JP3097118B2 - Ion implanter and setup method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a configuration of an ion implantation apparatus used in a manufacturing process of a semiconductor device and a method of setting up the ion implantation apparatus. In the ion implanter, which gives a desired energy to a required ion species generated by an ion source and selected by an analyzer, and injects it into a sample on a disk via a setup Faraday cup, An acceleration tube provided between the analyzer and the disk,
A single ammeter is arranged in the bias ring and the Faraday case, and the size of the ground aperture is variable.

The setup method is as follows. After performing the first setup by inserting the setup Faraday cup into the next stage of the analyzer of the ion implantation apparatus, the setup Faraday cup is removed, and then placed in the acceleration tube, the bias ring and the Faraday case. The second setup is performed by changing the size of the ground aperture while observing the ammeter.

[Industrial applications]

The present invention relates to a configuration of an ion implantation apparatus used in a manufacturing process of a semiconductor device and the like, and a setup method thereof.

In a manufacturing process of a semiconductor device, an ion implantation apparatus is heavily used to form an impurity region, and the present invention relates to an ion implantation apparatus in which the efficiency of implanted ions and the configuration of the apparatus for high-purity ion implantation are improved. And how to set it up.

[Conventional technology]

Currently, ion implantation equipment is a single-wafer medium-current device (ion current of 0.1 μA to several mA) that processes samples one by one, and a large-current device (several mA to 30 m) that batch-processes a large number of samples.
Although the present invention is classified into A), the present invention describes a high-current ion implantation apparatus that performs batch processing by rotating a sample stage on which a sample is placed.

FIG. 3 shows a main part of a conventional ion implantation apparatus, in which symbol 1 is an ion source, 2 is an analyzer (mass spectrometer), 3 is a setup Faraday cup, 4 is a first ground aperture, 5 is an acceleration tube, 6 is a first bias ring, 7 is a second ground aperture, 8 is a second bias ring, 9 is a third bias ring, 10 is a Faraday case, 11 is a disk (sample stage), and W is a wafer. (sample), a ₁ denotes an ammeter connected to the set-up Faraday cup, a ₂ is an ammeter connected to the Faraday case.

The outline of the operation is as follows. The ion beam generated by the ion source 1 is selected by the analyzer 2 only for the required ion species, and the flying speed is accelerated by the acceleration tube 5, that is, energy is given, and the accelerated ions are discarded. Wafer W on 11
Collision and injection. In addition, ions are implanted into a plurality of wafers one after another by rotating the disk 11. Usually, setup is performed at an initial stage in order to efficiently implant the wafer as a target.

The setup first inserted setup Faraday cup 3, to select the desired ion species and the current value while checking the current in ammeter A ₁ connecting to setup Faraday cup.

Thereafter, the setup Faraday cup 3 is removed, and the voltage applied to the acceleration tube 5 and the reverse bias voltage applied to the bias ring are adjusted to perform ion implantation on the wafer W. At that time, it necessarily current appearing ammeter A ₂ to be connected to a Faraday case 10 and the disk 11 is implanted ion current, also all approximately 10 ^-7 Torr member which is illustrated in the Figure 3 It is in a high vacuum.

[Problems to be solved by the invention]

By the way, in recent years, it has been desired to increase the current of the ion implantation apparatus, and for this purpose, the ion beam must be more efficiently implanted. Beam efficiency is the ratio of the implanted ion current to the current drawn from the ion source.

The ground aperture is a stop that changes the beam size, and the bias ring is a ring to which a reverse bias is applied to confine electrons outside the disk or Faraday case so that they do not escape. Since the aperture shape is fixed, there is a problem that a part of the ion beam hits the accelerating tube and the bias ring, causing spatter. The above-described setup has the purpose of reducing this hitting, but it is difficult to eliminate hitting entirely in the current setup. That is, in the conventional ion implantation apparatus, the beam size is determined by the ground aperture, but the beam efficiency is low because the beam size and shape change depending on the ion species and energy, and There is a disadvantage of hitting.

If the hitting occurs, particles fly out of the constituent members of the apparatus, and foreign ions are mixed into the implanted ions to cause cross contamination, thereby lowering the purity of the implanted ions.

On the other hand, since semiconductor devices are highly integrated and the influence of quality deterioration due to contamination is further increasing, prevention of cross contamination is an important measure.
For this reason, at present, passive measures are taken such that the constituent members of the ion implanter are made of a member which is relatively less affected by spattering (hitting) and foreign ions are mixed, for example, aluminum. I have.

In addition, the ion implanter has contamination with time and contamination introduced by a wafer (for example, contamination by a resist), and it is difficult to eliminate the contamination. For this reason, periodic cleaning is performed. However, there is a limit to the cleaning, and it is difficult to keep the contamination below a certain level.

The present invention proposes an ion implantation apparatus and a method of setting up the ion implantation aiming at reducing these problems, reducing particle contamination due to hitting as much as possible, and maximizing the beam efficiency. It is.

[Means for solving the problem]

The problem is that, as in the embodiment shown in FIG. 1, the desired ion species generated by the ion source 1 and selected by the analyzer 2 is given the desired energy and injected into the sample (wafer W) on the disk 11. In the ion implanter, the ammeters A ₃ , A ₄ , A ₅ , A ₆ , A ₇ are separately provided on the acceleration tube 5, the bias rings 6, 8, 9 and the Faraday case 10 provided between the analyzer and the disk. And the size of the ground apertures 14 and 17 is made variable.

The setup method is as follows: a setup Faraday cup 3 is provided next to the analyzer 2 of the ion implantation apparatus.
After the first set-up is performed by inserting the Faraday cup, the set-up Faraday cup is removed.
While observing the ammeters placed on the bias rings 6, 8, 9 and the Faraday case 10, the ground apertures 14, 17
Is changed so that the second setup is performed.

(Operation)

That is, according to the present invention, the ammeter is individually arranged on the accelerating tube, the bias ring, and the Faraday case to make the setup more accurate, and the size of the ground aperture is made variable. Perform setup. To do so, the current flowing through each member is observed to be zero, and the size of the ground aperture is made variable so that the implanted ion current increases.

The fact that the current flowing through the accelerating tube, the bias ring, and the Faraday case becomes zero means that there is no hitting, so that the beam efficiency can be improved and the hitting can be reduced.

〔Example〕

Hereinafter, the first embodiment will be described with reference to the drawings.
The figure shows a main part of the ion implantation apparatus according to the present invention, wherein reference numeral 1 denotes an ion source, 2 denotes an analyzer, 3 denotes a setup Faraday cup, 5 denotes an acceleration tube, 6 denotes a first bias ring, and 8 denotes a second bias ring. Bias ring, 9 is the third bias ring, 10
Faraday case, the 11 disks, W is a wafer, A ₁ denotes an ammeter connected to the setup Faraday cup, A ₂ is a current meter connected to the Faraday case, these members are similar to conventional devices. A variable-size ground aperture is disposed on the first ground aperture, and a variable-size first ground aperture and a second variable-size ground aperture 17 are also provided. In this embodiment, three bias rings are provided. Further, an ammeter A ₃ is provided in the accelerating tube 5, an ammeter A _{4 is provided} in the first bias ring 6, an ammeter A _{5 is provided} in the second bias ring 8, and a second ammeter A _{5 is provided} . The ammeter A ₆ is newly arranged on the 3 bias ring 9, and the ammeter A ₇ is newly arranged on the Faraday case 10.

The ground aperture is set so that current does not flow through these ammeters A ₃ , A ₄ , A ₅ , A ₆ , and A ₇ as much as possible and that a large current flows through the ammeter A ₂ connected to the disk 11. Perform setup (second setup) to adjust by changing the size of 14,17. FIG. 2 is a plan view of the ground apertures 14 and 17, and V indicates the aperture size. With such a configuration, they are adjusted to improve beam efficiency and eliminate hitting.

Next, the setup method according to the present invention will be described. First, as in the conventional setup, the setup Faraday cup 3 is inserted next to the analyzer 2 in the same manner as in the prior art, so that a large ion current of the required ion species is supplied to the setup Faraday cup. as appears at the 3 ammeter a _1, to adjust the ion source 1, the analyzer 2.

Next, when the first setup is completed, the setup Faraday cup is removed, and the second setup according to the present invention is performed. To do this, first, adjusted to current and ammeter A ₃ of the acceleration tube 5 by changing the aperture size of the first ground UPPER Chiya 14 ammeter A ₄ of the first bias ring 6 does not flow, and its Under the conditions, the aperture size is increased as much as possible so that the ion beam current is increased as much as possible. Thus, ammeter A ₃ and ammeter A ₄
Is monitored to eliminate hitting and increase the beam current. The beam current is monitored by the ammeter A ₂ which is connected to the disk. The first grand aperture
If 14 is made of silicon or a conductor coated with silicon, there is no risk of cross-contamination even when hitting it.

Then, ammeter A ₅ of the second bias ring 8 by changing the aperture size of the second ground UPPER Chiya 17, ammeter A ₆ of the third bias ring 9, ammeter A ₇ Faraday Case 10
Are adjusted so that the currents become zero, and the aperture size is expanded as much as possible under these conditions to increase the ion beam current as much as possible. Then, the beam current is read by the current meter A ₂ which is connected to the disk 11. At that time,
As the wafer W, a dummy wafer may be used,
Only the disk surface may be used.

Since the beam size and shape of the ion beam differ due to the difference in ion species and energy, the beam current can be made more efficient by setting it up as described above,
In addition, cross-contamination can be reduced by eliminating hitting.

Note that the setup according to the present invention described above can be not only a manual operation but also an automatic setup by computer control.

〔The invention's effect〕

As is apparent from the above description, according to the ion implantation apparatus and the setup method thereof according to the present invention, cross-contamination is reduced by preventing hitting, and ion beam efficiency is maximized under the conditions. And significantly contribute to the high quality and high performance of the semiconductor device.

[Brief description of the drawings]

FIG. 1 is a main part view of an ion implantation apparatus according to the present invention, FIG. 2 is a plan view of a ground aperture according to the present invention, and FIG. 3 is a main part view of a conventional ion implantation apparatus. In the figure, 1 is an ion source, 2 is an analyzer, 3 is a setup Faraday cup, 4 is a first ground aperture, 5 is an accelerating tube, 6 is a first bias ring, 7 is a second ground aperture, and 8 is a second ground aperture. Bias ring, 9 is a third bias ring, 10 is a Faraday case, 11 is a disk, 14 is a variable-size first ground aperture, 17 is a variable-size second ground aperture, W is a wafer, V is an aperture size, _{a 1, a 2, a 3} , a 4, a 5, a 6, a 7 represents an ammeter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01J 37/317 C23C 14/48 H01J 37/04 H01J 37/09

Claims (2)

(57) [Claims] 1. An ion implantation apparatus in which ion species generated in an ion source and selected by an analyzer are injected into a sample on a disk via a detachable setup Faraday cup before and after the setup, wherein the analyzer and the disk Between the analyzer and the disk, the accelerator arranged between the analyzer and the disk, the first, second and third bias rings, and the Faraday case. An ion implanter, characterized in that an ammeter is attached to each of them. 2. The method for setting up an ion implantation apparatus according to claim 2, wherein a desired ion species is selected by said analyzer so that an ion current flowing through said set-up Faraday cup in an inserted state is maximized. Performing the first setup for adjusting the ion source and the analyzer while observing with the ammeter, and then detaching the setup Faraday cup,
While observing with the ammeter, the ion current flowing through each of the accelerator, the first, second, and third bias rings, and the Faraday case is minimized.
A second setup for adjusting the aperture of each of the first, second, and third bias rings.