JPH02260361A - Ion implantation apparatus - Google Patents

Abstract

PURPOSE:To carry out uniform ion implantation into trench inner walls by providing at least one of a tilting function to a sample to be ion-implanted, a rotating function, and olifra adjusting function. CONSTITUTION:A platen 9 is tilted by a motor 11 for tilting installed outside of an ion implantation chamber 8 through a rotary shaft 10 and the rotary position of the motor 11 for tilting is detected by a rotary encoder 12, and the detected rotary position is put as a feedback in the motor 11 for tilting and the rotation of the motor 11 is controlled to become a prescribed rotation. The speed of rotation of the platen 9 is measured by an origin sensor 16 and the origin of the rotary of the platen 9 is determined according to the measured value and thus the operation of a motor 14 for rotation is controlled. The orientation flat position of a sample (wafer) which is mounted on the platen 9 and ion-implanted is detected by an orientation flat sensor 15 and orientation flat position adjustment is carried out basing on the detected result.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is an ion implantation system that includes a parallel scanning system that performs parallel scanning of an ion beam and can be used for semiconductor manufacturing, material surface modification, surface analysis, etc. It is related to the device.

[Prior Art] As is well known, ion implantation technology performs impurity doping and material synthesis by accelerating ions and irradiating them onto the sample surface.Doping can be done without being affected by the condition of the sample surface. It is an extremely high-precision and clean impurity doping technology, and by taking advantage of this feature, LSI and ultra-LSI
It is used for manufacturing I elements, surface modification of materials, surface analysis, etc.

As an example of an ion implantation apparatus equipped with a parallel scanning system that performs parallel scanning of an ion beam, the present applicant has previously proposed an ion source A and an ion beam generated by the ion source A, as shown in FIG. 4 of the attached drawings. A mass spectrometry system B extracts ions with the required kinetic energy and mass from the ions, an acceleration system C consisting of an acceleration tube accelerates the extracted ions, a four-diameter focusing lens system, and a A first deflector E that removes energy neutral particles, a second deflector F that scans the ion beam in the X-Y direction, and a second deflector F that cancels out the spread angle of the ion beam deflected by the second deflector F. We have proposed a device consisting of a third deflector G that deflects the ion beam into a parallel ion beam, and a platen H that holds the sample (wafer) to be ion-implanted. As shown in FIG. 5, the first deflector E consists of a parallel plate type electrostatic constant-angle deflector that deflects the ion beam by about 7°, the second deflector F consists of a multipole electrode, and the third deflector F consists of a multipole electrode. The device G has a structure similar to the multipole pole of the second deflector 8F, and consists of multiple @electrodes that direct the direction of the ion beam directed to 1 by the second deflector F in a constant direction with respect to the sample surface. ing.

Ions to be used for implantation are selected from among the ions generated by the ion source A in the mass spectrometry system B, and a set energy is given to the selected ions in the acceleration system C. The energized ions are focused onto the input section of the first deflector E by a quadrupole focusing lens system. The ion beam entering the first deflector E is deflected by about 7 degrees, and high-energy neutral particles contained therein are removed. The ion beam from which neutral particles have been removed is scanned in the X and Y directions by the second deflector F, so that at the exit of the second deflector F, the ion beam has a maximum of 10
It has a spread angle of ”.

This spread angle is canceled by the deflection by the third deflector G, and the ion beam becomes parallel to the axis of the ion beam at the exit of the third deflector G, so that a parallel ion beam is implanted into the sample on the platen H. obtain.

The platen H is normally tilted by 7° when the axial direction of the ion beam is 0°. In the case of a highly integrated LSI, the platen H may be tilted at 0° without being tilted. Therefore, in any case, the platen 1 is fixed during ion implantation.

[Problems to be Solved by the Invention] When performing parallel scanning using the above-mentioned ion implantation apparatus in which the platen in the ion implantation chamber is fixed during ion implantation, parallel ions are generated as shown in FIG. Beam I
When the ions are incident on the wafer J at a certain angle, only a portion where ions are not implanted occurs due to the pattern formed on the surface of the wafer J. This is called a shadow effect, and has become a problem as wafers become increasingly fi4[1 in ion implantation technology and pattern widths become narrower.

In particular, in ultra-1.3T devices that require parallel ion beams with high density and high integration, the influence of the shadow effect on device characteristics becomes significant.

However, if the ion implantation angle is set to Oo in order to prevent the shadow effect, an axial channeling phenomenon occurs and uniform implantation cannot be obtained.

On the other hand, even if the injection angle is set to 7° to prevent the axial channeling phenomenon, a shadow effect occurs, and furthermore, if the orientation flat angle is Oo in this case, the surface channeling phenomenon occurs.
After all, uniform injection cannot be obtained.

Furthermore, as shown in FIG. 7, when a parallel ion beam I is implanted into the inner wall of the trench M, it is implanted into one side of the inner wall, but not into the other side of the inner wall. Ion implantation cannot be performed uniformly over the entire inner wall.

The present invention solves the problems associated with the previously proposed ion implantation apparatus, and aims to provide an ion implantation apparatus that is free from channeling phenomena and shadow effects and can uniformly implant ions even into the inner walls of trenches. The purpose is

[Means for Solving the Problems] In order to achieve the above object, an ion implantation apparatus according to the present invention tilts a sample to be ion-implanted so that the incident angle of the ion beam to the sample becomes a required angle. 1
- means, an orientation flat setting means for aligning the crystal axis direction of the sample, and a means for rotating the sample tI.

[Function] In the ion implantation apparatus of the present invention configured as described above, the tilting means tilts the ion beam at an angle of 0° to 6° with respect to the sample.
The sample to be ion-implanted is placed at a set angle with respect to the ion beam (e.g. 7°
), the orientation flat setting means sets the orientation flat angle by detecting the orientation flat position, and the rotating means rotates the sample, that is, the platen on which the sample is mounted, at a predetermined rotational speed. Therefore, even if the orientation flat angle is set to, for example, 0° by the orientation flat setting means, the platen is tilted by the chill 1 to means and the injection angle is set to 7°.
Each time the platen is rotated by the rotating means, ion implantation without shadow effect or uniform ion implantation into the inner wall of the trench can be performed without axial channeling or surface channeling.

[Embodiments] Examples of the present invention will be described below with reference to FIGS. 1 to 3 of the accompanying drawings.

FIG. 1 shows an ion implantation apparatus implementing the present invention, in which 1 is an ion source, 2 is an analysis magnet that extracts six ions with the required kinetic energy and mass from the ions from the ion source 1, and 3 4 is a quadrupole lens that focuses the ions accelerated through the acceleration section 3; 5 is an ion source 1, an analysis magnet 2, and an acceleration section 3; and a first deflector for removing neutral particles in the ion beam passing through the focusing lens 4, which is connected to an appropriate C power source (not shown). 6.7 is the second and third north direction 85 for parallel scanning,
These components are constructed substantially similar to those previously proposed as shown in FIG.

Further, in FIG. 1, reference numeral 8 denotes an ion implantation chamber, in which is placed a platen 9 on which a sample to be ion implanted is mounted, and this platen 9 is rotatably and tiltably provided as will be explained in detail later. It is being That is, the platen 9 is coupled via a rotation shaft 10 to a tilt motor 11 provided outside the ion implantation chamber 8.
A rotary encoder 12 is attached to 1, and the tilt motor 11 and rotary encoder 12 tilt the platen 9 via the rotation shaft 10, so that the ion beam can be incident on the sample at any angle in the range of 0° to 60°. It functions to set the angle of inclination of the sample to which ions are to be implanted so that the ions are incident at an angle.

Further, the platen 9 is connected to the rotation motor 1 via the rotation shaft 13.
4, and can be rotated by this rotation motor 14 at, for example, a maximum rotation speed of 10 RPS.

Furthermore, in FIG. 1, reference numeral 15 denotes an orientation flat sensor that determines the orientation flat angle, and is arranged around the platen 9.

Reference numeral 16 denotes an origin sensor that determines the origin of rotation of the platen 9.

In the illustrated apparatus, the platen 9 is tilted at a set angle (for example, 7 degrees) by a tilt motor 11 provided outside the ion implantation chamber 8 via a rotation shaft 10, and the rotational position of the tilt motor 11 at this time is is detected by the rotary encoder 12, and fed back to the tilt motor 41, so that the tilt motor 11 is controlled to perform a predetermined rotation.

The rotation speed of the platen 9 is measured by an origin sensor 16, and the origin of the rotation of the platen 9 is determined based on this measurement value, and the operation of the rotation motor 14 is controlled. The orientation flat position of the sample (wafer) to be ion-implanted that is mounted on the platen 9 is detected by the orientation flat sensor 15, and the orientation flat alignment of the wafer can be performed based on the detected orientation flat position. In this way, the platen 9 on which the sample to be ion-implanted is mounted can be provided with a tilt function, a rotation function, and an orientation flat alignment function.

Incidentally, in the illustrated embodiment, the platen has three functions of tilting, rotating, and aligning the orientation flat, but the platen may be configured to have one of these functions depending on the application of ion implantation. Even so, the intended purpose can be achieved. Further, instead of continuous rotation, the rotation of the platen 9 by the rotation motor 14 can be set to an arbitrarily set rotation of one rotation or less, that is, a rotation position.

Furthermore, the embodiment shown in FIG. 1 is a so-called single-end station construction in which the ion implantation chamber 8 is one room.
As shown in FIG. 2, the present invention naturally provides two deflection directions of +7° and -7° by switching the polarity of the DC voltage applied to the first deflector 5 for removing neutral particles from the ion beam. It is also possible to implement a dual-end station structure in which the second and third deflectors 6.7 are configured into two systems and the ion implantation chamber 8 is made into two chambers.

In this case, one end station will be an ion implantation chamber with a fixed platen angle as in the past, and the other end station will have a platen tilt function as in the embodiment shown in FIG. It is also possible to have at least one R function of a rotation function and an orientation flat alignment function.

Further, the deflector system for forming a parallel ion beam can perform the function of the first deflector by applying a bias potential to the second deflector, as shown by reference numeral 6'' in FIG. It is also possible to use an R4 model with a function to remove particles.

Furthermore, although the case has been described in which the second and third deflectors each consist of multipole electrodes, the following types of deflector systems may of course be used as long as they can generate parallel ion beams.

[Effects of the Invention] As explained above, the ion implantation apparatus according to the present invention includes an end station that can provide at least one of the functions of tilt R function, rotation function, and orientation flat alignment function to the sample to be ion implanted. Since it is combined with an ion implanter that can generate parallel ion beams, there is no channeling phenomenon or shadow effect for highly integrated samples such as VLSIs that require ion implantation using parallel ion beams. Uniform ion implantation can also be performed on the inner wall of the trench.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an ion implanter implementing the present invention, FIG. 2 is a schematic diagram showing another embodiment, and FIG. 3 is a schematic diagram of an ion implanter according to yet another embodiment of the present invention. 4 is a schematic perspective view showing the parallel scanning ion implantation device proposed earlier; FIG. 5 is a schematic diagram showing the structure of the parallel scanning system of the device in FIG. 4. View, 6th
7 and 7 are explanatory diagrams showing an example of ion implantation into a sample using a parallel ion beam. Figure middle 8: Ion implantation chamber 14: Rotation motor 9 nib platen 15: Orientation flat sensor 10: Rotation axis
16: Origin sensor 11: Tilt motor 12: Rotary encoder 13: Rotation axis Fig. 2F Fig. 4 Fig. 5 Fig. 7

Claims (1)

[Claims] 1. In an ion implantation apparatus equipped with a parallel scanning system that performs parallel scanning of the ion beam, means for tilting the sample to be ion-implanted so that the incident angle of the ion beam with respect to the sample becomes a required angle, and An ion implantation apparatus comprising at least one of a means for adjusting a direction and a means for rotating a sample.