JPS6276147A - Ion implanting apparatus - Google Patents

Abstract

PURPOSE:To much improve the efficiency of ion implanting work and enhance the rate of operation of an ion implanting apparatus, by providing a wafer holder with a wafer support angle adjustment means for optionally adjusting the angle of a wafer to an ion beam irradiated upon the face of the wafer. CONSTITUTION:A wafer holder 23 is made of a U-shaped frame. A wafer support angle adjustment means 24 is attached between the mutually-facing top and bottom plates 23a, 23b of the wafer holder 23. When the angle of incidence of an ion beam 6 is to be changed, a wafer 3 is fitted on a rotary plate 28 and the angle of the wafer to the ion beam is then altered by the rotation of a rotary frame 26 and the rotary plate 28 depending on the portion of the wafer upon which the ion beam is to be irradiated. The wafer 3 is thus turned upward, downward, rightward and leftward while the ion beam 6 is irradiated upon the wafer, so that the implantation of ions into one wall surface (m) of the groove 16 of the wafer 3 and that of ions into the other wall surface (n) thereof, for example, can be performed continuously to each other. This results in much improving the efficiency of ion implanting work.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus for implanting impurity ions into a semiconductor wafer.

Diffusion of impurities such as phosphorus and boron into semiconductor wafers
Usually, this is done using a gas diffusion method, but this gas diffusion method requires heat treatment at high temperatures, which poses problems in terms of workability, concentration distribution, energy consumption, etc. Therefore, recently, an ion implantation method in which an impurity/ion is implanted into a semiconductor wafer has been attracting attention and being praised as an impurity diffusion method that does not have the above-mentioned problems. This ion implantation method includes a low current or medium current method in which a low or medium current ion beam is deflected and scanned at a fixed angle over the semiconductor wafer, and a high current ion beam is deflected and scanned at a fixed angle with the ion beam. There is a high ci flow method that irradiates the semiconductor wafer along the plane of the ion implanter.
The latter type of ion implantation apparatus will be explained below with reference to FIG.

In the low-current or medium-current ion implantation device (A) shown in Fig. 6, (1) is a box-shaped main body, and (2) is a main body (1
), and (3) is one semiconductor wafer (hereinafter referred to as a wafer) supported on the front surface of the wafer holder (2). Inside the main body (1), (4) is an ion source that generates ions containing target ions, (5) is an extraction electrode that extracts the ion beam (6) from the ion source (4), and (7) is an extraction electrode. (
An ion separator that applies a magnetic field to the ion beam (6) extracted in 5) to separate target ions and unnecessary ions;
8) is a slit through which the ion beam (6) made of only the target ions from the ion portion 11B (7) passes, (9) is an acceleration system that accelerates the ion beam (6) that has passed through the slit (8), (10) is a focusing system that focuses the ion beam (6) accelerated by the acceleration system (9) so that it has a convergence point on the wafer (3) in front, and (11) focuses the ion beam (6) on the wafer (3) in front of it. This is a deflection system that scans in the X direction and Y direction.

The ion beam (6) irradiated from the main body (1) is a low current or medium current ion beam, and this ion beam (6) is irradiated at a predetermined incident angle to the wafer (3) in front of the wafer (3). 3) Implant impurity ions into the wafer (3) by scanning the entire surface.

In the high-current ion implantation apparatus (B) of FIGS. 7 and 8, (12) is a disk-shaped wafer holder, and a plurality of wafers ('3) (3)- are arranged at equal intervals around the front surface of the wafer holder (12). Supported by (13) is a drive mechanism that rotates and moves the wafer holder (12) up and down. (14) is a main body that is placed at a fixed position in front of the wafer holder (12) and irradiates a high-current ion beam (15) toward the wafer holder (12) from a fixed direction. It is the same as the main body (1) of the ion implanter (A) shown in the figure except for the deflection system (11).

In the case of this ion implanter (B), the wafer holder (1
Each wafer (3) (
3)- are sequentially sent to the incident position of the ion beam (15), and each wafer (3) (3).- is sequentially and ion-implanted several times.

In addition, the incident angle of the ion beam to the wafer in such a low current, medium current, or high current method is such that when the ion beam is parallel to the channeling axis of the crystal of the constituent atoms of the wafer, the ion beam is Deeper than necessary (
In order to prevent this channeling phenomenon, the ion beam is set to be incident at an angle of about 7° with respect to the normal to the wafer.

By the way, the internal structure of wafers into which ions are implanted using an ion implanter varies, but some wafers may need to be set in the same ion implanter multiple times for ion implantation.

For example, as shown in FIG. 9, in a wafer (3a) in which grooves (16) are formed in a grid pattern along the device dividing lines on the surface, electric field concentration at the edge portion (17) of m (16) is prevented. Impurity ions may be implanted into the opposing wall surface (m) (n>) of the groove (16) for the purpose of ), first irradiate the ion beam (19) from a fixed direction toward one wall surface (m) of i (IG), then remove the wafer (3a) from the wafer boulder, and remove the wafer (3a) from the wafer boulder.
) is rotated 180° and placed on the wafer holder again, and a 1° on-beam (
19), the ion implantation into the wafer (3a) required a lot of man-hours and effort, and the workability was extremely poor.

Furthermore, in the case of the wafer (3b) shown in FIG. 10, the workability of ion implantation was extremely poor. That is,
First, a first impurity region (21) with a low impurity concentration is formed by ion implantation along the protrusions (20) partially formed on the surface of this wafer (3b), and then the first impurity region (21) is formed by ion implantation. 21) Impure v! J Second impurity region with high degree of fire (
22) is formed by ion implantation, and both impurity regions (21
) and (22) to prevent electric field concentration between them and improve reliability. In this case, the first impurity region (
21) is formed by irradiating the ion beam (19) from the direction facing the side surface of the protrusion (20), and then the wafer (3b) is rotated 180° and the ion beam (19) is
7 and the protrusion (20) of the first waste area (21)
) is irradiated with the ion beam (19) to form a second impurity region (22). Therefore, in this wafer (3b) as well, the -ion implantation operation required the labor and effort of removing the wafer from the wafer holder at least once and setting it again.

Therefore, the present invention provides a wafer (3a) as described above.
(3b), it is an object of the present invention to provide an apparatus for efficiently implanting ions therein.

A technical means for achieving the above object of the present invention is that the wafer holder in the ion implantation device is irradiated from the front.
(c) A wafer support angle adjustment means is provided to arbitrarily and variably adjust the angle of the wafer with respect to the on-beam.

According to the above-mentioned technical means, the angle of the wafer supported by the wafer holder with respect to the ion beam from the front can be changed arbitrarily while being supported by the wafer holder. However, it can be done with less man-hours and with better workability.

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2, and a second embodiment will be described with reference to FIGS. 3 to 5.

The first embodiment shown in FIGS. 1 and 2 is one in which the present invention is applied to a low-current or medium-current type ion implantation device. Wafer (
3), the following wafer support angle adjustment means (24) is attached to the wafer holder (23).

The wafer holder (23) is a U-shaped frame body, and a wafer support angle adjusting means (24) is assembled between its upper and lower end plates (23a) and (23b) that face each other. The tool support angle adjustment means (24) adjusts the upper and lower ends of the wafer holder (23).
(23a)<23b), and is inserted between the upper and lower end plates (23a)
) (23b) with support shafts (25) (25), and is rotatably supported in the left and right direction about the support shafts (25) (25); It is inserted into the rotating frame (26) and the side plate (
26a) (26b) has a rectangular plate-shaped rotary plate (28) which is connected to the spindle (27) (27) and is rotatably supported up and down about the spindle (27) (27) as a fulcrum. It has a gimbal structure, and on the front of the rotating plate (28),
A plurality of claw pieces (29) that removably hold one wafer (3) at the center of the front surface of the rotary plate (28) (29)-
is placed. The rotating frame (26) and rotating plate (28) are rotated independently, for example, by two independent rotational drive control mechanisms (30) and (31) disposed outside.

The wafer holder (23) is set in the wafer holder (23).
3) is one that undergoes ion implantation only with the ion beam (6) at a constant angle of incidence, the wafer holder (23)
The wafer (3
) is mounted and the wafer (3) is held at a constant angle toward the main body (1), and the ion beam (6
) may be scanned onto the wafer (3). Also, the wafer (3) may be M9rA or the wafer (3a) in Figure 10.
If it is necessary to change the angle of incidence of the ion beam (6) as in (3b), the wafer (3) is placed on the rotating plate (
28), the ion beam (
6) The angle of the wafer (3) with respect to the ion beam (6) is varied by the rotation of the rotating frame (26) and rotating plate (28), depending on the location where the ion beam (6) is emitted. In this way, while irradiating the wafer (3) with the ion beam (6), the wafer (3) is irradiated with the ion beam (6).
For example, in the FF19 rooster wafer (3a), rotate the -wall surface (m) of the groove (16) vertically and horizontally.
) and the other wall surface (n) can be performed continuously, greatly improving work efficiency.

Next, a second embodiment shown in FIGS. 3 to 5 will be described. This second embodiment is a high current type ion implantation apparatus (
B) to which the present invention is applied; in this case, the main body (14
) A plurality of independent wafer support angle adjusting means (33) of the same structure are arranged at equal intervals around the periphery of a disc-shaped wafer holder (32) that rotates and moves up and down at a fixed position in front of the (33).
It is characterized by adding -・.

One wafer support angle adjusting means (33) is attached to a rectangular opening (34) at the periphery of the wafer holder (32), and there are support shafts (35) on both sides of the opening (34).
A rectangular rotary plate (36) connected to the rotary plate (35) and rotatably mounted in the radial direction of the wafer holder about the supporting shaft (35) (35), and a rotating plate (36) formed in the center of the The disc (38) is housed in the round hole (37) and is fixed to the back side of the rotary plate (36) via a mounting bracket (39), and the disc (38) is connected to the rotary plate (36). A disk rotation drive unit (40) is supported in parallel and rotates the disk (38) around its center point, and a disk rotation drive unit (40) is arranged on the back side of the wafer holder (32) and rotates the rotation plate (36) It has a rotary plate rotation drive unit (41) that rotates. 1 on the front of the disk (38)
A plurality of claw pieces (
42) <42)- is installed.

In the case of this second embodiment, the wafer holder (32) is rotated and moved up and down, and each wafer support angle adjusting means (33) is rotated and moved up and down.
) (33)・-Wafer (3) (3)
- to the front of the main body (14), and the ion beam (15)
The angle of the wafer (3) to which the ion beam (15) is irradiated with respect to the ion beam (15), the rotation plate (36) and the circle ffi are determined as necessary.
Change by independent rotation of <38>. In this way, the wafer (3) can be changed to the wafer (3) shown in FIGS. 9 and 10.
a) Even in (3b), the ion implantation can be performed continuously and with good workability.

It should be noted that the present invention is not limited to the above-mentioned embodiment; for example, a device similar to the wafer support angle adjusting means of the above-mentioned first embodiment can be used in a high-current type ion implantation apparatus, It is also possible to use something similar to the wafer support angle adjustment means in a low current or medium current type ion implantation device.

According to the present invention, it is possible to easily perform multi-form ion implantation by irradiating the wafer with an ion beam at any incident angle while the wafer is supported on the wafer holder. The ion implantation work for a wafer, which conventionally required ion implantation to be carried out in several steps, can be done in one step, and the ion implantation workability can be greatly improved and the operating rate of the ion implantation apparatus can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view including a partial cross section of a main part showing an embodiment of an ion implantation apparatus according to the present invention, and FIG. 2 is a partial perspective view of the apparatus shown in FIG. FIG. 3 is a plan view of main parts showing another embodiment of the present invention, FIG. 4 is a partially enlarged perspective view of the device shown in FIG. 3, and FIG.
- It is a sectional view along the X-line. Figures 6 and 7 are schematic plan views showing the two sides of a conventional ion implanter, Figure 8 is a front view of the wafer holder in the equipment shown in Figure 7, and Figures 9 and 10 are diagrams of semiconductor wafers. Each is a partial sectional view. (3) - semiconductor wafer, (6) (15) - ion beam, (23) - wafer holder, (24) - wafer support angle adjustment means, (32) - wafer holder,
(33) - Wafer support angle adjustment means.

Claims (1)

[Claims] (1) In a device that implants an ion beam from a fixed direction into a semiconductor wafer in a fixed position supported by a wafer holder, the angle of the semiconductor wafer with respect to the ion beam irradiated from the front to the wafer holder is arbitrarily variably adjusted. An ion implantation apparatus characterized by being equipped with a wafer support angle adjustment means.