JP2690725B2 - Ion implanter - 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 implantation apparatus for implanting an ionized substance into an object to be implanted such as a semiconductor wafer.

[0002]

2. Description of the Related Art First, the basic structure of an ion implantation apparatus will be described with reference to FIG. First, the independent beam controller 2 adjusts each parameter required for beam generation, and the ion source 3 generates an ion beam. Next, the ion beam is accelerated by the acceleration voltage 9 and enters the mass analyzer 10. Then, the ion beam is subjected to mass analysis by an electromagnetic magnet, and only the necessary ion beam is guided to the object 6 to be injected set in the injection site 5, and the object 6 is injected. A beam blocking plate 4 controlled by the end station controller 1 is provided in front of the object 6 to be implanted, and the ion beam is opened / blocked here to start / stop the implantation of the object 6 to be implanted. Further, the end station controller 1 controls the transport system 7 that sets and collects the injection target 6 at the injection site 5. In addition, the dose counter 8 receives a signal for starting the injection from the end station controller 1, extracts the beam current during the injection from the injection site 5, counts the dose amount, confirms whether the target injection amount has been reached, and stops the injection. Send a signal to the end station controller 1.

FIG. 8 is a flow chart of the implantation process until the uninjected object 6 in the ion implantation system of FIG. 7 is implanted and recovered at the implantation site 5. It should be noted that the confirmation of conditions necessary for injecting a vacuum or the like is not related to the present invention and will not be described.

The implantation process by the ion implantation system of FIG.
First, in step A of FIG. 8, the operator sets beam conditions to the beam controller 2, and the beam controller 2 controls the ion source 3 based on the beam conditions to create a high current beam. Next, the operator issues an injection start command to the end station controller 1, and in step B, the end station controller 1 confirms the injection start command. When the injection start command is confirmed, the transport system 7 controlled by the end station controller 1 in step C sets an uninjected substance in the injection site 5 and confirms it in step D. When the setting to the implantation site 5 is completed, in step E, the end station controller 1 opens the beam blocking plate 4 in the closed state, so that the ion beam that has been blocked up to now is to be implanted 6
And the injection is started. At the same time, in step F, the injection start signal from the end station controller 1 is received, and the dose counter 8 starts counting the dose amount.

Next, in step G, it is confirmed by the dose counter 8 whether the target implantation amount has been reached. When the target implantation amount is reached, the dose counter 8 sends an implantation stop signal to the end station controller 1. In step H, the end station controller 1 closes the beam blocking plate 4 to block the ion beam and stop the implantation. Next, in step I, the carrier system 7 collects the injected object 6 from the injection site 5. Next, at step J, the end station controller 1 confirms whether or not there is another uninjected object 6. If there is an uninjected object 6, the process returns to step C and the flowchart of this injection process is repeated.
If all the injected objects 6 have been injected and there is no uninjected material, this injection process ends.

This is a series of flow until the injected object 6 is injected and recovered. FIG. 9 is a time chart of this injection process, and the alphabet written inside is FIG.
Is a step name of the flowchart of FIG.

As can be seen from the time chart of FIG.
The ion beam generated during this implantation process is a high-current beam having the same intensity during the implantation regardless of whether the implantation is stopped. As described above, when the high current beam constantly flows, the beam blocking plate is greatly worn.

As a technique for solving the problems of this conventional technique, it is possible to apply the technique disclosed in Japanese Patent Laid-Open No. 2-5350. The content of this technique will be described below. FIG. 10 shows Japanese Patent Laid-Open No. 2-5
A technique for preventing the ion beam from reaching the beam blocking plate 4 in the technique disclosed in the publication 350 will be described. This technology has the following four points. The purpose can be achieved by controlling the ion source 3 to output and stop the ion beam. The object can be achieved by controlling the exciting current of either the front or rear mass analyzer 10a or 10b so that the ion beam cannot pass through the mass analyzer. By providing the rear mass analyzer 10b after the rear accelerator 11 and turning off the rear accelerator 11, the ion beam cannot pass through the rear mass analyzer 10b and the object can be achieved. The object can be achieved by providing the electrostatic deflection plate 12 in front of the beam blocking plate 4 and controlling the voltage applied to the electrostatic deflection plate 12 to jump up the beam.

[0009]

In the conventional ion implantation apparatus, the beam blocking plate for blocking the ion beam is heavily worn by the beam, and it is necessary to frequently replace the beam blocking plate. The reason is that in recent years, the high-energy, high-current beam required for ion implanters is always generated with the same intensity regardless of whether the injection is stopped or when the injection is stopped. This is because

When the technique described in JP-A-2-5350 is applied, the beam can be turned off, but the throughput of the ion implanter is reduced. The reason is that in the case of, since the ion source is controlled and the ion beam is completely stopped, it is necessary to raise the arc of the ion source in order to start up to the target beam current again. It takes more than twice as much time to start up the beam as to raise it.

In this case, if the excitation current is once controlled so that the ion beam cannot pass through the mass analyzer, precise control is required to accurately extract the peak of the ion beam when the beam is passed again. This is because it takes a long time.

Further, by applying the above-mentioned technique of Japanese Patent Laid-Open No. 2-5350, the area occupied by the ion implantation apparatus is increased and the cost is increased. The reason is that by providing a post-stage accelerator, a rear mass analyzer, and an electrostatic deflection plate, the path of the ion beam, that is, the beam line length, becomes longer, and the power supply and controller that drive them are installed. The area occupied by the ion implanter becomes large. Needless to say, the cost increases due to the provision of each of them, and it is very difficult to newly install and remodel.

It is an object of the present invention to extend the periodical replacement frequency of the beam blocking plate in the ion implantation apparatus, reduce the cost and improve the operation rate of the apparatus.

[0014]

The ion implantation apparatus of the present invention is characterized in that an ion beam having an original intensity is generated only during the implantation, and the intensity of the ion beam is weakened when the implantation is stopped. More specifically, the ion station automatically controls the ion source based on the signal sent from the end station controller that determines the current implantation or the termination of the implantation and outputs an ion beam intensity signal to the beam controller. And a beam controller for controlling the intensity of the beam.

The end station controller which has judged that the implantation is stopped sends a small current beam forming signal to the beam controller, and the beam controller weakens the generation of the ion beam based on the signal. Therefore, when the injection is stopped, the collision of the large current beam with the beam blocking plate in the closed state is drastically reduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of an ion implantation apparatus of the present invention. This ion implanter is shown in FIG.
As shown in FIG. 3, the ion source receives the signal from the end station controller 1 which outputs a high current beam forming signal or a small current beam forming signal to the beam controller 2 by judging whether the injection is in progress or stopped, and the ion source receives the signal from the end station controller 1. A beam controller 2 for controlling the intensity of the ion beam is provided.

FIG. 2 is a flowchart of the implantation process until the uninjected object 6 in the ion implantation apparatus of FIG. 1 is implanted and recovered at the implantation site 5. It should be noted that the confirmation of conditions necessary for injecting a vacuum or the like is not related to the present invention and will not be described. In the implantation process by the ion implantation apparatus of FIG. 1, first, in step A of FIG. 2, the operator sets a beam condition in the beam controller 2, and the beam controller 2 controls the ion source 3 based on it to create a high current beam. Next, the operator issues an injection start command to the end station controller 1, and in step B, the end station controller 1 confirms the injection start command. When the injection start command is confirmed, in step C, the end station controller 1 sets the beam controller 2
The beam controller 2 controls the ion source 3 according to the signal to generate a small current beam, and suppresses the ion beam to a small current beam. At the same time, in step D, the transport system 7 controlled by the end station controller 1 transfers the uninjected substance 6 into the injection site 5.
The setting is started, and the confirmation is performed in step E. When the setting at the implantation site 5 is completed, in step F, the end station controller 1 sends a signal for forming a large current beam to the beam controller 2, and the beam controller 2 controls the ion source 3 in accordance with the signal to make the ion beam a large current beam. To return to.

Next, in step G, the end station controller 1 opens the beam blocking plate 4 so that the high current beam reaches the object 6 to be injected and the injection is started.
At the same time, in step H, the dose counter 8 receives an injection start signal from the end station controller 1 and the dose counter 8 starts counting the dose amount. Next, in step I, the dose counter 8 confirms whether the target implantation amount has been reached. When the target injection amount is reached, the dose counter 8 stops the injection.
A stop signal is sent to the end station controller 1, and in step J, the end station controller 1 closes the beam blocking plate 4 to block the ion beam and stop the implantation.

Next, in step K, the end station controller 1 sends a signal for forming a small current beam to the beam controller 2, and the beam controller 2 controls the ion source 3 according to the signal to suppress the ion beam to a small current beam. At the same time, in step L, the end station controller 1 controls the transport system 7 to recover the injected injection target 6 from the injection site 5. Next, in step M, the end station controller 1 confirms whether or not there is another uninjected object 6. If there is an uninjected object 6, the process returns to step D and the flow chart of this injection process is repeated. All the injected objects 6 have been injected, and if there is no uninjected material, this injection process ends.

FIG. 5 is a time chart showing changes in beam current and the like for each step of the flowchart of FIG. From this time chart, it can be seen that a large current beam is generated during the injection and is suppressed to the small current beam when the injection is stopped. In addition, when suppressing the ion beam to a small current beam, it is set to the minimum position where the arc of the ion source 3 can be stably maintained, and 1.0% for the phosphorus beam and the Hiso beam.
The weaker mA is about 0.2 mA for a boron beam. This depends on the implantation conditions, but it is about 10 to 10
The beam current was 30%, and the wear of the beam blocking plate 4 could be reduced by this reduction amount, and the replacement frequency could be extended three times or more. These beam current values are those of the high current ion implanter.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a diagram showing a second embodiment of the ion implantation apparatus of the present invention. As shown in FIG. 3, this ion implanter controls a transport timer 1a for measuring the time required to reach the end of the transport of the implantation target 6 and an ion source 3 inside the end station controller 1 to control a large current from a small current beam. The beam recovery time storage 1b is provided for storing the time until the beam is returned.

FIG. 4 is a flow chart of an implantation process in which the unimplanted object to be implanted in the ion implantation apparatus of FIG. 3 is implanted and recovered at the implantation site 5. The steps A to D in FIG. 4 of the implantation process by the ion implantation apparatus in FIG. 3 are the same as those in the first embodiment, and will be omitted. In step D, when the injecting object 6 is started to be set in the injection site 5 by the transport system 7, in step F, the end station controller 1 changes from the small current beam to the large current beam already stored in the beam recovery time memory 1b. And the time (BT) until the ion source 3 is controlled and returned and the injected object 6
Time (H)
T) are compared, and when they are the same time, in step G, the end station controller 1 sends a signal for forming a high current beam to the beam controller 2, and the beam controller 2 controls the ion source 3 according to the signal. Return the ion beam to a high current beam. As a result, when the high-current beam returns to 100%, it is confirmed that the injection target 6 has been set in the injection site 5 at step E, and immediately after that, the injection can be started at step I. Since steps H and I are the same as those in the first embodiment, description thereof will be omitted.

According to the second embodiment, the time loss due to the restoration of the large current beam can be minimized to improve the throughput, and the effect can be confirmed by the time chart shown in FIG.

[0024]

As described above in detail, the first effect of the present invention is that the abrasion of the beam blocking plate due to the ion beam can be suppressed low. As a result, the frequency of exchanging the beam blocking plate is extended, the cost of consumable parts is reduced, and the maintenance frequency is reduced due to the extension of the exchange frequency, and the operating rate of the ion implantation apparatus is improved. The reason is that the generation of the ion beam is suppressed to a low level when the implantation is stopped, and the collision of the large current beam with the beam blocking plate is drastically reduced.

The second effect is that the wear of the filament of the ion source can be kept low. As a result, the replacement frequency of the ion source is extended, the cost of consumable parts is reduced, and the replacement frequency is extended, which reduces maintenance work and improves the operating rate of the ion implantation apparatus. The reason is that the generation of the ion beam is suppressed to a low level when the implantation is stopped, so that the filament sputtering by the arc of the ion source is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an ion implantation apparatus of the present invention.

2 is a flow chart illustrating the injection stroke of FIG. 1. FIG.

FIG. 3 is a diagram showing a second embodiment of the ion implantation apparatus of the invention.

FIG. 4 is a flow chart illustrating the injection stroke of FIG.

5 is a diagram showing a time chart of the injection process of FIG.

6 is a diagram showing a time chart of the injection process of FIG.

FIG. 7 is a diagram showing an example of a conventional ion implantation apparatus.

8 is a flow chart illustrating the injection stroke of FIG. 7. FIG.

9 is a diagram showing a time chart of the injection process of FIG.

FIG. 10 is a diagram showing another example of a conventional ion implantation device.

[Explanation of symbols]

 1 End Station Controller 1a Transport Timer 1b Beam Recovery Time Memory 2 Beam Controller 3 Ion Source 4 Beam Blocking Plate 5 Injection Site 6 Injectables 7 Transport System 8 Dose Counter 9 Acceleration Voltage 10 Mass Spectrometer 10a Front Mass Spectrometer 10b Rear mass spectrometer 11 Rear accelerator 12 Electrostatic deflection plate

Claims (3)

(57) [Claims] 1. In an ion implantation apparatus for implanting an ionized substance into an object to be implanted such as a semiconductor wafer, an ion beam having an original intensity is generated only during the implantation, and the intensity of the ion beam is weakened when the implantation is stopped. An ion implanter characterized by: 2. An ion beam generated by an ion source is analyzed by a mass spectrometer to extract a desired ion beam, and in an ion implanter for implanting this ion beam into an object to be implanted, it is determined whether the ion beam is being implanted or the implantation is stopped. An end station controller that outputs a large current beam forming signal or a small current beam forming signal to the beam controller, and a beam controller that receives the signal from this end station controller and controls the ion source to control the intensity of the ion beam The ion implantation device is characterized in that. 3. The end station controller has a transfer timer for measuring the remaining time until the end of the transfer of the injected object, and a time for controlling the ion source to return from a small current beam to a large current beam. 3. The ion implantation apparatus according to claim 2, further comprising a beam return time storage unit storing therein.