JPS5887748A - Ion-beam implantation device - Google Patents

Abstract

PURPOSE:To obtain an ion-beam implantation device, which can perform automatic correction by easily carrying out oscillation of an ion source, by providing a computing element which obtains the vertical and the horizontal shifts of the gravitational center of an ion beam so as to measure the shifts of the gravitational center of the ion beam. CONSTITUTION:The current output values I1-I9 of Faraday cups group 6 are input into a computing element 7. Next, the computing element 7 obtains the vertical and the horizontal shifts from the central position of the gravitational centers of an ion beam 2 on an exposure surface 5, and thus obtained value is fed back to rotary electric motors 8 and 9. Then, the motors 8 and 9 oscillate an ion source 1 through drive-shaft switching mechanisms 10 and 11 so as to correct the axis of the ion beam 2. Owing to the above constitution, since the surface 5 is provided with the plural Faraday cups 6, and the oscillating mechanisms 8, 9, 10 and 11 are controlled by feeding back the gravitational shift of the beam 2 to the ion source 1, the ion source almost doesn't require its installation accuracy. In addition, control of the axis of the beam 2 can be remarkably easily carried out during the exchange of the ion source 1.

Description

[Detailed description of the invention] The present invention relates to improvements in ion implantation equipment.

In an ion implantation device, the ion beam emitted from the ion source is directed toward the surface of the target object (for example, the surface of a semiconductor silicon;
It is necessary to match the top accurately, but it is not easy.

The conventional method is shown in FIG. In the vg1 diagram, the beam axis correction of the beam 2 emitted from the ion source 1 is performed by measuring the amount of current that reaches the Faraday cup 3 placed on the subject surface with a detector (DC ammeter) 4, and when the indication of the detector 4 reaches the maximum. I had to manually adjust the neck of the ion source 1 to make sure that it was correct. but,
With this method, it is not possible to know where the center of gravity of beam 2 is. For example, it is unsuitable when high-precision uniform implantation into a semiconductor sample is required.

In addition, the characteristics of the ion source 1 may deteriorate due to electrode contamination, etc., so please replace the ion source 1 (or replace the ion source 1 within an appropriate period).
It is necessary to clean and replace the electrodes inside.

Therefore, it is necessary to correct the deviation of the beam axis each time, and the above-mentioned adjustment work is troublesome.

The present invention has been made with the above points in mind.1) Ion beam implantation that makes it possible to measure the center of gravity shift of the ion beam and automatically correct it by easily shaking the ion source. It provides equipment.

Hereinafter, the present invention will be explained with reference to Examples.

FIG. 2 is a diagram illustrating an embodiment of the present invention.0 An ion beam 2 emitted from an ion source 1 reaches a surface 5 of a target object. A plurality of Faraday cup groups 6 are provided on the object surface S to measure the density distribution of the ion beam 2. Third
The figure shows an ion beam 2 in the vertical (or horizontal) direction of the target surface 5.
, where gltll is the ion current value equivalent to a unit area, and the horizontal axis is the distance dimension of the vertical Y (crosswise C and horizontal X) of the object surface 5. In the figure, a curve 12 indicates the beam density (distribution characteristics), and solid lines 13, etc. indicate the detection cylinder 1 flow values 1, .about.■, of each Faraday cup.

The deviation of the beam axis is corrected by aligning the center of gravity of the beam with the center position of the center and center of the object surface 5.

In FIG. 2, each current output value 11~ of the Faraday cup group 6
I, is input to the numbing device 7, and the beam device 7 calculates the center position on the object surface 5 and the vertical and horizontal weighting point deviations Δy, ΔX, and Narichi, where n: Number of Faraday cups in the vertical or horizontal direction.

I, , I,: Detected current value of the Faraday cup at any position in the vertical or horizontal direction.

"/1 + xH" Distance from the reference 1tllll end of the Faraday cup in the vertical or horizontal direction.

yc, x: N1 or stomach at the center of the lateral object plane.

is calculated, and the value is assigned to the rotating electric motors 8 and 9.

The electric motors 8 and 9 swing the ion source 1 through the frame axis converters mlo and 11, and the beam axis of the ion beam 2 is corrected.

In this manner, a plurality of Faraday cups are provided on the irradiated object surface 5, the deviation of the beam center of gravity is returned to the ion source 1, and the ion source 1 is controlled by controlling the neck tilting drive mechanism 8, 9, 10.11. There is almost no need for precision in pitching the head, and alignment of the beam at the time of replacing the ion source 1 can be performed extremely easily.

In the above embodiment, nine Faraday cups were used as an example, but the present invention is not limited to this number and can be applied as appropriate.

Next, an application example of measuring the weighted point of a beam using a plurality of Faraday cups will be described below.

FIG. 4 shows a rotation scanning type which is one of the ion implantation methods. In this method, an implanted sample (semiconductor wafer 8, etc.) 15 is placed on a rotating disk 14, and the ion beam 2 is
口＜It is something to be typed. At this time, the disk 14 is the sample 15
On the surface - 〇 Vertical feed speed of the weave where beam 2 hits uniformly #v
R to VR, A/)L ・・・・・・・・・・・・・・・Middle・
...+3) Here, 1%: Any point where the beam hits the disk. Radius A from the center of the disk: A constant determined by the amount of indentation dose, etc., that is, any surface on the disk 14. It is necessary to rub the beam 2 so that the 101 turning angular speeds scanned by the beam 2 are the same.

In such a device, in order to accurately know the position of the radius R of the beam 2 that hits the disk 14, several Faraday cups 16 (a plurality of Faraday cups 16 are arranged in tandem in the radial direction of the disk 14) on the axis of one beam 2 are used. is provided, the vertical weighting point Δy of the beam 2 is determined from the above equation (1), and the value of the radius R of the lead portion between the Faraday cup 16 and the disk 14 is corrected.

Note that when measuring the load on one beam 2, the disk 14 is moved to the field below the beam 2 axis, and when beam 2 reaches the Faraday cup 16, the weight point is determined and the value is memorized. The value of R is corrected when the disk 14 is raised (or lowered).

As described above, the present invention makes it possible to easily align the center of gravity of an ion beam, has a wide range of neutrality, and has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the prior art, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a characteristic diagram thereof, and FIG. 1′;/1. 1... Ion source, 2... Ion beam, 360. Faraday cup, 5... object surface, 6... Faraday force. P group, 7... Arithmetic unit, 8, 9, 10, 11... Swing drive mechanism agent Patent attorney Toshiyuki Usuda 3 A) No F? ] ':AZ Figure 3 Figure Separate 11 4th Shi-[ ↑ Two spiders ↓ 76

Claims (1)

[Claims] 1. An ion source that emits an ion beam, a plurality of 7-Aladekas, which are arranged regularly in the vertical and horizontal directions on the surface of the object onto which the ion beam is incident, a detector that detects the value of the ion current flowing in the beam, and a calculation that uses the detected ion current value to determine the shift of the weight point in the vertical and horizontal directions of the ion beam with respect to the center position on the surface of the target object. and a driving means for oscillating the ion source in accordance with the shift in the weighting point of the ion beam to align the center of gravity of the ion beam with the center of the surface of the object to be irradiated. Ion beam implantation equipment.