JPH117915A - Ion implanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion implanter of a sheet capable of uniformly implanting ions to a semiconductor wafer with an emitting direction of an ion beam fixed. SOLUTION: An emitting direction of an ion beam is fixed. Ions are implanted to a semiconductor wafer 1 while the semiconductor wafer 1 is mechanically moved laterally and vertically. For this purpose, an oscillating mechanism is provided for reciprocally and laterally moving a wafer platen 2, which holds the semiconductor wafer 1 therein, at a constant speed inside a vacuum container 9, and a vertically driving mechanism is provided for vertically moving the wafer platen 2 at another constant speed.

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, and more particularly, to an ion implantation apparatus in which an ion beam is emitted in a fixed direction and an ion implantation is performed on a semiconductor wafer while mechanically moving the semiconductor wafer in the horizontal and vertical directions. .

[0002]

2. Description of the Related Art There are two types of ion implanters, a batch type and a single wafer type. A high energy ion implanter,
The high current ion implanter is generally of a batch type, and the medium current ion implanter is usually of a single wafer type.

As disclosed in, for example, US Pat. No. 4,733,091, a batch-type ion implanter rotates a whole wafer disk at a low speed while rotating a wafer disk on which a plurality of semiconductor wafers can be mounted at one time. A method of moving in a vertical (up / down) direction is general. Such a method is suitable for mass production of storage devices such as DRAMs. However, in the case of development and production of high-value-added products such as processors (arithmetic devices), which are expected to increase in the future, single-wafer processing is required. It has been pointed out that the formula is more efficient.

A single-wafer ion implantation apparatus employed in a medium-current ion implantation apparatus is disclosed, for example, in Japanese Patent Application Laid-Open No. 6-28313.
As disclosed in Japanese Patent Publication No. 0, a type in which a semiconductor wafer is mechanically moved at a low speed in a vertical (up / down) direction while scanning an ion beam at a high speed in a horizontal direction by an electric field method or a magnetic field method is generally used. .

[0005]

However, the single-wafer ion implantation apparatus requires an electrostatic field generator or a magnetic field generator for scanning the ion beam in the horizontal direction at a high speed, which increases the cost of the apparatus. There is a problem. Further, since the ion beam needs to be swung before reaching the semiconductor wafer, there is a problem that the beam line becomes long and the device becomes bulky.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a single-wafer ion implantation apparatus capable of uniformly implanting ions into a semiconductor wafer in a state where the emission direction of an ion beam is fixed.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to an ion implantation apparatus for fixing a direction of emission of an ion beam and mechanically moving a semiconductor wafer horizontally and vertically while implanting ions into the semiconductor wafer. The wafer platen holding the semiconductor wafer is moved at a constant speed V in a vacuum vessel.
a swing mechanism for reciprocating in the horizontal direction at s, and a vertical drive mechanism for vertically moving the wafer platen in the vertical direction at the same speed Vu together with the swing mechanism.

The swing mechanism includes an arm provided through the wall of the vacuum vessel, and the arm has the wafer platen at one end inside the vacuum vessel.
The other end of the outer side of the vacuum vessel is connected to an output shaft of a reciprocating rotation motor so as to reciprocate.

The vertical drive mechanism includes a slide plate provided on the outside of the vacuum vessel so as to be vertically movable along a wall, and the slide plate has the arm provided on a wall of the vacuum vessel. In addition to supporting vertically movable integrally through the elongated hole, the motor is supported,
Moreover, a sealing sliding seal is provided between the slide plate and the wall of the vacuum vessel around the elongated hole.

An auxiliary arm which rotates together with the arm is fixed to the arm outside the vacuum vessel, and an area excluding a predetermined range on both sides of the reciprocating rotation range of the arm is fixed at the constant velocity Vs. The slide plate is provided with a buffer mechanism at a position where the auxiliary arm is reversed.

The shock absorbing mechanism may be constructed by providing a spring on the slide plate to absorb the collision force of the auxiliary arm, or the magnetic poles may be opposed to the collision portion between the slide plate and the auxiliary arm. It is constituted by a magnet provided so as to perform.

Further, when the distance from the rotation center of the arm to the center of the semiconductor wafer is R, the constant velocity V
It is preferable to control the vertical drive mechanism so that u is inversely proportional to the distance R.

Further, the wafer platen has an electrostatic clamp mechanism for holding the semiconductor wafer, and rotates the electrostatic clamp mechanism so that the incident angle of the ion beam can be changed by driving a motor. It is preferable to provide a rotation mechanism.

In addition, a circulation circuit for coolant of at least one of water and gas is provided in the inside of the wafer platen, and a coolant that extends from the outside of the vacuum vessel to the circulation circuit through the inside of the arm. Is preferably provided.

Further, the arm may have a plurality of holding portions for holding the wafer platen.

[0016]

In this ion implantation apparatus, while the ion beam is fixed, the semiconductor wafer is moved at a high speed in the horizontal direction (high-speed scan) by the swing mechanism, and at the same time, is moved at a low speed in the vertical direction (low-speed scan) by the vertical drive mechanism. Then, ions are implanted. The frequency of the high-speed scan in the horizontal direction is about 10 Hz at the maximum. On the other hand, the scanning speed in the vertical direction is about 100 mm / sec at the maximum, and speed control is performed in consideration of the distance R from the center of rotation of the arm to the center of the semiconductor wafer in order to ensure uniform injection.
When changing the ion implantation angle, fix the vertical scan at the upper or lower end of the vertical slow scan, and rotate the wafer platen around its diametric axis to change the angle with respect to the ion traveling direction. I do. In addition, step implantation, etc., in which implantation is performed with the same beam while changing the implantation angle, are also possible.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. This embodiment is a single-wafer-type ion implantation apparatus, in which the emission direction of an ion beam is fixed, and the semiconductor wafer 1 is mechanically moved in a vertical direction and a horizontal direction, so that ions are uniformly injected into the entire semiconductor wafer 1. It is characterized by being able to do it.

This ion implantation apparatus includes a swing mechanism for reciprocating the wafer platen 2 holding the semiconductor wafer 1 in the vacuum vessel 9 at a constant speed Vs in the lateral direction, and a mechanism for moving the wafer platen 2 to the swing mechanism. And a vertical drive mechanism for vertically moving at a constant speed Vu in the vertical direction.

The swing mechanism includes a hollow L-shaped arm 7 provided through the wall of the vacuum vessel 9. The arm 7 is composed of a hollow rotary shaft 71 extending in the horizontal direction, and a hollow rocking arm 72 attached to one end thereof, that is, an inner end of the vacuum vessel 9 so as to extend in the vertical direction. The swing arm 72 has a Y-shaped support portion 73 at the upper end, and the wafer platen 2 is provided on the support portion 73 so as to be rotatable about a shaft 74. A pulley (or sprocket) 16 is provided at the other end of the rotating shaft 71 extending outside the vacuum vessel 9, and is connected to an output shaft of a reciprocating rotation motor 19 via a belt (or chain) 17. .
The swing arm 72 rotates the rotating shaft 7 by reciprocating rotation of the motor 19.
A predetermined angle range around 1 (X′-Y ′ shown in FIG. 1)
Do the rocking movement inside.

The vertical drive mechanism includes a slide plate 10 provided outside the vacuum vessel 9 so as to be vertically movable along a wall. The slide plate 10 supports the arm 7 so as to be integrally movable up and down through a long hole 91 provided in the wall of the vacuum vessel 9, and a motor 18 by a bracket 18.
I support. A sealing sliding seal 20 is provided between the slide plate 10 and the wall of the vacuum container 9 around the elongated hole 91.

The slide plate 10 is vertically driven at a constant speed Vu by a combination of a ball screw 24 rotated by a drive motor 23 mounted on the upper portion of the vacuum vessel 9 and a nut 26 mounted on the slide plate 10. Movable. In particular, the constant velocity Vu is up to 100
In order to ensure ion implantation uniformity, when the distance from the center of rotation of the arm 7 to the center of the semiconductor wafer 1 is R, the constant velocity Vu is raised and lowered so as to be inversely proportional to the distance R. It is known that controlling the drive mechanism is preferred.

A cylindrical body 4 extending inside the vacuum vessel 9 is provided in a hole of the slide plate 10 through which the rotary shaft 71 passes, and an electromagnetic seal unit is provided between the rotary shaft 71 and the cylindrical body 4. 41 and bearings 42 on both sides thereof. In this way, the arm 7 is rotatably supported by the slide plate 10 while sealing the gap around the rotation shaft 71.

An auxiliary arm 75 that rotates together with the rotary shaft 71 is fixed to the arm 7 outside the vacuum vessel 9, that is, the rotary shaft 71. The swing arm 72 moves the area XY in the reciprocating rotation range at a predetermined angle of X′-Y ′ shown in FIG. 1 except for the predetermined acceleration / deceleration ranges XX ′ and YY ′ on both sides at a constant speed. Vs. A buffer mechanism is provided on the slide plate 10 at a position where the movement of the auxiliary arm 75 is reversed. Here, the buffer mechanism is constituted by a spring 22 attached to a spring support 25 attached to the slide plate 10. The spring 22 is provided at an angular position where the auxiliary arm 75 contacts when the center of the semiconductor wafer 1 reaches the position X ′, Y ′ in FIG. As a result, for example, when the arm 7 moves from the position indicated by the solid line in FIG. 1 to the angular position Y in FIG. 1 by the forward rotation of the motor 19 at a constant speed Vs, the auxiliary arm 75 collides with the spring 22 at the angular position Y ′, At the same time as the motor 1 is reversed by the repulsive force of the spring 22,
9 reversely reaches the constant velocity Vs again at the angular position of Y 'and moves toward the solid line position.

Such a shock absorbing mechanism is configured such that permanent magnets are attached to positions where the auxiliary arm 75 and the spring support 25 are opposed to each other, and the magnetic poles are opposed to each other to utilize a repulsive force. good.

The wafer platen 2 holds the semiconductor wafer 1 by a well-known electrostatic clamping mechanism (for example, USP 543).
No. 6,780 or US Pat. No. 5,444,597). In order to improve the uniformity of ion implantation, a platen drive motor 3 is mounted in a case 27 at the rear of the wafer platen 2 and can rotate the semiconductor wafer 1 together with an electrostatic clamping mechanism in the direction indicated by the arrow in FIG. I have to. Further, as described above, the wafer platen 2
A ball screw mechanism is assembled to rotate the shaft around the shaft 74. The ball screw mechanism includes a platen tilt motor 12 attached to the arm 7, a ball screw 28, a platen tilt motor 12 and a ball screw 2
8 and a nut 29 attached to the cover 27. In this way, the wafer platen 2 is
The angle of incidence of the ion beam can be made variable by rotating about the axis 74 by the rotation of.

Although not shown, a cooling water and gas circulation circuit is provided in the case 27 of the wafer platen 2. The hollow space of the arm 7 is used to circulate water and gas in the circulation circuit. That is, the hollow portion and the swing arm 7
A pipe 14 for cooling water and a pipe 15 for cooling gas are inserted through the hollow portion 2 and are connected to a cooling water and cooling gas circulation circuit in the case 27 through a flexible hose through a support portion 73. The hollow space of the arm 7 is also used to pass a cable 13 for supplying power to the platen drive motor 3 and the platen tilt motor 12. Since the cooling water pipe, the cooling gas pipe and the cable in the arm 7 rotate or swing together with the rotating shaft 71 and the swing arm 72, the cooling water pipe, the cooling gas pipe and the cable came out of the rotating shaft 71. It is connected to a cooling water source, a cooling gas source, and a power supply side at a location through a flexible type pipe.

As described above, in order to make the ion implantation performed through the window 92 of the vacuum vessel 9 shown in FIG. 1 uniform, the movement of the semiconductor wafer 1 in the section X to Y shown in FIG. The speed is fixed, and sections X to X 'and Y to
Y ′ is an acceleration / deceleration section. Sections X to X 'and Y to Y
Acceleration and deceleration in ′ are assisted by a spring 22 attached to the slide plate 10 as shown in FIG. The slide plate 1 shown in FIG.
A low-speed movement is performed by the vertical movement of 0. The rotation of the wafer platen 2 by the platen drive motor 3 and the rotation of the wafer platen 2 about the rotation support shaft 74 by the platen tilt motor 12 allow the semiconductor wafer 1 to be arbitrarily moved with respect to the ion beam line. Can be given.

In this ion implantation apparatus, while the ion beam is fixed, the semiconductor wafer 1 is moved at a high speed in the horizontal direction (high-speed scan) by the swing mechanism, and at the same time, is moved at a low speed in the vertical direction (low-speed scan) by the vertical drive mechanism. And implant ions. The frequency of the high-speed scan in the horizontal direction is about 10 Hz at the maximum. On the other hand, the scanning speed in the vertical direction is about 100 mm / sec at the maximum, and speed control is performed in consideration of the distance R from the center of rotation of the arm 7 to the center of the semiconductor wafer 1 in order to ensure uniform injection. When changing the ion implantation angle, the slide plate 10 is fixed at the upper end or the lower end of the vertical low-speed scan, and the angle with respect to the ion traveling direction is changed by rotating the wafer platen 2.

FIG. 5 shows another embodiment of the present invention, in which two wafer platens 2 are provided to improve the productivity. For this purpose, the swing arm 72 has a support 73
Are provided. The rotation mechanism and cooling structure of the wafer platen 2 may be exactly the same as in the above-described embodiment, but the width of the vacuum container 9 needs to be widened.

The present method can be applied to electron, atom, neutron, molecule injection and the like in addition to ion implantation.

[0031]

The ion implantation apparatus according to the present invention has the following effects.

1. Since the ion beam can be fixed, there is no need for an electrostatic or magnet type mechanism for scanning the ion beam, and the beam line can be shortened, so that the length of the implanter can be shortened and the ion beam scanning mechanism is eliminated. Thus, the cost of the apparatus can be reduced.

2. The high-energy ion implanter and the high-current ion implanter have heretofore been of a batch type in which a plurality of ions are simultaneously implanted. An injection device can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of an ion implantation apparatus according to the present invention.

FIG. 2 is a side sectional view of a main part of the ion implantation apparatus according to the present invention.

FIG. 3 is a view of the vertical drive mechanism shown in FIG. 2 as viewed from the back.

FIG. 4 is a view of the wafer platen shown in FIG. 2 and components around the wafer platen viewed from the direction of arrow A in FIG. 2;

FIG. 5 is a front view of a main part of an ion implantation apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 2 Wafer platen 3 Platen drive motor 4 Cylindrical body 7 Arm 9 Vacuum container 10 Slide plate 11 Coupling 12 Platen tilt motor 13 Cable 14 Pipe for cooling water 15 Pipe for cooling gas 16 Pulley 17 Belt 19 Motor Reference Signs List 20 sliding seal 22 spring 23 drive motor 24, 28 ball screw 26, 29 nut 71 rotating shaft 72 swing arm

Claims (10)

[Claims] An ion implantation apparatus for implanting ions into a semiconductor wafer while mechanically moving the semiconductor wafer in a horizontal direction and a vertical direction while fixing a direction in which an ion beam is emitted. A swing mechanism for reciprocating the wafer platen in the vacuum direction at the same speed Vs in the vacuum vessel, and a vertical drive mechanism for vertically moving the wafer platen vertically at the same speed Vu together with the swing mechanism. An ion implantation apparatus comprising: 2. The ion implantation apparatus according to claim 1, wherein the swinging mechanism includes an arm provided through a wall of the vacuum vessel, and the arm is provided at one end inside the vacuum vessel. An ion implantation apparatus comprising a wafer platen, wherein the other end of the outside of the vacuum vessel is connected to an output shaft of a reciprocating rotation motor so as to reciprocate. 3. The ion implantation apparatus according to claim 2, wherein the up-down driving mechanism includes a slide plate provided on the outside of the vacuum vessel so as to be vertically movable along a wall.
The slide plate supports the arm so as to be able to move up and down integrally through a long hole provided in the wall of the vacuum vessel, supports the motor, and furthermore, supports the motor around the long hole. An ion implanter, wherein a sealing sliding seal is provided between a wall and the slide plate. 4. The ion implantation apparatus according to claim 3, wherein an auxiliary arm that rotates together with the arm is fixed to the arm outside the vacuum vessel, and both sides of the reciprocating rotation range of the arm. An ion implantation apparatus wherein an area excluding a predetermined range is moved at the constant velocity Vs, and a buffer mechanism is provided on the slide plate at a position where the auxiliary arm is reversed. 5. The ion implantation apparatus according to claim 4, wherein the buffering mechanism is provided by providing a spring for absorbing a collision force of the auxiliary arm on the slide plate. 6. The ion implantation apparatus according to claim 4, wherein the buffer mechanism is constituted by a magnet provided at a collision portion between the slide plate and the auxiliary arm such that the magnetic poles thereof face each other. An ion implanter characterized by the following. 7. The ion implantation apparatus according to claim 5, wherein when the distance from the rotation center of the arm to the center of the semiconductor wafer is R, the constant velocity Vu is inversely proportional to the distance R. An ion implantation apparatus, wherein the vertical drive mechanism is controlled. 8. The ion implantation apparatus according to claim 7, wherein the wafer platen has an electrostatic clamp mechanism for holding the semiconductor wafer, and the electrostatic clamp mechanism is driven by a motor to receive the ion beam. An ion implantation apparatus comprising: a rotation mechanism for rotating the angle so that the angle is variable. 9. The ion implantation apparatus according to claim 8, wherein a circulation circuit for coolant of at least one of water and gas is provided inside the wafer platen, and the arm also has a circulation circuit therethrough. An ion implantation apparatus, wherein a circulation circuit for a coolant that extends from the outside to the circulation circuit is provided. 10. The ion implantation apparatus according to claim 9, wherein said arm has a plurality of holding portions for holding said wafer platen.