JPH0499274A - Ion implantation device - Google Patents

Abstract

PURPOSE:To inhibit breakdown of a semiconductor device due to charge up by individually performing ion implantation to a plurality of semiconductor wafers and performing light irradiation and destaticizing charge on the surfaces of the wafers and cooling the semiconductor wafers. CONSTITUTION:An ion implantation device is provided with an ion implantation part, a mercury lamp 3 of a light irradiation part and a wafer cooling part 11. The ion implantation part individually performs ion implantation to a plurality of semiconductor wafers 10, 10 on the basis of a required sequence. The light irradiation part performs light irradiation to the semiconductor wafers 10, 10 and charge on the surfaces of these wafers is destaticized. The wafer cooling part 11 cools the semiconductor wafers 10, 10 irradiated with light. Thereby, the charge is removed which is accumulated on the surfaces of the wafers or to the electrodes formed on the surfaces thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion implantation apparatus used for manufacturing semiconductor devices, and particularly to a batch type ion implantation apparatus.

[Prior Art] In a conventional batch type ion implantation apparatus, as shown in FIG. Ru. At this time, in order to make the implanted ion concentration uniform throughout the wafer, the wafer disk 9 rotates at high speed around the wafer disk rotation axis 13, and the wafer disk rotation axis 13 reciprocates either vertically or horizontally. repeating the exercise. In some cases, the wafer disk 9 only rotates,
An accelerated ion beam is scanned vertically or horizontally. Such ion implanters are particularly common in high current or high energy ion implanters. Therefore, during ion implantation in semiconductor device manufacturing, high-density ion charges are not released from the semiconductor wafer surface and accumulate on the semiconductor wafer surface or surface insulating film, as well as the electrodes and mask material formed on top of it, and eventually the charges A charge-up phenomenon occurs in which the semiconductor device is destroyed. To suppress this phenomenon, during ion implantation,
A charge neutralization device 14 that irradiates the semiconductor wafer surface with electrons to neutralize positive charges accumulated on the semiconductor wafer surface may be used.

[Problems to be Solved by the Invention] In this conventional ion implantation apparatus, when performing high-current ion implantation in the manufacture of semiconductor devices, for example, the current density of ions implanted into the wafer is high. There have been problems in that the gate insulating film is destroyed due to the charge-up phenomenon of the electrode formed on the surface, the uniformity of implanted ions deteriorates on the wafer, and the semiconductor device is destroyed, such as destruction of the capacitor. In order to solve this kind of problem, it has been proposed in the past to add a charge neutralization device 14 using electrons into the device, but with this method, there are too many electrons on the semiconductor surface. On the contrary, the semiconductor device may be destroyed due to the electron charge-up phenomenon.Furthermore, the electrons from the charge neutralization device 14 may reach the part where the ion beam has not been implanted, resulting in the above-mentioned problem. There was a problem that the semiconductor device could be destroyed due to the electron charge-up phenomenon.

An object of the present invention is to provide an ion implantation device that solves the charge-up phenomenon during ion implantation.

[Means for Solving the Problems] In order to achieve the above object, an ion implantation apparatus according to the present invention includes an ion implantation section, a light irradiation section, and a wafer cooling section, the ion implantation apparatus comprising: The implantation section performs ion implantation into multiple semiconductor wafers individually based on a desired sequence, and the light irradiation section irradiates the semiconductor wafers with light to eliminate charges on the wafer surface. The cooling part is
It cools the semiconductor wafer that has been irradiated with light.

[Effect]

By performing ion implantation while irradiating light with energy higher than the potential MW of the insulating film formed on the surface of the semiconductor wafer, charges accumulated on the semiconductor surface can be released to the substrate side and surroundings. However, if only the ion-implanted area is irradiated with light, the charge may not be released sufficiently, or excess electrons from the charge neutralization device may cause charge-up at positions other than the ion-implanted area, resulting in ion implantation. By irradiating high-energy light at positions other than the wafer surface, charges accumulated on the wafer surface or electrodes formed on the surface are removed.

[Example] Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
It is a sectional view taken along the line AA' in the figure.

In the figure, 5 is the ion beam passage port of chamber l, and the ion beam that has been accelerated and scanned in the horizontal direction is
Pass through the ion beam passage port 5 and go 1o from the right direction in Figure 2.
It is injected into the wafer disk 9 and the semiconductor wafer IO which are rotating around the wafer disk rotation shaft 13 at a rate of about oor p m. The wafer disk 9 also includes a wafer cooling section 11 corresponding to the semiconductor wafers 10 and 10', and cooling water is circulated through the wafer cooling section 11 to cool the wafers 10 and 10'.

In addition, a mercury lamp 32 and a reflection plate 12 are placed above and below the ion beam passage port 5. A lamp chamber 4 having a shutter 15, cooling pipes 6, 7, etc. is provided, and the reflection plate 12 is tilted in a direction that allows light to easily hit the ion beam injection part. Further, the lamp chamber 2, which has the same configuration as the lamp chamber 4 and has a mercury lamp 31, a reflector 12, a shutter 15, cooling pipes 6, 7, etc., is located at a position other than the ion beam implantation position and when the wafer disk 9 rotates. In FIG. 1, seven locations are provided so that the semiconductor wafer is exposed to light relative to the location where the semiconductor wafer passes through.

8 is a feed through.

Note that the mercury lamp 3 is just one example; for example, in the case of a silicon semiconductor, the potential barrier of a silicon-silicon oxide film is 3.
Since the voltage is 2 eV, any lamp that can emit light with a wavelength of approximately 300 nm or less may be used.

Next, the operation of this device will be explained.

After evacuating the chamber 1 to below 10-'Pa, the wafer disk 9 carrying the semiconductor wafer is heated at 100° rpm.
Rotate to about m. When the rotation becomes stable, all the shutters 15 that cut off the light from the mercury lamp 3 that has been lit in advance are opened. In the manufacture of silicon semiconductor devices, if the mercury lamp 3 is too low, the effect will be small, and if it is too high, the mask material etc. will be damaged.

After that, ion beam implantation is started. In this series of operations, the ion beam implanter uses high-energy light irradiation to make the insulating film on the surface of the semiconductor conductive, allowing high energy to flow from the semiconductor surface or the electrodes, mask material, etc. on the surface to the semiconductor substrate side or surroundings. The ionic charge of the current density can be released. Furthermore, in order to completely remove the above-mentioned ion charges, high-energy light is irradiated onto the semiconductor wafer 10' from the lamp chamber 2 in addition to the ion implantation section.

As a result, the charge remaining on the wafer can be completely removed by the time the wafer disk 9 rotates from the ion implantation section and the wafer reaches the ion implantation section again.

It should be noted that the present invention can also achieve great effects when used in combination with a charge neutralization device using the same device configuration as that of the above-mentioned embodiments. In particular, surplus electrons from the charge neutralization device described above are completely removed from the wafer surface by irradiating high-energy light at a location other than the ion implantation area.

〔Effect of the invention〕

As explained above, the present invention is capable of applying energy to the surface of a semiconductor wafer relative to the wafer disk at a position where ions are implanted and at a position other than the position where ions are implanted, at a position along the rotational direction of the semiconductor wafer on the wafer disk. By equipping equipment that performs ion implantation while irradiating high-intensity light, it is possible to suppress the destruction of semiconductor devices due to charge-up of the wafer surface or the electrodes and mask material formed on the surface during ion implantation. have an effect.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
A cross-sectional view taken along the line A-A' in the figure, and FIG. 3 is a cross-sectional view showing a conventional example. 1...Chamber 2, 4...Lamp chamber 3...Mercury lamp 5...Ion beam passage port 6.7...
Cooling pipe 8...Feed through 9...Wafer disk 10.10'...Semiconductor wafer]j
...Wafer cooling section 12...Reflector plate 13...Wafer disk rotation shaft 14...Charge neutralization device Patent applicant NEC Corporation Figure 1

Claims (1)

[Claims] (1) An ion implantation device having an ion implantation section, a light irradiation section, and a wafer cooling section, the ion implantation section implanting ions into multiple semiconductor wafers individually based on a desired sequence. Yes, the light irradiation section irradiates the semiconductor wafer with light to eliminate charges on the wafer surface, and the wafer cooling section
An ion implantation device that cools a semiconductor wafer that has been irradiated with light.