamber via a gate valve 2.

The gas in the reaction chamber 1 can be evacuated to a high vacuum through an exhaust port 3 by a gas exhaust system such as a turbo molecular pump and an oil rotary pump. Further, gas is supplied to the reaction chamber 1 via a gas supply system such as a mass flow controller MFC and a valve V. In this embodiment, the case of the etching treatment is exemplified, and the gas may be an etching gas such as carbon tetrafluoride (CF ₄ ) and argon (Ar). However, since the present invention is not limited to the etching process, source gases for the film deposition process, such as silane (SiH ₄ ) and disilane (Si ₂ H)
₆ ) etc. may be supplied. By supplying these gases,
The gas pressure in the reaction chamber 1 is appropriately maintained by balancing the gas supply flow rate and the gas exhaust speed. The pressure can be adjusted by adjusting the conductance by a control valve built in the exhaust port 3 in addition to the gas flow rate. The adjusted gas pressure is several tens to several tens
00mTorr.

A lower electrode 4 and an upper electrode 5 are provided in the reaction chamber 1.

A high frequency power supply 7 is connected to the lower electrode 4 via a blocking capacitor 6. The lower electrode 4 is AC-connected to the high-frequency power source 7 by the action of the blocking capacitor 6, but is insulated from the high-frequency power source 7 in the DC direction, and thus is insulated from the ground potential in the DC direction. As a result, the lower electrode 4 is negatively charged with respect to the plasma, and a self-bias is applied.

The lower electrode 4 has a wafer push-up pin 8b.
Is provided, and a semiconductor wafer 9 as a substrate placed on the electrostatic chuck 8 is chucked by an electrostatic action. That is, the semiconductor wafer 9 includes the lower electrode 4
The main surface is held on the upper surface.

The high frequency power supply 10 is connected to the upper electrode 5. Since no capacitor is interposed between the upper electrode 5 and the high-frequency power supply 10, the upper electrode 5 is grounded in terms of direct current, and is not self-biased. In the present embodiment, a method using two power supplies, the high-frequency power supply 7 and the high-frequency power supply 10, has been described. However, the high-frequency power supply 10 is not used, that is, the upper electrode 5 is simply grounded, and only the high-frequency power supply 7 is used. May generate plasma. Further, the plasma may be controlled by adjusting the phases of the output powers of the high frequency power supply 7 and the high frequency power supply 10.

The output frequency of the high-frequency power supply 7 and the high-frequency power supply 10 can be, for example, 800 kHz to 40 MHz.
The frequency is not limited to this, and may be any frequency at which a sufficient self-bias is applied.

Using such a semiconductor manufacturing apparatus, a plasma 11 is generated between the lower electrode 4 and the upper electrode 5.

A quartz susceptor 12 is provided on the outer periphery of the lower electrode 4 and the upper electrode 5 to prevent abnormal discharge around the electrodes.

Further, in the semiconductor manufacturing apparatus of the present embodiment, the electromagnet 13 is arranged outside the reaction chamber 1. Since the electromagnet 13 is provided, it is possible to prevent foreign matter from adhering to the semiconductor wafer 9 due to magnetic lines of force generated by the electromagnet 13. As a result, the number of fatal defects in the semiconductor device due to the foreign matter can be reduced, and the yield and reliability of the semiconductor device can be improved. Further, it is possible to reduce the number of cleanings after the processing by the semiconductor manufacturing apparatus, and it is possible to reduce the load of the cleaning step. The mechanism for preventing the attachment of foreign matter will be described later.

The electromagnet 13 is a cylindrical magnet centered on the central axis of the semiconductor manufacturing apparatus (the central axis of the semiconductor wafer 9), and is constituted by two independent ring magnets in the figure. However, the present invention is not limited to the number of magnets at all, and is not limited to the number or shape of magnets as long as magnetic lines of force as described later are generated. Also,
Although the electromagnet 13 is illustrated in the present embodiment, a permanent magnet may be used.

Next, a mechanism for preventing foreign matter from adhering will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view showing the plasma and electrode portions. The right part of FIG. 2 shows a DC electric field distribution between the upper and lower electrodes.

In FIG. 2, the plasma 11 generated between the lower electrode 4 and the upper electrode 5 is indicated by a region surrounded by a dashed line for convenience. Although the boundary of the plasma 11 is not clear in practice, a sheath 14 is formed at the interface between the lower electrode 4 and the upper electrode 5 and the plasma 11. This sheath 14
Is the plasma sheath described above, and the plasma 1
This is caused by a self-bias generated in the lower electrode 4 due to the difference in the moving speed of the electrons and ions in 1. Therefore, most of the DC potential generated between the upper and lower electrodes is applied to the region of the sheath 14, and a DC potential gradient hardly occurs in the plasma 11. A potential gradient corresponding to the wall potential of the plasma is generated at the interface between the upper electrode 5 and the plasma 11. These states are shown in the potential distribution between the electrodes shown on the right side of FIG.

Since there is almost no potential gradient in the plasma 11, the foreign matter 15 generated in the plasma 11 descends by gravity and floats on the sheath 14.

If a magnetic field is applied in such a situation to generate magnetic field lines B as shown in the figure, the foreign matter 15 moves along the magnetic field lines B. The movement of the foreign matter 15 along the magnetic field lines B is such that the foreign matter 15 is negatively charged, and thermal current of the negatively charged foreign matter 15, vibration in plasma, vibration due to ion bombardment, or vibration of the sheath 14 causes a current to flow. This is caused by Lorentz force due to the interaction between the current and the magnetic field. Therefore, if the magnetic field is generated so as to form the magnetic field lines B diverging upward as shown in the figure, the foreign matter 15 that has moved along the magnetic field lines B is eliminated to the outside of the semiconductor wafer 9 and eventually the semiconductor wafer 9 Does not fall outside and adhere to the semiconductor wafer 9.
Thus, the adhesion of the foreign matter 15 to the semiconductor wafer 9 can be prevented by the action of the magnetic field.

The generation of the upwardly diverging magnetic field as described above can be obtained by a ring magnet such as the electromagnet 13 of the present embodiment. In a ring magnet, the magnetic field is the strongest at the center of the ring, and the magnetic field diverges in the vertical direction.Therefore, when applied to this embodiment, the vertical symmetry plane of the ring magnet, that is, the surface with the strongest magnetic field 14 or less. If such conditions are satisfied, the lines of magnetic force B are always diverging upward in the region of the plasma 11 sandwiched between the two electrodes, and the foreign matter 15
Can be excluded to the outside.

Since the thickness of the sheath 14 is usually 1 cm or less, it can be paraphrased that the vertical symmetry plane of the ring magnet is located below 1 cm above the surface of the lower electrode 4. The number of ring magnets may be one or two or more.

The strength of the magnetic field is determined by the semiconductor wafer 9
100 Gauss or less on the surface of The higher the magnetic field strength, the faster the foreign matter 15 is expected to move, but on the other hand, the processing parameters such as etching may be changed due to the influence of the magnetic field on the plasma parameters such as the density and temperature of the plasma 11. Therefore, a sufficient effect of moving the foreign matter 15 can be expected, and the range of the strength of the magnetic field having a small influence on the plasma 11 is 100 Gauss or less, preferably several Gauss to several tens Gauss.

Next, a plasma processing method using the above-described semiconductor manufacturing apparatus will be described. FIG. 3 is a flowchart illustrating an example of the substrate processing method according to the present embodiment.

First, the semiconductor wafer 9 is loaded into the reaction chamber 1 via the gate valve 2 (Step 101). The loaded semiconductor wafer 9 is placed on the lower electrode 4 and held by the electrostatic chuck 8.

Next, the residual gas in the reaction chamber 1 is exhausted by an exhaust means (vacuum pump) connected to the exhaust port 3, and the inside of the reaction chamber 1 is brought into a high vacuum state (step 102).

Next, gas is introduced while controlling the gas flow rate by the mass flow controller MFC. The gas is a processing gas for processing the surface of the semiconductor wafer 9, and is a mixed gas of carbon tetrafluoride and argon in the case of the etching exemplified in the present embodiment. Further, the gas exhaust speed is controlled by a control valve provided in the exhaust port 3, and the gas pressure in the reaction chamber 1 is controlled, for example, to 100 mTorr (step 103).

Next, the high-frequency outputs of the high-frequency power supplies 7 and 10 are turned on, and the high-frequency power is applied to the lower electrode 4 and the upper electrode 5. The frequency of the high frequency power is, for example, 13.56 M
Hz, and the high frequency power can be, for example, 500 W. Thereby, the plasma 11 is generated (Step 104).

By the generation of the plasma 11, the surface of the semiconductor wafer 9 is etched. After a predetermined time, for example, 5 minutes, the plasma 11 is stopped (step 106).
However, immediately before that, a magnetic field is applied to generate a magnetic field line B (step 105). The operation during this time will be described in detail with reference to FIG. FIG. 4 is a time chart showing the mutual relationship between high-frequency power and magnetic field generation.

At time t1, high frequency power is turned on. This corresponds to step 104 described above. Until time t2, the high-frequency power is kept on without applying a magnetic field, and the plasma is continuously generated. During this time, the surface of the semiconductor wafer 9 continues to be etched, and foreign matter 15 is generated in the plasma 11. However, as described above, the foreign matter 15
It floats on the top and does not fall on the surface of the semiconductor wafer 9. Further, since no magnetic field is applied during this time, the etching characteristics do not change.

At time t2, for example, four minutes after time t1, the output of the high-frequency power starts decreasing, and at time t3, the output of the high-frequency power becomes zero, and the plasma 11 stops completely. At the same time, a magnetic field is applied from time t2 to time t3. By applying a magnetic field, the foreign matter 15 is moved to the outside of the upper portion of the semiconductor wafer 9 by the above-described mechanism.
Since the plasma 11 has not disappeared from the time t2 to the time t3, the foreign matter 15 on the sheath 14 continues to float,
The foreign matter 15 does not fall on the semiconductor wafer 9. This prevents the foreign matter 15 from adhering to the semiconductor wafer 9.

By applying the magnetic field at such a timing, the foreign matter 15 can be effectively eliminated without being affected by the etching characteristics caused by the application of the magnetic field. The time between the time t2 and the time t3 is, for example, 10 seconds.

Next, the residual gas in the reaction chamber 1 is evacuated to a high vacuum (Step 107), the semiconductor wafer 9 is unloaded (Step 108), and the processing of this embodiment is completed.

According to the semiconductor manufacturing apparatus and the substrate processing method of the present embodiment, foreign matter 15 generated during plasma processing
Of the semiconductor device 9 on the surface of the semiconductor wafer 9, the number of fatal defects of the semiconductor device can be reduced, and the yield and reliability of the semiconductor device can be improved. Further, since the amount of foreign matter 15 attached to the semiconductor wafer 9 is small, the subsequent cleaning process is simplified,
For example, the number of times of cleaning can be reduced to reduce the process load. Furthermore, in this embodiment, since the application of the magnetic field is limited to a short period immediately before the stop of the plasma, the effect of the application of the magnetic field can be minimized and the processing can be performed stably without changing the processing conditions such as etching.

(Embodiment 2) FIG. 5 is a flowchart showing an example of a substrate processing method according to another embodiment of the present invention.

The semiconductor manufacturing apparatus used in the substrate processing method of the present embodiment is the same as the semiconductor manufacturing apparatus described in the first embodiment. Further, from the wafer load (step 101) of the substrate processing method of the present embodiment to the plasma ON (step 104), from the wafer load (step 101) of the substrate processing method of the first embodiment to the plasma ON (step 104). Is the same as Therefore, description of these parts is omitted.

In this embodiment, after the plasma is turned on (step 104), the gas is switched after a predetermined time has elapsed (step 205), and then a magnetic field is applied (step 206) to remove the foreign matter 15 from the semiconductor wafer 9. The plasma is removed from the top, and then the plasma is stopped (step 207).
The application of the high-frequency power for generating the plasma 11 is the same as in the first embodiment.

The operation during this time will be described in detail with reference to FIG. FIG. 6 is a time chart showing the interrelationship between the gas flow rate, the high-frequency power, and the magnetic field generation.

At time t1, the high frequency power is turned on. This corresponds to step 104. Until time t2, the high-frequency power is kept ON without applying a magnetic field to continuously generate plasma, and continue to flow carbon tetrafluoride and argon as etching gases. During this time, the semiconductor wafer 9
Surface is continuously etched, and foreign matter 15 is
Generate inside. However, the foreign matter 15 is floating on the sheath 14 as described above, and does not fall on the surface of the semiconductor wafer 9. Further, since no magnetic field is applied during this time, the etching characteristics do not change.

At time t2, for example, four minutes after time t1, the flow rate of the etching gas is started to decrease, and at time t3, the flow rate of the etching gas is reduced to zero. At the same time, at time t2, the flow rate of only the non-reactive gas, argon, is started to increase,
At time t3, the flow rate of the argon gas is set to a predetermined flow rate. That is, at time t3, only the non-reactive argon gas remains in the reaction chamber 1 and the plasma 11 is maintained, but the etching action hardly occurs.

Here, while maintaining the plasma 11, a magnetic field is applied from time t4. By applying a magnetic field, the foreign matter 15 is moved to the outside of the upper portion of the semiconductor wafer 9 by the above-described mechanism. During this time, the foreign matter 15 on the sheath 14 continues to float because the plasma 11 has not been extinguished, and the foreign matter 15 does not fall onto the semiconductor wafer 9. This prevents the foreign matter 15 from adhering to the semiconductor wafer 9.

Thereafter, at time t5, the high-frequency power starts to decrease, and the plasma 11 is stopped.

If a magnetic field is applied at such a timing, no etching action occurs when the magnetic field is applied,
The foreign matter 15 can be effectively removed without being affected by the etching characteristics caused by the magnetic field. The time between time t4 and time t5 may be, for example, 10 seconds.

According to the substrate processing method of the present embodiment,
Foreign matter 15 can be prevented from adhering to semiconductor wafer 9, and the effects described in the first embodiment can be obtained similarly.

(Embodiment 3) FIG. 7 is a sectional view showing an example of a semiconductor manufacturing apparatus according to still another embodiment of the present invention.

The semiconductor manufacturing apparatus of the present embodiment differs from the semiconductor manufacturing apparatus of the first embodiment in that the amount of foreign matter 15 in the plasma 11 is observed by the foreign matter monitor 17 through the window 16 and the observed amount is subjected to data processing. It has a function of controlling the direction and intensity of the magnetic force line B by controlling the current amount and the current direction of the electromagnet 13 by operating the magnet controller 19 after processing by the device 18.

The foreign substance monitor 17 can be exemplified by a particle counter using a laser beam, and the data processing device 18 can be exemplified by a computer system.

The method of controlling the direction and intensity of the magnetic field lines B can be controlled by changing the combination of the directions of the currents flowing through the respective magnets of the plurality of electromagnets 13 and the amount of current.

With such a semiconductor manufacturing apparatus, foreign matter 1
By controlling the electromagnet 13 so as to minimize the amount of 5, the direction and intensity of the magnetic field lines B can be optimized.

As described above, the invention made by the inventor has been specifically described based on the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the invention. Needless to say, it can be changed.

For example, in the first to third embodiments, the application period of the magnetic field is limited to a short period immediately before the stop of the plasma 11. However, the present invention is not limited to this.
It is also possible to apply the voltage during the entire period in which is generated or in some other period.

Further, in the above embodiment, the magnetic field in which the magnetic field lines B are diverged upward has been described. However, as shown in FIG. 8, a magnetic field such as the magnetic field lines B2 parallel to the semiconductor wafer 9 may be used. FIG. 8A is a top view illustrating another example of the semiconductor manufacturing apparatus, and FIG. 8B is a cross-sectional view of FIG. FIG. 8 shows only the main parts to make the drawing easier to see. In this case, the magnetic field lines B2 generated from the pair of magnets M3 are parallel to the semiconductor wafer 9, and the foreign matter 15 moves along the magnetic field lines B2. Further, the magnetic field lines B2 can be rotated. That is, a magnetic field is generated by the magnet M1 pair at a certain time, and the magnetic field is switched to the magnetic field generated by the magnet M2 pair at the next moment. Next, the magnetic field is switched by switching to the magnet M3 pair at the moment and further to the magnet M4 pair at the next moment. By generating the rotating magnetic field in this way, the foreign matter 15 can be more effectively moved to the outside of the semiconductor wafer 9 and eliminated. Needless to say, the substrate processing using such a semiconductor manufacturing apparatus can be applied to the method described in the first to third embodiments, and the foreign substance monitor 17 can be added.

[0084]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

(1) It is possible to prevent foreign substances generated during the processing using plasma from adhering to the substrate.

(2) In suppressing the adhesion of foreign matter, the influence of the plasma on the treatment itself can be minimized, and the adhesion of the foreign matter can be simultaneously reduced while effectively achieving the original purpose of the treatment.

(3) Adhesion of foreign substances to the substrate can be reduced to eliminate fatal defects of the semiconductor device, and the yield and reliability of the semiconductor device can be improved.

(4) The number of necessary cleaning steps can be reduced to reduce the load on the cleaning step, and the steps can be shortened to improve cost competitiveness.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a plasma and an electrode.

FIG. 3 is a flowchart illustrating an example of a substrate processing method according to an embodiment of the present invention.

FIG. 4 is a time chart showing the mutual relationship between high-frequency power and magnetic field generation.

FIG. 5 is a flowchart showing an example of a substrate processing method according to another embodiment of the present invention.

FIG. 6 is a time chart showing a mutual relationship among a gas flow rate, a high-frequency power, and a magnetic field generation.

FIG. 7 is a cross-sectional view illustrating an example of a semiconductor manufacturing apparatus according to still another embodiment of the present invention.

FIG. 8A is a top view illustrating another example of the semiconductor manufacturing apparatus, and FIG. 8B is a cross-sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 1a Lower surface 1b Upper surface 1c Inner wall 2 Gate valve 3 Exhaust port 4 Lower electrode 5 Upper electrode 6 Blocking capacitor 7 High frequency power supply 8 Electrostatic chuck 8b Wafer push-up pin 9 Semiconductor wafer 10 High frequency power supply 11 Plasma 12 Quartz susceptor 13 Electromagnet 14 Sheath 15 Foreign matter 16 Window 17 Foreign matter monitor 18 Data processing device 19 Magnet controller B Magnetic field line B2 Magnetic field line M1 to M4 Magnet MFC Mass flow controller V Valve

Claims (8)

[Claims] 1. A reaction chamber capable of maintaining the inside thereof at a reduced pressure, a gas supply means for supplying a gas to the reaction chamber, a gas exhaust means for exhausting a gas from the reaction chamber, and a horizontal installation in the reaction chamber. A pair of electrodes, and a power supply for supplying power to the electrodes, and ionizes the gas in the reaction chamber maintained at a pressure of 1 atm or less by the gas supply unit and the gas exhaust unit with the power. A semiconductor manufacturing apparatus that generates plasma between the pair of electrodes and processes a surface of a substrate installed on a lower electrode of the pair of electrodes using the plasma, wherein a magnet is provided outside the reaction chamber. And a magnetic field line generated by the magnet diverges upward from the surface of the substrate in a region sandwiched between the pair of electrodes. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the magnet is a cylindrical magnet centered on a vertical central axis of the pair of electrodes, and a vertical symmetry plane of the cylindrical magnet is A semiconductor manufacturing apparatus, which is provided so as to be lower than 1 cm above the upper surface of the substrate. 3. A reaction chamber capable of maintaining the inside thereof in a reduced pressure state, gas supply means for supplying gas to the reaction chamber, gas exhaust means for exhausting gas from the reaction chamber, and horizontally installed in the reaction chamber. Having a pair of electrodes and a power supply for supplying power to the electrodes, and ionizing the gas in the reaction chamber maintained at a pressure of 1 atm or less by the gas supply means and the gas exhaust means with the power. A semiconductor manufacturing apparatus that generates plasma between the pair of electrodes and processes a surface of a substrate installed on a lower electrode of the pair of electrodes using the plasma, wherein a magnet is provided outside the reaction chamber. Having, the lines of magnetic force generated by the magnet have a direction parallel to the surface of the substrate, and
A semiconductor manufacturing apparatus comprising a mechanism for rotating the direction of the line of magnetic force around a central axis of the substrate. 4. The semiconductor manufacturing apparatus according to claim 1, wherein a strength of a magnetic field generated by said magnet is 100 gauss or less on a surface of said substrate. . 5. A plasma is generated by supplying power between a pair of horizontally held electrodes in a reaction chamber, and a lower electrode of the pair of electrodes is generated by utilizing the reactivity of a processing gas dissociated by the plasma. A substrate processing method for processing a surface of a substrate held thereon, wherein a magnetic field diverging upward from a surface of the substrate in a region sandwiched between the pair of electrodes, or a magnetic field parallel to the surface of the substrate. A substrate processing method, comprising: processing a substrate while applying a magnetic field having a direction, the direction of which rotates around a central axis of the substrate. 6. The substrate processing method according to claim 5, wherein the intensity of the magnetic field is 100 gauss or less on the surface of the substrate. 7. The substrate processing method according to claim 5, wherein the magnetic field is applied only for a time equal to or less than one fifth of the processing time immediately before stopping the plasma, or The substrate processing method according to any one of the second configuration and the second configuration, wherein the processing gas is added only after replacing the processing gas with a non-reactive gas without stopping the plasma. 8. The substrate processing method according to claim 5, wherein the magnetic field controls a direction or a size of a magnetic field line according to the number of foreign substances detected by a foreign substance monitor. Substrate processing method.