JP3149486B2 - Ion processing apparatus and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion processing apparatus for irradiating a substrate with an ion beam in a vacuum and performing processing such as ion implantation, such as an ion implantation apparatus.
More specifically, the present invention relates to an improvement in means for reducing the charging of the substrate and the contamination on the substrate.

[0002]

2. Description of the Related Art FIG. 6 is a view partially showing an example of a conventional ion processing apparatus. This apparatus is basically configured to irradiate a substrate (for example, a wafer) 6 held by a holder 4 housed in a vacuum vessel (not shown) with an ion beam 2 and to perform a process such as ion implantation. Have been.

[0003] The holder 4 may be a wafer disk for batch processing or a platen for single-wafer processing.
The illustrated one is an example of the former case, in which a plurality of substrates 6 are mounted and rotated at high speed and translated in a vacuum vessel.

A Faraday system is formed on the path of the ion beam 2, and receives secondary electrons 14 emitted from the ion beam 2 when the ion beam 2 hits the holder 4 or the substrate 6, and receives the secondary electrons 14 to ground. A Faraday cup (also called a Faraday case) 10 for preventing escape and a suppressor electrode 8 having a negative potential for preventing the emitted secondary electrons 14 from escaping to the upstream side are provided on the front side of the holder 4, and in this example, the holder 4 is provided outside. A catch plate 12 is provided on the rear side of the holder 4 for receiving the ion beam 2 instead of the translation when the translation is performed.

[0005] Then, the holder 4, the Faraday cup 10
The catch plate 12 and the catch plate 12 are electrically connected in parallel to each other and connected to the beam current measuring device 16 so that the beam current of the ion beam 2 can be accurately measured.

[0006]

In the ion processing apparatus as described above, the surface of the substrate 6 is irradiated with the ion beam 2, especially when the ion beam 2 has a large current and the surface of the substrate 6 is insulated. In the case of an object, there is a possibility that a problem such as discharge occurs due to positive charging.

As a countermeasure against this, there is an idea that secondary electrons 14 emitted from the holder 4 or the like accompanying the irradiation of the ion beam 2 are repelled to the substrate 6 on the holder 4. As described above, the bias power supply 18 is inserted between the holder 4 and the Faraday cup 10 or the like, and a positive potential (for example, several volts to
Means of applying a voltage of about several tens V to pull back the secondary electrons 14 have been proposed.

However, in this means, since the potential of the holder 4 is fixed, there is little effect on the secondary electrons 14 having various energies. If the bias power supply 1
Even if the potential of the holder 4 is changed by changing the voltage of the electrode 8, the energy of the secondary electrons 14 and the amount of the emitted electrons change very quickly (this is because the ion beam 2 hits the holder 4 and the substrate 6 And the holder 4 rotates at a high speed), it is difficult to make the potential of the holder 4 follow this, and the potential of the holder 4 remains unchanged. . Therefore, conventionally, the charging of the substrate 6 cannot be effectively reduced by using the secondary electrons 14 emitted from the holder 4 as described above.

On the other hand, in the above-described apparatus, the ion beam 2 hits the holder 4 or the substrate 6 so that the holder 4
Particles spatter out of the substrate 6 and the deposited film adheres to the inner wall of the Faraday cup 10, and when a large amount of the sputtered particles peels off from the wall, particles (dust) adhere to the surface of the substrate 6, increasing contamination. There was also the problem of doing.

Therefore, the present invention can reduce the charging phenomenon of the substrate due to the irradiation of the ion beam by effectively utilizing the secondary electrons emitted when the ion beam hits the holder, etc. It is a main object of the present invention to provide an ion processing apparatus capable of suppressing generation of particles at the substrate and reducing contamination on a substrate.

[0011]

In order to achieve the above-mentioned object , one of the ion processing apparatuses according to the present invention is provided on the inner wall of the Faraday cup as described above, in a plate-like shape covering the inner wall.
Alternatively, a tubular metal liner, which is divided into a plurality of parts and electrically insulated from each other and from the Faraday cup, is detachably attached.

[0012]

According to the above construction, secondary electrons emitted from the holder and the like accompanying the ion beam irradiation enter the surface of the metal liner, and the metal liner is electrically insulated. Biased to a negative potential by electrons. This potential is automatically biased in response to a change in the energy or emission amount of the secondary electrons, even if the change is fast. Due to this negative bias, secondary electrons from the holder and the like are automatically turned back toward the holder. If the substrate on the holder is positively charged with the ion beam irradiation, the secondary electrons are automatically supplied to the positively charged portion by being attracted by the charge and cancel the charge. Thereby, the charging phenomenon of the substrate due to the ion beam irradiation can be effectively reduced.

Further, a deposited film of sputtered particles generated from a holder or the like due to ion beam irradiation adheres to the surface of each metal liner covering the inner wall of the Faraday cup. Since each of these metal liners is removable, by replacing or removing them as appropriate, cleaning
Generation of particles inside the Faraday cup can be suppressed, and contamination to the substrate can be reduced.

[0014]

FIG. 1 is a sectional view partially showing an ion processing apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a sectional view taken along line BB of FIG. Parts that are the same as or correspond to those in the conventional example of FIG. 6 are denoted by the same reference numerals, and differences from the conventional example will be mainly described below.

In this embodiment, a metal liner 20 divided into a plurality of parts is placed on the surface facing the inner wall of the Faraday cup 10 and the holder 4 as described above so as to cover the inner wall and the facing surface. It is attached electrically insulated from the cup 10. Each metal liner 20 is detachably supported by an insulator 22.

Further, in this embodiment, in order to more reliably prevent the substrate 6 from being positively charged due to the ion beam irradiation, a filament 30 is provided on the side wall of the Faraday cup 10, and primary electrons 31 extracted from the filament 30 on the opposite surface. Supplying the electron shower (secondary electron) 32 emitted from the metal liner 20 (20a) to the substrate 6 on the holder 4 can be used in combination with the metal liner 20 (20a). It is not indispensable, and it is optional to provide it.

More specifically, the metal liner 20 on the inner wall of the Faraday cup 10 is divided into a plurality (three stages in the illustrated example) in the traveling direction of the ion beam 2. The one on the most upstream side has a cylindrical shape as shown in FIG. The same applies to the most downstream one. In the middle one, the metal liner 20a where the primary electrons 31 from the filament 30 hits is made into one piece as shown in FIG. 3 and connected to the Faraday cup 10 with an electric wire 21 or the like, and Leave at potential. This is because if the metal liner 20a is left floating, it is negatively biased by the primary electrons 31 and it becomes difficult for the primary electrons 31 to enter. As shown in FIG. 3, the metal liner 20 other than the metal liner 20 a in the intermediate portion has the Faraday cup 10 excluding the emission part of the primary electrons 31.
Is covering the inner wall. However, when the filament 30 is not provided, the intermediate metal liner 20 may have a simple tubular shape like the upper and lower metal liners. The metal liner 20 on the surface facing the holder 4 has a single annular plate shape.

In order to prevent the secondary electrons 14 emitted from the holder 4 or the like from passing through the gap between the metal liners, it is preferable to form a maze structure as shown in FIG. Preferably, this makes it possible to more completely prevent the secondary electrons 14 from escaping into the Faraday cup 10, and to more completely prevent contamination of the Faraday cup 10 by sputtered particles.

It is preferable that each insulator 22 be invisible from the ion beam irradiation surface on the holder 4, so that the insulator 22 can be prevented from being contaminated by sputtered particles. Further, in order to more reliably prevent contamination of each insulator 22 by sputtered particles, a cover 28 may be put on each insulator 22 as shown in FIG. 5, for example.
In the figure, reference numeral 26 denotes a screw for fixing the metal liner 20;
24 is an insulator.

According to the above configuration, the secondary electrons 14 emitted from the holder 4 and the substrate 6 due to the ion beam irradiation,
The metal liner 20 enters the surface of the metal liner 20 and
Are electrically insulated, and are biased to a negative potential by the secondary electrons 14. This potential is automatically biased in response to changes in the energy or the amount of emitted secondary electrons 14, even if the changes are fast. Due to this negative bias, the secondary electrons 14 from the holder 4 and the like are automatically turned back toward the holder 4.
If the substrate 6 on the holder 4 is positively charged with the ion beam irradiation, the secondary electrons 14 are automatically supplied to the positively charged portion by the charge and cancel the charge. . Thereby, the charging phenomenon of the substrate 6 due to the ion beam irradiation can be effectively reduced.

In addition, the holder 4 is irradiated with the ion beam irradiation.
The deposited film formed by sputter particles generated from the above-mentioned method adheres to the surface of each metal liner 20 covering the inner wall of the Faraday cup. Since each of the metal liners 20 is detachable, by appropriately replacing or removing the metal liner 20 and cleaning it, it is possible to suppress generation of particles inside the Faraday cup and reduce contamination to the substrate 6. Moreover, in this case, the operation is much simpler than removing and cleaning the Faraday cup 10 itself, so that the maintenance operation time can be reduced.

Each of the metal liners 20 may be left in an insulated state as described above, or an electric wire may be connected to each of the metal liners 20 and connected to the outside of the vacuum vessel via a vacuum seal portion. It is also possible to apply an independent potential to each of the required metal liners 20 using an external power supply or a resistor. If the potential is switched in accordance with, for example, the substrate 6 to be processed, the device can be used as an apparatus. Flexibility is improved.

Although the holder 4 is a wafer disk for batch processing in the above example, it may be a platen for single-wafer processing as described above.

[0024]

According to the first aspect of the invention, the metal liner provided on the inner wall of the Faraday cup is caused by the secondary electrons emitted from the holder or the like with the irradiation of the ion beam.
Moreover, even if there is a change in the energy or emission amount of this secondary electron, it is automatically biased to a negative potential in accordance with the change,
With this negative bias, the secondary electrons can be repelled toward the holder and supplied to the positively charged substrate with the irradiation of the ion beam. As a result, the charging phenomenon of the substrate can be effectively reduced by effectively utilizing the secondary electrons.

Further, the deposited film of sputtered particles generated from the holder or the like due to the irradiation of the ion beam adheres to the surface of each metal liner covering the inner wall of the Faraday cup, and each metal liner is detachable. , By replacing or removing this as appropriate and cleaning
Generation of particles inside the Faraday cup can be suppressed, and contamination to the substrate can be reduced. According to the invention described in claim 2, the Faraday cup
The metal liner provided on the inner wall
The secondary electrons emitted from the holder, etc.
Automatic even if there is a change in the energy or emission amount of secondary electrons
Correspondingly, it is biased to a negative potential,
Ias drives secondary electrons back to the holder,
Supply to positively charged substrate with on-beam irradiation
be able to. As a result, the above secondary electrons are effectively used
To effectively reduce the charging phenomenon of the substrate.
You. Moreover, the part where the primary electrons from the filament hit
The metal liner attached to the Faraday cup
Pneumatic connection and the metal liner is the primary electron
Negative electron bias makes it difficult for the primary electrons to enter
Can be prevented from becoming a filament
From the metal liner by being hit by primary electrons from
Effective use of emitted electron showers (secondary electrons)
To positively charge the substrate due to ion beam irradiation.
Can be prevented. Also, with ion beam irradiation
Deposited film due to sputtered particles generated from the holder, etc.
Attached to the surface of each metal liner that covers the inner wall of the Faraday cup
Each metal liner
Faraday cup by removing and cleaning
It suppresses the generation of particles inside and
Termination can be reduced. Claim 3
According to the invention described above, the metal provided on the inner wall of the Faraday cup
The liner is released from a holder etc. with ion beam irradiation.
The emitted secondary electrons, and the energy of this secondary electrons
Automatically responds to changes in energy and emissions.
Biased to a negative potential.
Backs out the next electron toward the holder, for ion beam irradiation
Accordingly, it can be supplied to a positively charged substrate. So
As a result, the above-mentioned secondary electrons are effectively used to charge the substrate.
The phenomenon can be effectively reduced. Also, ion
Sputtered particles generated from holders etc. due to beam irradiation
The metal film covering the inner wall of the Faraday cup
Each metal liner will adhere to the surface of the inner
When it becomes dirty, remove it and replace or clean it.
Particles inside the Faraday cup
Suppression of contamination and reduction of substrate contamination
Can be done. According to the fourth aspect of the invention,
The metal liner on the inner wall of the Faraday cup
Secondary electrons emitted from the holder etc.
Changes in the energy and emission of this secondary electron
Automatically biases negative potentials accordingly
This secondary bias causes secondary electrons to move toward the holder.
Turns back and is positively charged with ion beam irradiation
It can be supplied to the substrate. As a result, the secondary electrons
To effectively reduce substrate charging phenomena.
Can be made. Moreover, the primary power from the filament
Pull the metal liner attached to the part
Electrically connected to the day cup and the metal liner
Is negatively biased by the primary electron and the primary
Can prevent the child from becoming difficult to enter.
And the primary electrons from the filament hit
Electron shower emitted from metal liner (secondary electron)
Is effectively used to correct the substrate
Charging can be more reliably prevented. Also, ion
Sputtered particles generated from holders etc. due to beam irradiation
The metal film covering the inner wall of the Faraday cup
Each metal liner will adhere to the surface of the inner
When it becomes dirty, remove it and replace or clean it.
Particles inside the Faraday cup
Suppression of contamination and reduction of substrate contamination
Can be done.

[Brief description of the drawings]

FIG. 1 is a sectional view partially showing an ion processing apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is a cross-sectional view showing an example of a structure for eliminating a gap between metal liners.

FIG. 5 is a sectional view showing an example of a cover of the insulator.

FIG. 6 is a sectional view partially showing an example of a conventional ion processing apparatus.

[Explanation of symbols]

 2 Ion beam 4 Holder 6 Substrate 10 Faraday cup 14 Secondary electron 20 Metal liner 22 Insulator 30 Filament

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 37/317 C23C 14/48 H01J 37/04 H01L 21/265

Claims (4)

(57) [Claims] An apparatus for treating a substrate held by a holder holding the substrate by irradiating the substrate with an ion beam in a vacuum, wherein a beam current measuring beam is provided upstream of the holder. In a device having a Faraday cup, a plate-shaped or tubular metal liner that covers the inner wall of the Faraday cup, which is divided into a plurality of pieces and is electrically insulated from each other and from the Faraday cup. ,
An ion processing apparatus which is detachably attached. 2. A substrate held by a holder for holding a substrate.
The substrate by irradiating the substrate with an ion beam in a vacuum
A device for measuring beam current on the upstream side of the holder.
Have a Faraday cup and beside the Faraday cup
With filaments that generate primary electrons on the wall
In this case, the inner wall of the Faraday cup is covered with the inner wall.
A plurality of electrically insulated plate or tubular gold
Metal liner and this multiple metal
In the liner, primary electrons from the filament strike
The metal liner attached to the barrel is the Faraday
Electrically connected to the cup, and the remaining metal liner is
It is electrically insulated from the Faraday cup
Ion treatment device. 3. A substrate held by a holder for holding a substrate.
The substrate by irradiating the substrate with an ion beam in a vacuum
A device for measuring beam current on the upstream side of the holder.
In the case of having a Faraday cup, the Faraday
A plate-like or tubular metal wrapper covering the inner wall of the cup
Inner, divided into multiple parts, and
And take an electrically insulated one from the Faraday cup.
And when this metal liner gets dirty,
Ion characterized by removal and replacement or cleaning
How to use the processing unit. 4. A substrate held by a holder for holding a substrate.
The substrate by irradiating the substrate with an ion beam in a vacuum
A device for measuring beam current on the upstream side of the holder.
Have a Faraday cup and beside the Faraday cup
With filaments that generate primary electrons on the wall
In this case, the inner wall of the Faraday cup is covered with the inner wall.
A plurality of electrically insulated plate or tubular gold
A metal liner is attached, and this multiple metal
In the liner, the filament Primary electrons from the
The metal liner attached to the barrel is the Faraday
Electrically connected to the cup, and the remaining metal liner is
Keep this metal electrically insulated from the Faraday cup
Remove and replace or clean the liner when it gets dirty.
A method for using an ion processing apparatus, comprising performing a sweep.