JP3010640B2 - Semiconductor device manufacturing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A method and an apparatus for manufacturing a semiconductor device, in particular, a region beyond a substrate region is scanned with an ion beam to implant ions into the substrate, and the ions are accumulated in the substrate by the implantation. Regarding ion implantation in which electron irradiation is performed to neutralize a positive charge, the method is intended to prevent the electron irradiation from accumulating excessive negative charges exceeding neutralization on a substrate. When the scanning point is located outside the vicinity of the periphery of the substrate, the irradiation of the electron beam is interrupted. In the apparatus, a disk, an ion beam source, a scanning controller, an electron gun, an electron gun controller, The disk has a disk shape, a plurality of substrates are arranged side by side on a peripheral portion of the main surface, and the substrate is rotatable. The ion beam source emits an ion beam of predetermined ions to the disk. The scanning controller scans the ion beam in the radial direction of the disk and can recognize the scanning point, and the electron gun scans the ion beam on the disk. The region is irradiated with electrons, and the electron gun controller is configured to be able to control the on / off of the irradiation by the electron gun based on the information on the ion beam scanning point recognized by the scanning controller.

[Industrial applications]

The present invention relates to a method for manufacturing a semiconductor device and an apparatus therefor, and more particularly, to scanning a region beyond a substrate region with an ion beam to implant ions into the substrate and neutralizing positive charges accumulated on the substrate by the implantation. Ion implantation for performing electron irradiation for performing ion implantation.

In the manufacture of semiconductor devices, ion implantation has been awarded for introducing impurities into a substrate. As a device used for the ion implantation, there is a high-current ion implantation device in which an ion beam current is increased. In such an apparatus, since the amount of positive charges accumulated in the insulating film on the substrate or the conductive layer on the insulating film due to ion implantation increases, the device on the substrate may be damaged, and the accumulated charge is neutralized. In some cases, electron irradiation is performed. At this time, when the element is fine, it is necessary to control electron irradiation so that the element is appropriately neutralized.

[Conventional technology]

2 (a) and 2 (b) are a main part configuration diagram of a conventional example of an ion implantation apparatus for performing the above-described electron irradiation and a partial front view of a disk thereof.

In the figure, 1 is a disk, 2 is an ion beam source,
Reference numeral 3 denotes a scanning controller, 4 denotes an electron gun, 5 denotes an electron gun controller, and S denotes a substrate (wafer) to be ion-implanted.

The disk 1 has a disk shape, holds a plurality of substrates S side by side on a peripheral edge of a main surface, and rotates by driving a motor 1a. The diameter of the disk 1 is, for example, about 60 cmφ, and the rotation speed is, for example, about 1000 rpm.

The ion beam source 2 receives the implanted ions (for example, when the substrate S is Si
In this case, the ion beam 2a of B ⁺ , P ⁺ , As ^+, etc.) is emitted toward the peripheral portion of the main surface of the disk 2. The diameter of the ion beam 2a is 15 to 20 mmφ at the position of the main surface of the disk 2, and its current is, for example, about 4 mA. Generally, an ion implanter having a maximum ion beam current of 10 mA or more is referred to as a high current type.

The scanning controller 3 has a deflection mechanism 3a for deflecting the ion beam 2a and a control unit 3b for controlling the same, and scans the ion beam 2a in the radial direction of the disk 1. . The length of the scanning area A (shown in (b)) is set so as to exceed the area occupied by the substrate S passing by the rotation of the disk 1. The time for one scan is, for example, about several seconds.

The electron gun 4 irradiates the scanning area A of the ion beam 2a on the disk 1 with electrons. The irradiation area is indicated by B in (b). As described above, this electron irradiation supplies a negative charge to the substrate S in order to neutralize a positive charge accumulated in the substrate S from the ion beam 2a at the time of ion implantation.

The electron gun controller 5 controls the electron gun 4 so as to adjust the intensity of the electron irradiation.

Then, the ion implantation using this apparatus is performed while adjusting the intensity of the electron irradiation so that the magnitude of the current due to the electron irradiation becomes equal to the magnitude of the current due to the ion beam 2a, and rotating the disk 1 holding the substrate S. Ion beam
2a is scanned, and during the period, the electron irradiation is performed continuously.

[Problems to be solved by the invention]

However, when the ion implantation is performed in this manner, when the scanning point of the ion beam 2a is on the substrate S, the substrate S
The positive charges accumulated in the substrate S are appropriately neutralized, but when the scanning point of the ion beam 2a is located outside the periphery of the substrate S, the accumulation of the positive charges on the substrate S is stopped. In some cases, the supply of negative charges due to electron irradiation is continued, and the amount of negative charges accumulated on the substrate S becomes excessive, thereby damaging elements on the substrate S as in the case of positive charges.

Accordingly, the present invention provides a method and apparatus for manufacturing a semiconductor device, and in particular, scans a region beyond a substrate region with an ion beam to implant ions into the substrate and neutralizes positive charges accumulated on the substrate by the implantation. The purpose of the present invention is to prevent the electron irradiation from accumulating excessive negative charges exceeding neutralization on the substrate.

[Means for solving the problem]

The above object is to perform ion implantation into a scan region including a substrate by using an ion beam controlled by a scan controller, and to neutralize a positive charge accumulated on the substrate by the implantation. In the method of manufacturing a semiconductor device for irradiating the scanning region with electrons, the electron irradiation is performed by an electron gun controller, and the electron gun controller recognizes that the scanning point of the ion beam is outside the vicinity of the periphery of the substrate. The information is obtained from the scan controller, which is achieved by a method of manufacturing a semiconductor device that interrupts electron irradiation, and further includes a disk, an ion beam source, a scan controller, an electron gun, and an electron gun controller, The disk has a disk shape, and is capable of holding a plurality of substrates side by side on a peripheral portion of a main surface and is rotatable. The scan controller emits an ion beam of constant ions toward a peripheral portion of the main surface of the disk, and the scan controller causes the ion beam to scan in a radial direction of the disk and recognizes a scan point thereof. The electron gun irradiates the scanning area of the ion beam on the disk with electrons, and the electron gun controller uses the information of the scanning point of the ion beam recognized by the scanning controller to generate the electron beam. This is achieved by a semiconductor device manufacturing apparatus for controlling on / off of the electron irradiation by a gun.

(Operation)

Since the above interruption of electron irradiation is almost synchronized with the interruption of positive charge accumulation on the substrate that occurs when the scanning point of the ion beam protrudes from the substrate area, the electron irradiation appropriately neutralizes the positive charges accumulated on the substrate. However, excessive accumulation of negative charges on the substrate is eliminated.

In the apparatus, the above-described interruption of the electron irradiation can be performed because the scan controller can recognize the scanning point of the ion beam and the electron gun controller can control on / off of the electron irradiation based on the recognition information. It is possible.

〔Example〕

Hereinafter, the first embodiment of the method and the apparatus according to the present invention will be described.
This will be described with reference to FIGS. Fig. 1 (a) (b)
FIG. 1 is a main part configuration diagram of an embodiment of an ion implantation apparatus for carrying out a method of the present invention and a partial front view of a disk thereof. The same reference numerals indicate the same objects throughout the drawings.

In this figure, the ion implantation apparatus is different from the conventional scanning controller of the ion implantation apparatus described in FIG.
The electron gun controller is changed from 5 to 5A instead of 3A, and the information signal of the scanning controller 3A is sent to the electron gun controller 5A.

Since the disk 1, the ion beam source 2, and the electron gun 4 are the same as the conventional example, the description is omitted.

The scanning controller 3A is obtained by replacing the control unit 3b of the scanning controller 3 with a control unit 3c for adding a function, and scans the ion beam 2a in the radial direction of the disk 1 similarly to the scanning controller 3. As in the case of the scanning controller 3, the length of the scanning area A (shown in (b)) is equal to the length of the substrate S passing by the rotation of the disk 1.
Is set so as to exceed the area occupied by the scan, and the time for one scan is, for example, about several seconds.

Here, a function added from 3b of the control unit 3c is that the scanning point of the ion beam 2a is recognized and the information can be output as an electric signal. More specifically, since the amount of deflection of the ion beam 2a is in accordance with the signal level sent from the control unit 3c to the deflection mechanism 3a, an appropriate point is taken from the signal level as scanning point information.

The electron gun controller 5A controls the electron gun 4 so as to adjust the intensity of electron irradiation similarly to the electron gun controller 5, and further controls the ion beam output from the scanning controller 3A.
On / off of the electron irradiation can be controlled by the information signal of the 2a scanning point.

Then, referring to (b), the period of the electron irradiation by ON / OFF is set to be only when the scanning point of the ion beam 2a is located at the portion C in the scanning area A. In other words, when the scanning point of the ion beam 2a deviates from the electron irradiation period C, the electron irradiation is interrupted.

At this time, the starting point and the ending point of the electron irradiation period C are set so that the scanning point of the ion beam 2a passes at or near both side edges of the area occupied by the substrate S passing by the rotation of the disk 1. This setting is
In 3A, this is performed by taking an appropriate point from the signal level sent from the control unit 3c to the deflection mechanism 3a. For example, assuming that the length of the scanning area A is 100 and the area occupied by the substrate S passing therethrough is 15 to 80, the starting point and the ending point of the electron irradiation period C are set to 15 and 80 or 20 and 75 close thereto. And so on.

In the ion implantation using this embodiment, the intensity of electron irradiation is adjusted to the current of the ion beam 2a and the substrate S
Beam 2a while rotating the disk 1 holding the
Is performed by scanning.

There, when the scanning point of the ion beam 2a is on the substrate S, the positive charges accumulated on the substrate S are appropriately neutralized,
Of course, when the scanning point of the ion beam 2a is located substantially outside the region occupied by the substrate S passing through the scanning region A, that is, the scanning point of the ion beam 2a is approximately outside the periphery of the substrate S. When this happens, the electron irradiation is interrupted and the substrate S
Does not cause the problem of the conventional example that excessive negative charges are accumulated in the semiconductor device.

The present inventor, when ion implantation into a substrate having a gate electrode formed on a gate insulating film in the formation of a fine FET,
In contrast to the conventional example in which the gate insulating film has been broken, the embodiment can be used to eliminate the occurrence of the breakdown.

The specifications of each part of the device are not limited to the embodiments. In addition, when the scanning direction of the ion beam is closer to the scanning direction of the ion beam, for example, when the scanning speed of the ion beam is faster than the rotation speed of the disk, the electron irradiation is turned on and off. The electron irradiation period C may be set to a plurality of different lengths so as to approach the periphery of the substrate for each scan.

[Effects of the Invention] As described above, according to the configuration of the present invention, a method of manufacturing a semiconductor device and an apparatus therefor, in particular, a region beyond a substrate region is scanned with an ion beam to implant ions into the substrate, and Regarding ion implantation for performing electron irradiation to neutralize positive charges accumulated on a substrate by implantation, electron irradiation can prevent the substrate from excessively accumulating negative charges exceeding neutralization, This has the effect of enabling stable formation of fine elements.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are a main part configuration diagram and a partial front view of a disk of an embodiment of an ion implantation apparatus for carrying out the method of the present invention, and FIGS. Fig. 2 is a configuration diagram of a main part of Fig. 1 and a partial front view of the disk. In the figure, 1 is a disk, 1a is a motor, 2 is an ion beam source, 2a is an ion beam, 3 and 3A are scanning controllers, 3a is a deflection mechanism, 3b and 3c are control units, 4 is an electron gun, and 5 and 5A are An electron gun controller, A is a scanning area, B is an electron irradiation area, C is an electron irradiation period, and S is a substrate.

Claims (2)

(57) [Claims] An ion beam controlled by a scan controller is used to implant ions into a scan area including a substrate, and to neutralize a positive charge accumulated on the substrate by the implantation. In the method of manufacturing a semiconductor device for irradiating the scanning region with electrons, the electron irradiation is performed by an electron gun controller, and the electron gun controller recognizes that the scanning point of the ion beam is outside the vicinity of the periphery of the substrate. A method of manufacturing a semiconductor device, comprising: obtaining information from the scan controller and interrupting electron irradiation. 2. A disk, an ion beam source, a scanning controller, an electron gun, and an electron gun controller, wherein the disk has a disk shape and a plurality of substrates are arranged on a peripheral portion of a main surface. The ion beam source emits an ion beam of predetermined ions toward the periphery of the main surface of the disk, and the scan controller outputs the ion beam to the disk. The electron gun irradiates the scanning area of the ion beam on the disk with the electrons, and the electron gun controller controls the scanning by the electron gun controller. An apparatus for manufacturing a semiconductor device, wherein on / off of the electron irradiation by the electron gun is controlled based on information on a scanning point of the ion beam recognized by a controller.