JPS62115640A - Ion implanting apparatus - Google Patents

Abstract

PURPOSE:To facilitate efficient take-out of the optimal ions beam by making the position and the width of an analyzing slit variable and operatable from the outside. CONSTITUTION:Upon rotation of a screw shaft 10, movable boards 9 will move in the opposite directions thus the width of a lateral analysis slit section 13 can be varied freely. If the taking-out electrical field and the analyzing magnetic field are constant, the resolution will be inversely proportional to the larger value of the beam width and the analyzing slit width. While, since the mass number M of ions will vary in integer value, the resolution necessary for separating the ions having adjoining mass numbers will be proportional to 1/M. Consequently, when varying the width of the lateral analysis slit section 13 in accordance with the mass number of ions to be separated and increasing the allowable variation of the ion beam width, the quantity of said beam can be increased.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an ion implantation device.

(Prior Art) As is well known, in ion implanters, especially post-acceleration ion implanters, ions generated in an ion source are extracted using an extraction electric field, and then desired ion species are mass-analyzed using an analytical magnetic field. This is then accelerated using an accelerating electric field to provide the necessary energy.

In this case, in order to extract only the desired ion species,
It is common practice to provide an analysis slit between the analysis tube and the acceleration tube, that is, near the exit focal point of the analysis magnetic field, to prevent other ion species from mixing after analysis.

However, the installation position and slit width of conventional analysis slits of this type are fixed.

By the way, it is known that the resolution of ion species in this type of device is inversely proportional to the analysis slit width when the electric field for extraction and the magnetic field for analysis are the same and the beam width is small. Here, the required resolution for the mass number is proportional to 1/M because the mass number (which is referred to as M) usually changes by an integer value.

Therefore, for example, in the case of a boron ion, the mass number is 1
1, whereas the mass number of an arsenic ion is 75, so in the case of boron, the resolution may be about 7 times looser, and the slit width may be made wider accordingly. Nevertheless, in conventional analysis slits with a fixed slit width, the slit width must be set in accordance with severe conditions, that is, in the above-mentioned example, in accordance with arsenic. ``In this case, the amount of ion species with a small mass number passing through the slit decreases, and the amount of these ion species is wasted accordingly.

Further, as the parameters of the ion source change, the parameters of the ion beam incident on the analysis magnetic field also change, which also causes the focal point near the exit of the analysis magnetic field to move. If the position of the slit cannot follow this movement, the required ions will not be able to pass through the slit,
As a result, not only is there an unavoidable loss of ion quantity, but also the ion beam collides with the wall of the implanter, generating impurity ions.

There is a risk that this may enter the accelerator tube.

(Problems to be Solved by the Invention) This invention aims to efficiently extract an optimal ion beam according to the ion species to be extracted, as well as ion source parameters, extraction parameters, implantation parameters, etc. With the goal.

(Means for Solving the Problems) The present invention makes the position and width of the analysis slit variable, and by making this adjustable from the outside, the resolution and alignment of the ion beam can be adjusted by operating the analysis slit. It is characterized in that it is performed by.

(Example) An example of the present invention will be described with reference to the drawings. 1 is a mass spectrometer that analyzes desired ions from ions extracted from an ion source; 2 is an analysis slit device; and 3 is an acceleration tube that accelerates the ions that have passed through the analysis slit device 2. The analysis slit device 2 is arranged between the mass spectrometry tube 1 and the acceleration tube 3.

Although these structures are not particularly different from ordinary devices of this type, in the present invention, the above-mentioned analysis slit device 2 is made to have variable widths and positions of the slits. In FIG. 0, whose detailed configuration will be explained with reference to FIG. . This sliding movement of the support base 6 is performed by the rotation of the screw shaft 7. The screw shaft 7 is led out to the outside of the container (not shown), and its rotation is controlled by an external motor or the like.

A pair of movable plates 9 are slidably installed on the surface of the support base 6 along a rail 8 extending in a direction parallel to the rail 5. The south rotating plates 9 are configured to slide in opposite directions when the screw shafts 1o rotate in the same direction. Like the screw shaft 7, this screw shaft 10 is also led out to the outside of the container (not shown), and its rotation is controlled by an external motor or the like. However, since the position of the screw shaft 10 changes as the support base 6 moves, the motor that rotates the screw shaft 10 is also installed in a movable state according to this position change.

A lateral analysis slit piece 12 is installed at the tip of the movable plate 9 via a shielding plate 11, thereby forming a lateral analysis slit section 13. Therefore, by sliding the movable plate 9, the width of the horizontal analysis slit portion 13 can be changed arbitrarily.

Reference numeral 14 denotes a vertical analysis slit piece, which is configured in the shape of a horizontally long picture frame and is integrally attached to the support base 6. Even if the width of the horizontal analysis slit portion 13 is changed as described above, the vertical analysis slit piece 14 is always opposed to the changed width.

In the above configuration, when the screw shaft 10 is rotated, the movable plates 9 move in mutually opposite directions, and the width of the horizontal analysis slit section 13 can be arbitrarily changed by this movement. As described above, if the electric field for extraction 1 and the magnetic field for analysis are constant, the resolution is inversely proportional to the larger value of the width of the beam and the width of the analysis slit. Furthermore, since the mass number M of an ion varies by an integer value, the resolution required to separate ions of adjacent mass numbers among the ions is proportional to 1/M.

Therefore, by changing the width of the horizontal analysis slit section 13 in accordance with the mass number of the ions to be separated and increasing the allowable value for changing the ion beam width, the amount of the beam can be increased. It becomes like this.

Also ion source parameters, extraction parameters.

The activation of ions in the analytical magnetic field may change due to changes in the magnetic field, etc. or changes in the ions, and the beam is not always focused on the analytical slit at a fixed position. This prevents the maximum and best ion beam under the conditions from being directed to the target.

On the other hand, the support stand 6 is moved using the screw shaft 7, and the position of the horizontal analysis slit section 13 is moved left and right to find the optimum alignment corresponding to the desired ion beam parameters. That is, the horizontal analysis slit section 13
If the position is moved to match the focal position of the beam, there will be no loss in the amount of ions, and the generation of impurity ions due to collisions in other parts will be reduced.

Furthermore, by adjusting the position of the horizontal analysis slit section 13, it becomes possible to easily correct misalignments in the beam line assembly. Further, even when it is necessary to vary the width of the slit in order to generate a minute beam amount, this mechanism can be easily used as is by changing the slit width using the screw shaft 10.

(Effects of the Invention) As detailed above, according to the present invention, generated ions are not wasted during ion implantation, and the maximum and best ion beam is targeted under conditions that suit resolution and alignment. This has the effect of making it possible to inject into the body.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the main parts of this invention, and FIG. 2 is a plan view showing an embodiment of this invention.・Acceleration tube, 6・
...Support stand, 9...Movable plate, 12...Horizontal analysis slit piece, 13...Horizontal analysis slit part, 14...Vertical analysis piece, lift piece.

Claims (1)

[Claims] In an ion implanter including an analysis slit device provided between a mass spectrometer tube and an acceleration tube, the analysis slit device is configured such that the width and position of the analysis slit portion can be freely adjusted according to ion resolution and alignment. Ion implantation equipment.