JPH10275586A - Ion implantation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely grasp ion beam and scan execution state by outputting invert signals respectively when a material holder is inverted from forward to backward movements and vice versa, reading outputs from each ion beam current detector in response to those invert signals, and comparing it with a predetermined ion beam current reference conditions. SOLUTION: An invert signal output part in a driver circuit 41 of a motor M1 outputs invert signals respectively when a holder 2 is inverted from up to down directions and vice versa. When an invert signal exists, it is triggered, a controller 7 reads an ion beam current detected by each ion beam current detector 5. Based on a read ion beam current, each of the adjacent beams are compared each other, when the maximum difference of that comparison result is within a predetermined permissible range as ion beam current reference conditions, it judges that an ion beam scan is normally performed, and if it is outside the range, processing is halted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ion implantation for articles such as wafers for semiconductor devices and ion implantation for surface modification of articles such as various machine component bases and tool bases. To an ion implanter.

[0002]

2. Description of the Related Art When an ion implantation apparatus performs ion beam irradiation while scanning an ion implantation object with an ion beam, the ion beam is swung in one direction and a second direction crossing the one direction by the action of an electric field. Scanning of goods has been done. In addition, a hybrid scanning method in which an ion beam is swung in one direction and an article holder supporting an ion implantation target article is moved in a direction crossing the one direction to perform ion implantation on the article is also adopted.

In the case of employing the hybrid scan system, in order to irradiate the entire surface of the article with ions to be ion-implanted, each part of the surface to be ion-implanted must cross the ion beam swung in one direction. . For this reason, conventionally, an article holder for supporting the article to be ion-implanted is supported by an arm, and the arm is reciprocally driven by a motor via an appropriate transmission mechanism, and the motor is controlled with a high degree of rotation angle. A pulse motor that can be used to move the holder forward or backward
By counting the number of pulse signals applied to the pulse motor, it is determined that the holder has moved by a desired amount, that is, so that all parts of the surface to be ion-implanted of the article supported by the holder cross the ion beam scanning direction. Make sure you have moved.

[0004]

However, when the drive system of the article holder including the motor has an error in the operation accuracy or a failure occurs in a part of the drive system, the number of pulse signals can be accurately counted. Also, all parts of the ion implantation target surface of the article may not move so as to cross the ion beam scanning direction, and the ion beam scanning of the article may not be performed normally.

[0005] If the ion implantation process is continued by relying on the pulse count in spite of the occurrence of an abnormality in the ion beam scanning as described above, wasteful work is continued, and the ion implantation target is expensive. If so, a great deal of damage will occur. Therefore, the present invention sets the ion beam to 1
An ion implantation apparatus of a hybrid scan type for performing ion implantation on an article by swinging the article holder in a direction to move the article holder supporting the article for ion implantation in a direction crossing the one direction. An object of the present invention is to provide an ion implantation apparatus that can determine whether beam scanning has been performed normally or not more accurately than before.

[0006]

According to an ion implantation apparatus of the present invention for solving the above-mentioned problems, an ion beam is swung in one direction.
An ion implantation apparatus of a hybrid scan type for implanting ions into an article by moving an article holder supporting an article to be ion-implanted in the direction crossing the one direction, and reciprocatingly driving the article holder in the transverse direction. A drive unit, a plurality of ion beam current detectors arranged along the one direction behind the reciprocating path of the article holder in the ion beam irradiation direction, and when the article holder reverses from forward movement to backward movement. Means for outputting an inversion signal when inverting from the backward movement to the forward movement, and reading the output from each of the ion beam current detectors in response to the inversion signal, and setting the read ion beam current in advance. Means for determining whether or not the ion beam scan for the ion implantation target article has been normally performed by comparing with the ion beam current reference condition. It is characterized by that example.

[0007] The ion implantation apparatus according to the present invention comprises:
It also includes an ion doping apparatus. In general, the plurality of ion beam current detectors may be arranged in one direction in which the ion beam is swung from a region behind a central portion of the reciprocating path of the article holder to both sides thereof.

According to the ion implantation apparatus of the present invention, the ion implantation target article supported by the article holder is moved in one direction in which the ion beam is swung by driving the article holder by the holder driving section. Moved across.
At that time, in order to perform ion implantation on the entire ion implantation target region of the article, each part of the region is moved across one direction in which the ion beam is swung, and the entire region is irradiated with the ion beam, Ion implantation is performed.

In the ion implantation process, the inversion signal output means outputs an inversion signal when the holder is inverted from the forward movement to the backward movement and when the holder is inverted from the backward movement to the forward movement. On the other hand, during the ion implantation process, the ion current detectors arranged behind the movement path of the holder, which are released from the overlap with the holder in the ion beam irradiation direction, are directly irradiated with the ion beam, and the The detector detects a large ion beam current as compared to an ion beam current generator still partially or entirely overlapping the holder.

The means for judging whether or not the ion beam scanning has been normally performed on the article to be ion-implanted is performed in response to the inversion signal, in other words, by using the inversion signal as a trigger signal for each of the ion beam currents. The output from the detector is read, and the read ion beam current is compared with a predetermined ion beam current reference condition to determine whether or not the ion beam scan for the ion implantation target article has been performed normally.

As described above, according to the ion implantation apparatus of the present invention, the output of the ion beam current detector read by the means for judging whether or not the ion beam scanning has been normally performed is based on the ion implantation target article supported by the holder. Corresponding to the actual ion beam scan state, so that it is possible to know whether or not the ion beam scan has been normally performed more accurately than in the past. It is possible to avoid continuous useless ion implantation processing and wasting a large number of expensive ion implantation target articles.

According to the ion implantation apparatus of the present invention,
In the case where the article holder is tilted at a predetermined angle from a position perpendicular to the ion beam in order to inject an ion by tilting the article with respect to the ion beam, a holder projection behind the holder in the ion beam irradiation direction according to the tilt angle of the holder. Since the area changes and the rate at which the ion beam current detector is exposed to the ion beam changes, the means for determining whether or not the ion beam scan has been performed normally depends on the fact that the holder (and therefore the article) It can also be applied to determining whether or not the beam is arranged at a predetermined inclination angle with respect to the beam. In this case, an ion beam current reference condition for the determination may be set.

[0013] As a more specific example of the ion implantation apparatus of the present invention, the driving section of the article holder includes a forward / reverse rotatable pulse motor serving as a reciprocating drive source of the holder, and the inversion signal. Output means for outputting the inversion signal at a timing when the pulse signal supplied to the motor switches from the forward rotation pulse signal to the reverse rotation pulse signal and at a timing when the reverse rotation pulse signal switches to the forward rotation pulse signal Can be mentioned.

The means for judging whether or not the ion beam scanning of the article to be ion-implanted has been normally performed may be an output portion corresponding to each of the ion beam current detectors in the read ion beam current detector output. Are compared with each other, and when the maximum difference among the comparison results is within an allowable range predetermined as the ion beam current reference condition, it is determined that the ion beam scanning has been performed normally, and the allowable When the value is out of the range, an ion implantation apparatus that is determined to be abnormal can be cited. In obtaining the maximum difference, for example, for the output portion corresponding to each ion beam current detector, the output difference between each adjacent one is directly obtained, or the output ratio is obtained by obtaining the output ratio between each adjacent one. The difference can be obtained indirectly, and the maximum difference may be obtained from the output difference.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a schematic configuration of an example of an ion implantation apparatus according to the present invention. FIG. 2 is a diagram showing a schematic configuration of a portion of the ion implantation apparatus shown in FIG. 1 for determining whether the ion beam scan including the ion implantation target article support holder 2 is normal or abnormal is performed.

The ion implantation apparatus shown in FIG.
1. A mass analyzer 12 for selecting a predetermined ion species from an ion beam emitted by an ion source 11, an analysis slit 13 for selectively passing a predetermined ion species out of ions exiting the analyzer 12, a slit An ion accelerating tube 14 for accelerating the ions passing through 13, a quadrupole lens (so-called Q lens) 15 for converging an ion beam composed of ions accelerated by the accelerating tube 14, And a scanning device 16 for scanning in one direction X (see FIG. 2).

The end station 17 includes a target chamber provided with an article holder (target table) 2 for supporting an article W to be ion-implanted in the ion implantation process.
And a substrate transfer means (not shown) for loading and unloading substrates. As shown in FIGS. 2 and 3, the holder 2 is supported by one end 31 of the arm 3 formed bifurcated. As shown in FIG. 3A, the holder 2 has an arm member 21 at the center on the back surface. The arm member 21 is fitted to the forked portion of the arm end 31 and is rotatably supported by the shaft 22. ing. The shaft 22 is fixed to the arm member 21 but can rotate with respect to the arm end 31. Further, a pulse motor M2 is fixed to the side surface of the arm end 31, and the shaft 22 can thereby be rotated forward and reverse. Therefore, as shown in FIG. In this operation, the vehicle can be tilted from the neutral position P1 to a desired angle. This neutral posture P1 is a posture in which the support surface of the ion implantation target article W of the holder 2 is perpendicular to the ion beam irradiation direction Ix. As shown in FIG. 2, the motor M2 is supplied with a pulse signal from the driver circuit 42 and rotates forward or backward.

The arm 3 extends downward from the holder 2 and is held and guided by a guide 32 in the form of a groove rail so that it can be moved up and down. The guide 32 may be a roller or the like, and may be any as long as it can guide the arm 3 with little backlash. Arm 3
A rack gear 33 is provided on one side surface of the gear, and a pinion gear 34 in a fixed position is engaged with the rack gear 33.
The pinion gear 34 can be rotated forward and reverse by a pulse motor M1.
Can reciprocate up and down the maximum stroke L. Note that arm 3
The mechanism for raising and lowering 2 is not limited to the rack and pinion system, and another lifting mechanism may be employed. The reciprocating motion of the holder 2 may be a linear motion, a swing motion, or the like.

The motor M1 rotates forward in response to the forward rotation pulse signal supplied from the driver circuit 41, thereby raising the arm 3 and therefore the holder 2, and thus the reverse rotation pulse supplied from the driver circuit 41. It reverses in response to a signal, which allows the arm 3 and thus the holder 2 to be lowered. In FIG. 2, the holder position indicated by the solid line is the lower limit position of the holder 2, and the holder position indicated by the two-dot chain line at the top is the upper limit position of the holder 2. The holder 2 can reciprocate up and down within the range of the maximum stroke L between the upper limit and the lower limit.

A plurality of ion beam current detectors 5 are arranged in a single row from the area behind the center of the reciprocating path of the holder 2 to the left and right thereof, and a current detector row 50 is formed. As described above, the ion beam is scanned by the scanning device 16.
2, the ion beam current detectors 5 are arranged in the one direction X so that the ion beam current detectors 5 can receive ion beam irradiation when the holder 2 is not obstructed.

Further, the endmost ion beam current detector 5
An ion beam current detector 6 for detecting an ion dose (ion implantation amount) is also disposed outside the device. Each ion beam current detector here uses a Faraday cup. The current data detected by each ion beam current detector 5 and the ion beam current detector 6 for detecting the ion dose are sent to the implantation controller 7.

The injection controller 7 has a central processing unit (CPU), and based on an instruction from a host computer (not shown) for monitoring and controlling the operation of the entire ion implantation apparatus, a driver circuit 41 for the motor M1 and a motor. M2
To output a drive command signal of normal rotation or reverse rotation to the driver circuit 42, and to stop the ion implantation process as described later when the ion beam scan for the ion implantation target article W is not performed normally. , And outputs a signal for turning on the abnormality alarm device 8. Further, it reads the current data detected by the ion beam current detector 6 for detecting the ion dose, and performs an output necessary to obtain a desired ion implantation amount based on the data.

More specifically, the injection controller 7
Includes means 71, 72 shown in a block diagram in FIG. That is, if there is an input of an inversion signal to be described later, in response thereto, in other words, the ion beam current reading means 71 for reading the detection current from each ion beam current detector 5 using the signal as a trigger signal and the read ion Means 72 for comparing the beam current with a predetermined ion beam current reference condition to determine whether or not the ion beam scanning of the ion implantation target article W has been performed normally.
Contains.

The ion beam current reference condition can be input and set from the host computer or the like according to the ion implantation process. The ion beam current reference condition may be set in the implantation controller 7 (for example, the determination means 72) by providing a condition setting unit. Also, a fixed value may be set from the beginning. The inversion signal is sent to the injection controller 7 from an inversion signal output unit included in the driver circuit 41 of the motor M1.
The inversion signal output unit outputs the pulse signal supplied to the motor M1 when the pulse signal for normal rotation is switched from the pulse signal for reverse rotation to the pulse signal for reverse rotation and when the pulse signal for reverse rotation is switched to the pulse signal for normal rotation. An inversion signal is output based on each of the forward rotation pulse signals.

The inversion signal is generated internally by the injection controller 7 at the timing of instructing the motor M1 to rotate forward and reverse, and can be recognized internally, for example, directly by the means 71. It may be. When the pulse signal switches from the forward rotation pulse signal to the reverse rotation pulse signal, the holder 2 rises for ion implantation into the article W and then switches to the lowering operation, and the reverse rotation pulse signal changes to the forward rotation pulse signal. When switching to
This is a time when the operation is switched to the ascending operation after the holder 2 descends for ion implantation into the article W.

Here, the ion beam irradiation direction Ix (FIG. 3)
5 (A) to 5 (A) to 5 (C) show the current detector outputs corresponding to the overlapping state of the holder 2 and the current detector row 50 in FIG.
An example is shown in (C). In the state of FIG. 5A, the holder 2 is completely separated from the row 50, and all the detectors 5 receive ion beam irradiation. Therefore, the currents detected by the respective detectors are substantially equal and large. In the state shown in FIG. 5B, about 1/4 of the holder 2 is overlapped with the row 50, and the detection currents of the detectors are hidden behind the holder 2 from those at both ends which are sufficiently irradiated with the ion beam. Gradually getting smaller. In the state shown in FIG. 5C, the holder 2 is located at the center of the reciprocating path, and the current detected by each detector gradually increases from the both ends receiving the ion beam irradiation to the one hidden behind the holder 2. It is getting smaller.

The determination means 72 compares each of the adjacent parts with respect to the output part corresponding to the current detector 5 based on the data sent from the ion beam current reading means 71, and compares the comparison results. When the maximum difference D (see the example of FIG. 5D) is within an allowable range predetermined as the ion beam current reference condition (for example, 10% of the larger of adjacent ones), the ion beam scanning is normal. If it is out of the allowable range, it is determined to be abnormal, and if it is determined to be abnormal, a processing stop command signal is output to stop the ion implantation processing, and an abnormality alarm such as a buzzer is output. The container 8 is operated.

According to the ion implantation apparatus described above, ions are generated and extracted in the ion source 11. The extracted ions pass through the mass analyzer 12 so that predetermined ion species draw a predetermined motion trajectory. Subsequently, the predetermined ion species selectively pass through the analysis slit 13 and are accelerated by an ion acceleration tube 14. Then Q lens 15
While being swung in one direction X by the scanning device 16, irradiation is performed to ion-implant an ion implantation target article W (for example, a semiconductor device substrate) previously held in the article holder 2 at the end station 17.

On the other hand, the article W supported by the article holder 2
Is moved so as to cross the one direction X in which the ion beam is swung by raising and lowering the holder 2 by operation of the motor M1. At this time, in order to perform ion implantation on the entire ion implantation target region of the article W, each part of the region is driven to reciprocate up and down so as to cross the one direction X in which the ion beam is swung. Irradiation and ion implantation are performed. The amount of ion implantation is controlled based on the ion beam current detected by the current detector 6.

In the ion implantation process, the motor M
The inversion signal output unit in one driver circuit 41 outputs an inversion signal when the holder 2 is inverted from rising to falling and when the holder 2 is inverted from falling to rising. On the other hand, during the ion implantation process, the respective outputs of the ion current detectors 5 arranged behind the holder 2 fluctuate depending on the degree of overlap with the holder 2 as described with reference to FIG.

Here, the process of determining whether or not the ion beam scanning has been normally performed by the implantation controller 7 and the process related thereto will be described with reference to the flowchart shown in FIG. Initially, it waits for the start of ion implantation. When the ion implantation is started, it waits for the inversion signal input, and when there is the inversion signal input, it is used as a trigger and then detected by each ion beam current detector 5. The current ion beam current is read (steps S1, S2, S3). Next, with respect to an output portion corresponding to the current detector 5 based on the read ion beam current, each adjacent one is compared with each other,
The maximum difference D among the comparison results (see the example in FIG. 5D)
Is within an allowable range predetermined as the ion beam current reference condition (for example, 10% of the larger of adjacent ones), it is determined that the ion beam scanning has been performed normally, and the inversion signal is again waited for (step S4). ,
S5, S2). However, if it is out of this allowable range, it is determined that there is an abnormality, a processing stop command signal is output, and the abnormality alarm 8 is operated (steps S5, S6, S7).

In this state, the operator must retry the ion implantation process or immediately perform a process for checking the drive mechanism of the holder 2 and the like. As described above, according to the ion implantation apparatus, the output from the ion beam current detector 5 read by the implantation controller 7 corresponds to the actual ion beam scanning state of the ion implantation target article W supported by the holder 2. Therefore, it is possible to more accurately know whether or not the ion beam scan has been performed normally, and to continue useless ion implantation processing despite the occurrence of an abnormality in the ion beam scan, It is possible to avoid wasting many ion implantation target articles.

Further, according to this ion implantation apparatus, the article holder 2 is tilted with respect to the ion beam to implant ions by tilting the article W to the attitude P1 perpendicular to the ion beam (FIG. 3).
(See FIG. 6B), the holder projection area behind the holder 2 in the ion beam irradiation direction Ix is set to A1 according to the inclination angle of the holder 2 as shown in FIG.
To A2, and the rate at which the row 50 of the ion beam current detector 5 is exposed to the ion beam changes. Therefore, if the upper and lower limit positions of the holder 2 and the distance between them are predetermined and constant, and if the holder 2 operates as such, the injection controller 7 determines whether the scanning of the article by the ion beam has been performed normally. It is also possible to determine whether or not the article W is arranged at a predetermined inclination angle with respect to the ion beam by the same method as that for determining whether or not the article W is disposed. However, in this case, it is necessary to set the ion beam current reference condition for the determination to that condition, which can be set from the host computer or the like.

[0034]

As described above, according to the present invention, the ion beam is swung in one direction, and the article holder supporting the article to be implanted is moved in a direction crossing the one direction, thereby implanting ions into the article. And a hybrid scan type ion implantation apparatus that performs the above-described operation, and can more accurately know whether or not the ion beam scanning of the ion implantation target article has been normally performed.

Further, in the ion implantation apparatus of the present invention, the means for determining whether or not the ion beam scan has been normally performed on the article to be ion-implanted is performed by performing the ion implantation by tilting the article to be ion-implanted with respect to the ion beam. Further, the present invention can be applied to knowing whether or not the article is arranged at a predetermined inclination angle with respect to the ion beam.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an ion implantation apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a portion of the ion implantation apparatus shown in FIG. 1 for determining whether ion beam scanning including an ion implantation target article holder is normal or abnormal in ion beam scanning.

FIG. 3A is a rear view of an article holder and a part of an arm supporting the article holder, and FIG. 3B is a view showing a state in which the article holder can be tilted.

FIG. 4 is a block diagram of an ion beam current reading unit in the implantation controller and a unit for determining whether ion beam scanning is normal or abnormal.

FIGS. 5A to 5C are diagrams showing outputs of the respective ion beam current detectors according to the overlapping state of the article holder and the ion beam current detector row in the ion beam irradiation direction, respectively. FIG. 2D is a diagram for explaining an example of a method for determining whether the ion beam scanning is normal or abnormal.

FIG. 6 is a diagram showing a change in a holder projected area behind the holder when the article holder is inclined from a posture perpendicular to the ion beam irradiation direction.

FIG. 7 is a flowchart showing a process of determining whether or not the ion beam scan is normal or abnormal and a process related thereto by the implantation controller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ion source 12 Mass analyzer 13 Analysis slit 14 Ion accelerating tube 15 Quadrupole lens 16 Scanning device 17 End station 2 Article holder 22 Axis W Ion implantation object 3 Holder support arm 31 One end of arm 32 Guide 33 Rack gear 34 Pinion gear M1 Holder raising / lowering pulse motor 41 Driver circuit for motor M1 M2 Pulse motor for tilting holder 41 Motor M2 driver circuit 5 Ion beam current detector 50 Current detector array 6 Ion beam current detector 7 for detecting ion dose amount 7 Injection controller 71 Ion beam current reading means 72 Scan normal / abnormal judgment means 8 Abnormal alarm

Claims (3)

[Claims] 1. A hybrid scan type ion implantation apparatus in which an ion beam is swung in one direction, and an article holder supporting an article to be implanted is moved in a direction crossing the one direction to implant ions into the article. A drive unit for reciprocatingly driving the article holder in the transverse direction, and a plurality of ion beam current detectors arranged along the one direction behind the reciprocating path of the article holder in the ion beam irradiation direction; Means for outputting an inversion signal when the article holder is inverted from forward movement to backward movement and when the article holder is inverted from backward movement to forward movement, and an output from each of the ion beam current detectors in response to the inverted signal. Is read, and the read ion beam current is compared with a predetermined ion beam current reference condition to perform ion beam scanning on the ion implantation target article. Ion implantation apparatus characterized by comprising means for determining whether or not successful. 2. The article holder driving section includes a forward / reverse rotatable pulse motor serving as a reciprocating drive source of the holder, and the inversion signal output means outputs a pulse signal supplied to the motor. 2. The ion implantation apparatus according to claim 1, wherein the inversion signal is output at a timing when switching from the diversion pulse signal to the reverse rotation pulse signal and at a timing when switching from the reverse rotation pulse signal to the forward rotation pulse signal. 3. An output part corresponding to each of the ion beam current detectors in the output of the ion beam current detector which has been read, compares the adjacent parts with each other, and determines the maximum difference among the comparison results. And determining that the ion beam scanning has been performed normally when the current value is within an allowable range predetermined as the ion beam current reference condition, and determining that the ion beam scanning is abnormal when the current value is out of the allowable range. Or the ion implanter according to 2.