JPH01214019A - Apparatus for manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a uniform impurity concentration over the whole of the main face of a semiconductor substrate by installing the following: a means to measure the amount of an electric charge to be electrified on the semiconductor substrate when ions are implanted; a means to suppress electrification on the semiconductor substrate by feeding back a change in the measured amount of the electric charge to an ion implantation apparatus. CONSTITUTION:The following are installed: a means 50 to measure the amount of an electric charge to be electrified on a semiconductor substrate 10 when ions are implanted by using an ion implantation apparatus; a means to suppress electrification on the semiconductor substrate 10 by feeding back a change in the measured amount of the electric charge to the ion implantation apparatus. For example, when the semiconductor substrate 10 is irradiated with a beam current 30, a positive charge passes through a clamper 60 and an end station 20 and is absorbed by a ground; its current is usually constant. When the semiconductor substrate 10 is electrified by the positive charge, its electric current is reduced; a change in a value of the electric current flowing between the clamper 60 and the end station 20 is measured by using a small- current measuring instrument 50; the change is fed back to a beam-current generator 40; the beam current 30 is adjusted in order to suppress electrification by the positive charge.

Description

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

[Conventional technology]

As the degree of integration of semiconductor devices progresses, the circumference of the pattern becomes finer, and as a result of demands for higher accuracy in impurity doping and shallow PN junctions, impurity doping is almost entirely done by ion implantation.

Conventionally, when forming a diffusion layer of a MOS transistor, a high current ion implantation device was used to implant 75As and 31P+ at an ion beam current of about 6 mA to 8 mA.

An impurity source such as 11B+ is implanted, but as shown in FIG. 3, positive charges occur in the center of the semiconductor substrate 10 on the disk during ion implantation, creating a charged region 80. As a result, the ion beam is bent, resulting in a bent beam current 30, and the impurities at the center of the semiconductor substrate 10 are reduced from those at the outer periphery of the semiconductor substrate 10.

Note that the semiconductor substrate 10 is placed on the end stage fan 20,
It is fixed with a clamper 60.

[Problem to be solved by the invention]

The conventional ion implantation apparatus described above has the disadvantage that charging occurs in the center of the semiconductor substrate 10, making it impossible to obtain a uniform impurity concentration over the entire main surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for manufacturing a semiconductor device that solves the above-mentioned drawbacks and can provide a uniform impurity concentration over the entire main surface of a semiconductor substrate.

[Means to solve the problem]

The structure of the semiconductor device manufacturing apparatus of the present invention includes a means for measuring the amount of charge that is charged on a semiconductor substrate when ions are implanted in an ion implantation device, and a change in the measured amount of charge is fed back to the ion implantation device. The semiconductor substrate is characterized by comprising means for suppressing charging on the semiconductor substrate by doing so.

〔Example〕

FIG. 1 is a schematic diagram showing a semiconductor device manufacturing apparatus according to a first embodiment of the present invention. In the figure, a semiconductor substrate 10 is attached to an end station 20 and fixed with a clamper 60.

In this manufacturing apparatus, when the semiconductor substrate 10 is irradiated with the beam current 30, the positive charges pass through the clamper 60 and the end station 20 and are absorbed into the ground. This current is constant.

When a positive charge is applied to the semiconductor substrate 10, this current decreases. Therefore, the minute current measuring device 50 measures the change in the luminous current value between the clamper 60 and the end station 20, and calculates the change. amount of beam current generator 4
Adjust the beam current 30 by returning to 0,
Can suppress positive charge.

FIG. 2 is a schematic diagram showing a semiconductor device manufacturing apparatus according to a second embodiment of the present invention. In the figure, two semiconductor substrates 10, 11 are mounted on an end station 20 and are rotating. In this manufacturing apparatus, when the semiconductor substrate 10 is charged by the beam current 30, the induced voltage of the semiconductor substrate 11 is measured by the charge-up sensor 70,
It can be fed back to the beam current 30.

〔Effect of the invention〕

As explained above, the present invention measures the amount of charge on a semiconductor substrate and returns it to the beam current generator.
By adjusting the beam current and suppressing the charging on the semiconductor substrate,
This has the effect of uniformly doping impurities over the entire effective main surface of the semiconductor substrate.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a semiconductor device manufacturing apparatus according to a first embodiment of the present invention, FIG. 2 is a schematic diagram showing a semiconductor device manufacturing apparatus according to a second embodiment of the present invention, and FIG. FIG. 1 is a schematic diagram showing a conventional manufacturing device. 10.11... Semiconductor substrate, 20...
End station, 30...Beam current, 4
0... Beam current generator, 50...
Microcurrent measuring device, 60... Clamper, 70...
...Charge-up sensor, 80...Charged charge. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] Means for measuring the amount of charge charged on a semiconductor substrate when ions are implanted in an ion implantation device, and suppressing charging on the semiconductor substrate by feeding back changes in the measured amount of charge to the ion implantation device. 1. A semiconductor device manufacturing apparatus comprising: means.