JPH0448543A - Ion implanter for semiconductor board - Google Patents

Abstract

PURPOSE:To adjust the impurity concentration constant at the center section and periphery section of a semiconductor board by scanning an ion beam horizontally and vertically, and modulating the ion beam to change the shape of the ion beam according to the scanning position. CONSTITUTION:Horizontal deflecting plates 1 and vertical deflecting plates 2 scanning an ion beam horizontally and vertically are installed on the optical axis of the ion beam, and electrostatic quadruple lenses 3, 4 are installed at the rear position on a semiconductor board 6 side from the deflecting plates 1, 2. When an ion beam 5 with plus charges is scanned, the ion beam 5 is moved nearer to the electrode with a plus potential of the electrostatic quadruple lenses 3, 4 as it is moved apart from the position where the ion beam 5 is not scanned, and the ion beam 5 is squeezed horizontally and vertically respectively by the repulsion between plus charges.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor manufacturing device, and particularly to an ion implantation device having a function of controlling the shape of an ion beam according to the deflection position of the ion beam on a semiconductor substrate. It is something.

[Conventional technology]

When implanting impurities into a semiconductor substrate, conventional semiconductor substrate ion implantation equipment scans an ion beam horizontally and vertically for each semiconductor substrate to uniformly implant impurities into the semiconductor substrate. It was structured like this. In addition, the electrostatic quadrupole lens built into conventional semiconductor substrate ion implantation equipment is located in front of the deflection plate that scans the ion beam in the horizontal and vertical directions, that is, in a position farther from the semiconductor substrate, and simply ionizes the ion implanter. Its only function was to narrow down the shape of the beam.

[Problem to be Solved by the Invention 1] In this conventional semiconductor substrate ion implantation apparatus, when ions are implanted into a semiconductor substrate by scanning the ion beam in the horizontal and vertical directions, the shape of the ion beam remains constant without changing. Therefore, as shown in FIG.
There is a difference in the density of the ion beams 5a and 5b on the surface of the semiconductor substrate between the ion beams 5a and 5b on the surface of the semiconductor substrate. Therefore, the impurity concentration in the central portion 6a of the semiconductor substrate 6 is high, and the impurity concentration in the peripheral portion 6b is high.
There is a problem in that as the impurity concentration becomes thinner, in-plane variations occur within the semiconductor substrate, making it impossible to construct a uniform semiconductor device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor substrate ion implantation apparatus that solves the conventional problems by making the shape of an ion beam changeable.

[Means for Solving the Problems] In order to achieve the above object, a semiconductor substrate ion implantation apparatus according to the present invention includes a deflection plate and an electrostatic quadrupole lens, selects desired ions, This is a semiconductor substrate ion implantation device that implants impurities into a semiconductor substrate by accelerating the ion beam using an electric field and electrostatically scanning the ion beam.The deflection plate is used to scan the ion beam in a desired direction. The electrostatic quadrupole lens is disposed at a rear position on the semiconductor substrate side from the deflection plate, and modulates the ion beam to change the shape of the ion beam.

1) The semiconductor substrate ion implantation apparatus of the present invention scans an ion beam in the horizontal and vertical directions and modulates the ion beam to change the shape of the ion beam according to the scanning position. This is to adjust the impurity concentration at a constant level between the central part and the peripheral part.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) 1 to 3 are diagrams showing a first embodiment of the present invention.

In the figure, the device of the invention selects the desired ions,
The ion beam is accelerated by an electric field and electrostatically scanned to implant impurities into the semiconductor substrate. Deflection plate 1 and vertical deflection plate 2
Further, static 1!quadrupole lenses 3 and 4 are installed at the rear position on the semiconductor substrate 6 side from the deflection plate 1.2.

The electrostatic quadrupole lens 3 narrows down the shape of the ion beam in the horizontal direction, and the electrostatic quadrupole lens 4 narrows down the shape of the ion beam in the vertical direction. As shown in FIG. 3, the electrostatic quadrupole lens 3 includes a pair of static 1t quadrupole lenses facing left and right on the optical axis of the ion beam, connected to a positive voltage source 7, and a pair of vertically facing electrostatic 4
A heavy pole lens is connected to a negative voltage source 8. On the other hand, in the static t-quadrupole lens 4, a pair of electrostatic quadrupole lenses facing left and right on the optical axis of the ion beam is connected to a negative voltage source 8.
A pair of electrostatic quadrupole lenses facing each other vertically is connected to a positive voltage source 7.

FIG. 2 shows the beam line section of the semiconductor substrate ion implantation apparatus when the ion beam 5 having a positive charge is implanted into the semiconductor substrate 6 without being scanned. As shown in FIG. 3, when the ion beam 5 with a positive charge is scanned, the farther the ion beam 5 is from the position when it is not scanned, the more the positive charge of the electrostatic quadrupole lenses 3 and 4 increases. The ion beams 5 approach the heavy poles that have a potential, and due to the repulsion between the positive charges, the ion beams 5 move horizontally.

Narrowed down vertically.

(Example 2) 4 to 6 are diagrams showing a second embodiment of the present invention.

Figure 4 shows a horizontal deflection plate 1, a vertical deflection plate 2, an electrostatic quadrupole lens 3 for narrowing down the shape of the ion beam in the horizontal direction, and an electrostatic quadrupole lens 3 for narrowing down the shape of the ion beam in the vertical direction. This figure shows the arrangement of the heavy pole lens 4. FIG. 5 shows the case where the ion beam 5 having a positive charge is implanted into the semiconductor substrate 6 without being scanned. FIG. 6 shows a method of electrically connecting the electrostatic quadrupole lens 3.4. In this embodiment, the configuration is such that immediately after scanning the ion beam in the horizontal direction and the vertical direction, the ion beam is focused by the static quadrupole lenses 3 and 4.

In the embodiments shown in FIGS. 1 to 6 described above, the scanning method of the ion beam 5 in the horizontal direction and the vertical direction is not limited to any type. Furthermore, the shapes of the horizontal deflection plate 1, the vertical deflection plate 2, and the electrostatic quadrupole lenses 3 and 4 are not limited to those shown in the drawings. Quadrupole lens 3
, 4, a positive voltage source 7. The voltage of the negative voltage source 8 may be constant, or the voltage applied may be changed in synchronization with the horizontal and vertical scanning of the ion beam 5.

[Effects of the Invention] As explained above, the semiconductor substrate ion implantation apparatus of the present invention emits an electrostatic charge at a position behind the deflection plate that scans the ion beam in the horizontal and vertical directions, that is, on the side closer to the semiconductor substrate.
By installing a heavy pole lens, the shape of the ion beam can be changed depending on the scanning position, making the impurity concentration constant between the center and the periphery of the semiconductor substrate, and improving in-plane uniformity within the semiconductor substrate. This has the effect that a uniform semiconductor device can be constructed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a beam line section of a semiconductor substrate ion implantation apparatus in Example 1 of the present invention, and FIG. 2 is a schematic diagram showing the case in which the ion beam is implanted into a semiconductor substrate without being scanned in FIG. 1. 3 is a schematic diagram showing the electrical connection state of the electrostatic quadrupole lens in FIG. 1, and FIG. 4 is a schematic diagram showing the beam line section of the semiconductor substrate ion implantation apparatus in Example 2 of the present invention. 5 is a schematic diagram showing the case in which the ion beam is implanted into a semiconductor substrate without being scanned in FIG. 4,
Fig. 6 is a schematic diagram showing the electrical connection state of the electrostatic quadrupole lens in Fig. 4, and Fig. 7 is a schematic diagram showing the electrical connection state of the electrostatic quadrupole lens in Fig. 4. FIG. 2 is a conceptual diagram showing a case of injection. 1... Horizontal direction deflection plate 2... Vertical direction deflection plate 3... Electrostatic quadrupole lens 4 for focusing in the horizontal direction
...Electrostatic quadrupole lens 5 for narrowing down in the vertical direction.
...Ion beam 7...Plus voltage source 8...
・Negative voltage source

Claims (1)

[Claims] (1) It has a deflection plate and an electrostatic quadrupole lens, selects desired ions, accelerates them using an electric field, electrostatically scans the ion beam, and implants impurities into the semiconductor substrate. A semiconductor substrate ion implantation apparatus for performing semiconductor substrate ion implantation, wherein the deflection plate scans the ion beam in a desired direction, and the electrostatic quadrupole lens is disposed at a rear position on the semiconductor substrate side from the deflection plate. 1. A semiconductor substrate ion implantation apparatus, characterized in that the ion implantation apparatus modulates an ion beam to change the shape of the ion beam.