JPS6240369A - Ion implantation device - Google Patents

Abstract

PURPOSE:To permit the precise control of the quantity of the impurity to be implanted by insulating a shielding plate from an ion implantation device body, grounding the same separate therefrom and measuring the quantity of the secondary electrons generated when neutralized particles collide against the shielding plate with a grounding circuit. CONSTITUTION:Ion beams are led out by a lead-out electrode 2 from an ion source 1 which generates source plasma. The necessary ion beam is selected by a mass spectrograph 3. The ion beam is then accelerated by an acceleration tube 4 and is focused by an electrostatic focusing lens 5. The neutralized particles are advanced strightforward via a vertical scanning plate 6 and a horizontal scanning plate 7 by a deflecting plate 8 so as to collide against the shielding plate 9. The shielding plate 9 is insulated from the ion implantation device body and is separately grounded. An instrument 10 to measure the quantity (i) of the secondary electron to be generated by the collision of the neutralized particles is connected to the grounding circuit 9a. The quantity of the neutralized particles generated in the route up to the plate 8 is thereby made measurable and the quantity of the neutralized particles generated after the plate 8 and to be implanted to the sample S is precisely estimated, by which the quantity of the impurity to be implanted is exactly controlled.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an ion implantation device used for manufacturing semiconductor devices, etc., and more specifically, the present invention relates to an ion implantation device that is used for manufacturing semiconductor devices, etc., and more specifically, the present invention relates to an ion implantation device that is used to manufacture semiconductor devices, etc. The present invention relates to an improved ion implanter that can be precisely controlled.

[Technical Background of the Invention] Ion implantation, a major technology, is widely used as a technology for introducing impurities into semiconductors in the manufacture of semiconductor devices, and in the current semiconductor device manufacturing process, so-called medium current ion implantation equipment is the most popular. ing.

FIG. 2 is a schematic diagram showing the structure of a medium current ion implantation device that is currently widely used. In the same figure, 1
is an ion source that generates source plasma, 2 is an extraction electrode for extracting an ion beam from the ion source, 3 is a quality analyzer that selects only the necessary ion beam from the extracted ion beam, and 4 is an ion analyzer that selects the selected ions. An acceleration tube for accelerating the beam, 5 an electrostatic focusing lens for focusing the accelerated ion beam, 6 a vertical scanning plate for vertically scanning the focused ion beam, and 7 a horizontal scanning plate for scanning the focused ion beam. a horizontal scanning plate 8 for scanning the ion beam in the direction of neutralization by deflecting the ion beam by, for example, 7 degrees toward the surface of the sample (for example, a semiconductor wafer) S; particles (molecules and atoms)
A deflection plate 9 is a shielding plate with which the neutralized particles separated from the ion beam collide.

The shielding plate 9 is made of a material such as graphite or A1, which does not produce particles that have a negative impact on the system due to the collision of neutralized particles than the material of the beam tube 11. It is electrically grounded through the main body of the ion implantation device by pasting it on the tube 11 or the like. Further, the entire system is maintained at high vacuum by a cryopump and an oil diffusion pump (not shown). Note that since each of these elements is already well known, detailed explanation thereof will be omitted.

[Problems with the previous day's technology] When implanting impurity ions into a semiconductor wafer or the like using a known medium current ion implantation device such as the one described above, conventionally, the amount of charge of the ions entering the sample chamber 12 in which the sample S is placed is However, this method of controlling the implanted impurity R has a problem in that it is not possible to accurately control the amount of the implanted impurity.

- That is, in the ion implantation apparatus as described above, although the neutralized particles generated on the path from the acceleration tube 4 to the deflection plate 8 are separated, the neutralized particles generated on the path from the deflection plate 8 to the sample S are separated. This is because the impurity particles are injected into the sample S together with the ions, so even if the amount of charge of the ions in the sample chamber 12 is measured, the measured value will not match the actual amount of impurities implanted.

By the way, the cause of fluctuations in the degree of vacuum in the system is J:
Therefore, 10 ions of ions are lost on the path from the deflection plate 8 to the sample S.
It is not uncommon for % to become neutral. In addition, none of the conventional ion implanters is equipped with a means for measuring the neutralized particles m, whether up to the deflection plate or after the deflection plate.

Therefore, since the known ion implantation apparatus described above cannot control the implantation amount accurately, it has been impossible to achieve high precision in the formation of various layers and films in the manufacture of semiconductor devices.

[Object of the Invention] An object of the present invention is to provide an improved ion implantation device that solves the problems in the known ion implantation devices and is capable of performing ion implantation with higher precision than conventional devices. It is.

[Principal Part of the Invention The feature of the ion implanter improved by this invention is that the secondary electron generating can corresponding to the neutralized particles generated in the path from the quality analyzer to the deflection plate is electrically activated. By measuring, it is possible to estimate the amount of neutralized particles generated in the next path from the deflection plate to the sample. Therefore, in addition to measuring the amount of ions implanted into the sample, it is now possible to accurately estimate the amount of neutralized particles of neutral atoms and molecules, which makes it possible to know the exact amount of impurity implanted into the sample. More specifically, in the configuration of the ion implantation apparatus of the present invention, the shielding plate 9 is first insulated from the ion implantation apparatus main body and grounded separately, and secondary electron emission in the shielding plate 9 (this is caused by the secondary electron emission from the shielding plate 9
An ammeter device (or circuit) for electrically measuring the phenomenon in which secondary electrons are generated from the surface of the shielding plate 9 due to neutralized particles colliding with the shielding plate 9 is connected to the ground circuit of the shielding plate 9. The present invention is characterized in that it is possible to measure the amount of impurity injection more accurately by electrically measuring the damage caused by neutralized particles occurring in the path from the quality analyzer to the deflection plate.

[Embodiments of the Invention] FIG. 1 is a schematic diagram for explaining the structure of the main parts of the ion implantation device of the present invention and the operation of the device. In the same figure, the same symbols as in FIG. The parts shown are the same as those of a conventional ion implanter.

The ion implantation apparatus of the present invention shown in FIG. 1 is characterized in that a secondary electronic valve status measuring device 10 is connected to the ground circuit 9a of the shielding plate 9.

The shielding plate 9 generally has a structure in which a metal plate is layered. Therefore, when molecules, atoms, or electron particles collide with the shielding plate 9, secondary electron emission occurs, and as a result, the grounding circuit 9 is connected to the ground. A weak current i is generated. In the present invention, a secondary electron generator measuring device 10 for detecting and measuring this weak current is connected to the grounding circuit 9a of the shielding plate 9, and further, the measuring device 10 is electrically connected to the control device of the ion implantation device. . Therefore, it is possible to electrically measure the base of the neutralized particles generated on the path up to the deflection plate, and as a result, the amount of neutralized particles generated after the deflection plate and injected into the sample S can be precisely determined. In addition to being able to estimate the amount, the amount of untrapped materials to be implanted can be accurately controlled by stopping or correcting ion implantation using the control device of the ion implantation apparatus.

In addition, in FIG. 1, the arrow N indicated by d3 indicates the flow of neutralized particles, and the arrow J indicated by the arrow J indicates the flow of ions implanted into the sample S. Also,
e- represents secondary electrons generated in the shielding plate 9.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, an improved ion implantation device that can perform ion implantation more accurately than conventional ion implantation devices can be obtained. As a result, in the manufacture of semiconductor devices, elements can be formed with higher precision.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram schematically showing the main parts of the invention in the device of the present invention and the flow of particles such as ions in the device of the present invention, and FIG. 2 is a schematic diagram of a conventional medium current ion implantation device. . 1... Ion source, 2... Extraction electrode, 3...
Mass spectrometer, 4... Accelerating coil, 5... Electrostatic focusing lens, 6... Vertical scanning plate, 7... Horizontal scanning plate, 8... Deflection plate, 9... Shielding plate, 9a...
・Grounding circuit, 10...Secondary electron generation amount measuring device, 1
1...Beam tube, 12...Sample chamber.

Claims (1)

[Claims] 1. An extraction electrode that extracts ions generated in the ion source;
A mass spectrometry system that selects the necessary ions from among the extracted ions, an acceleration system that accelerates the selected ions, a focusing system that focuses the accelerated ions, and a scanning system that controls the focused ion beam to scan the sample surface. , a deflection system that separates neutralized particles from within the ion beam and deflects the ion beam toward a sample surface; a shielding plate with which the neutralized particles separated from the ion beam collide; and the deflected ions. In an ion implanter equipped with a sample chamber in which a beam is injected into a sample, the shield plate is insulated from the ion implanter body and separately grounded, and when the neutralized particles collide with the shield plate, An ion implantation apparatus characterized in that a secondary electron generation measuring device for measuring the amount of secondary electrons generated from the shielding plate is provided in a grounding circuit of the shielding plate.