JPH06168696A - Method and device for ion implantation - Google Patents

Abstract

PURPOSE:To implant ions in different areas of a single wafer under different ion implantation conditions without causing metal pollusion or the like by arranging a deflecting means to deflect an ion beam according to its necessity. CONSTITUTION:Newly in a conventional device, a deflecting means 30 is arranged between an accelerating tube 14 and an Y-axis direction scanning means 16, and a beam damping part 32 is also arranged between the deflecting means 30 and the Y-axis direction scanning means 16. When ions are implanted in a silicon substrate 20, since voltage is not impressed upon the deflecting means 30, an ion beam collides with the substrate 20 and is implanted without being influenced by the deflecting means at all. When the ions are not implanted in the substrate 20, voltage is impressed upon the deflecting means 30. Thereby, the ion beam is deflected, and is discharged to the beam damping part 32, and the ion beam does not reach the substrate, and is not implanted. Thereby, ion implantation condition different areas can be formed easily in a single wafer by operating the deflecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus and an ion implantation method.

[0002]

2. Description of the Related Art Ion implantation is widely used in the manufacture of semiconductor devices, and is used, for example, to implant a group III or V ion into a silicon substrate to form a diffusion layer on the silicon substrate. The control accuracy of the impurity concentration and the depth of the diffusion layer in the ion implantation method is extremely excellent as compared with the case where the diffusion layer is formed by the thermal diffusion method. In order to manufacture a semiconductor device composed of a MOS type transistor and a bipolar type transistor, ion implantation is usually performed a plurality of times.

FIG. 6 shows a schematic diagram of a conventional ion implantation apparatus. The ion beam containing the ions generated by the ion source 10 passes through the mass analysis unit 12 and is accelerated by the acceleration tube 14. Then, the Y-axis direction scanning means 16 composed of electrodes
After being scanned in the Y-axis direction and the X-axis direction by passing through the X-axis direction scanning means 18, it collides with the silicon substrate 20 which is the workpiece placed in the sample chamber 22. This causes the ions to be implanted in the silicon substrate. An example of the voltage applied to the X-axis direction scanning means 18 is shown in FIG. An example of the voltage applied to the Y-axis direction scanning means 16 is shown in FIG. By applying a voltage having such a pattern to each scanning means,
As shown in FIG. 8, the ion beam is scanned.

In addition, there is also a method of scanning the ion beam with a magnetic field, or a method of relatively scanning the ion beam by fixing the ion beam and mechanically moving the workpiece.

[0005]

In recent years, the diameter of wafers has increased, and semiconductor device manufacturing lines using 8-inch wafers have become common. By the way, before performing ion implantation for the production of semiconductor devices, it is necessary to perform ion implantation conditions for optimizing ion implantation conditions such as ion implantation energy and dose amount.

Conventionally, ion implantation is performed on one entire wafer under one ion implantation condition. Therefore, when performing condition setting under a plurality of ion implantation conditions, the number of wafers corresponding to the number of condition setting is required. Alternatively,
For example, by changing the pattern of the voltage applied to the X-axis direction scanning means as shown in FIG. 9, the voltage pattern A in FIG.
Even when adopting the method of changing the dose amount per unit area in the desired wafer area corresponding to
Ion implantation is performed on the entire wafer.

From the viewpoint of economical use of the wafer, it is desirable that the ion implantation conditions can be determined by performing the ion implantation on one wafer under various conditions. That is, in one ion implantation condition setting, ion implantation is performed only on a certain wafer region, and ion implantation is not performed on the remaining wafer regions. Then, in the next ion implantation condition determination, if the ion implantation can be performed on the wafer region where the ion implantation is not performed, the ion implantation condition determination can be efficiently performed using one wafer.

Also, when manufacturing a small lot of semiconductor devices, that is, when ion implantation may be performed on a desired region of a wafer under certain conditions, at present, ion implantation is performed on the entire wafer under the same conditions. Has been given. In such a case, if ion implantation can be performed on different regions of one wafer under different ion implantation conditions, it is possible to form a plurality of types of semiconductor devices in one wafer.

An ion implanter having a gate for blocking the irradiation of the semiconductor substrate with an ion beam is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-263435. When the ion beam is blocked by such a gate, the gate is in a state of being sputtered by the ion beam. As a result, unnecessary metal ions are generated from the gate, which causes contamination of the semiconductor substrate.

Therefore, an object of the present invention is to provide an ion implanting apparatus and an ion implanting method capable of performing ion implantation under different ion implantation conditions, for example, in different regions of one wafer without causing metal contamination. It is in.

[0011]

In order to achieve the above-mentioned object, the ion implantation apparatus of the present invention for injecting an ion beam containing ions into a workpiece is, if necessary, an ion beam to the workpiece. A deflection means for deflecting the ion beam is provided so that it does not reach.

In the ion implantation apparatus of the present invention, the deflection means is means for forming an electrostatic field in the space through which the ion beam passes, or means for forming a magnetic field in the space through which the ion beam passes, and further, It is desirable to serve as the X-axis direction scanning means or the Y-axis direction scanning means.

In order to achieve the above object, the ion implantation method of the present invention for injecting an ion beam containing ions into a workpiece is an ion beam so that the ion beam does not reach the workpiece if necessary. Are deflected to form regions having different ion implantation conditions in the workpiece.

In the ion implantation method of the present invention, the ion implantation conditions are: ion species, ion implantation energy,
It may be any of the dose amounts or a combination thereof.

[0015]

Since the ion implantation apparatus of the present invention is equipped with the deflecting means for deflecting the ion beam so that the ion beam does not reach the workpiece, if necessary, only in a desired region of the workpiece, Ion implantation can be performed. Further, in the ion implantation method of the present invention, the ion beam is deflected as necessary so that the ion beam does not reach the object to be processed, thereby forming regions having different ion implantation conditions in the object to be processed, Ions can be efficiently injected into the workpiece. Since the unnecessary ion beam is discharged out of the system by the deflecting means, it is possible to prevent the generation of metal contamination due to the unnecessary ion beam.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

(Embodiment 1) FIG. 1 is a conceptual diagram of an ion implanter of Embodiment 1. In this ion implanter, the deflection means 30 is provided between the acceleration tube 14 and the Y-axis direction scanning means 16. Further, a beam dump unit 32 is provided between the deflecting unit 30 and the Y-axis direction scanning unit 16. Deflection means 30
Is means for forming an electrostatic field in the space through which the ion beam passes, and specifically, it can have the same structure as the conventional scanning means composed of electrodes. That is, a pair of electrodes made of aluminum or silicon may be arranged so as to face a space through which an ion beam passes, and a voltage may be applied to the electrodes. An electrostatic field is created by applying a voltage to the electrodes, which deflects the ion beam. Although well-known extraction electrodes, various control devices, and the like are also provided in the ion implantation device, their illustration and description are omitted.

As the ion source 10, a well-known one may be used, and for example, it may have a structure for generating plasma containing target ions from solid or gas. That is, for example, in the case of a solid source, the solid source is heated to a high temperature by a heater to generate a source vapor, which is caused to collide with electrons emitted from a filament to generate ions. When using gas,
The source vapor is only replaced by gas.

The mass spectrometric section 12 is composed of, for example, an electromagnet, and utilizes the mass difference of ions in the ion beam to introduce only ions having a specific mass into the acceleration tube 14.

The accelerating tube 14 is composed of a plurality of electrodes, and may have a known structure in which a voltage is applied to each electrode to accelerate the ion beam. The Y-axis direction scanning means 16 and the X-axis direction scanning means 18 arrange a pair of electrodes made of, for example, aluminum or silicon in the Y-axis direction and the X-axis direction so as to face the space through which the ion beam passes, and It is a structure that can apply a voltage. An electrostatic field is created by applying a voltage to each electrode, which causes the ion beam to scan.

FIG. 2 shows an example of the voltages applied to the X-axis direction scanning means 18, the Y-axis direction scanning means 16 and the deflecting means 30.

When ion-implanting a workpiece, for example, a silicon substrate 20 placed in the sample chamber 22, no voltage is applied to the deflecting means 30 ("A" in FIG. 2C).
Of time). Therefore, the ion beam is not affected by the deflecting means 30.

The ion beam containing the ions generated by the ion source 10 passes through the mass spectrometric section 12 and is accelerated by the acceleration tube 14. Then, after being scanned in the Y-axis direction and the X-axis direction by passing through the Y-axis direction scanning means 16 and the X-axis direction scanning means 18, it collides with the silicon substrate 20 which is the workpiece. This causes the ions to be implanted in the silicon substrate.

When the silicon substrate 20 is not ion-implanted, that is, when the ion beam is prevented from reaching the workpiece, a voltage is applied to the deflecting means 30 for deflecting the ion beam (((2) in FIG. 2). This corresponds to the time of "B" in C)). This deflects the ion beam,
It is discharged to the beam dump unit 32. In this way, ion implantation can be performed only in a desired region of the workpiece.

With the deflecting means 30 in the operating state, the ion beam is prevented from reaching the workpiece, and the ion implantation condition, which is any one of ion species, ion implantation energy, dose amount, or a combination thereof, is changed. After that, by making the deflecting means 30 inoperative, it is possible to easily form regions having different ion implantation conditions in the workpiece.

(Example-2) Example-2 is the same as Example-1.
The deflection means 30 is a means for forming a magnetic field in the space through which the ion beam passes. As shown in the conceptual diagram of FIG. 3, the deflection means 30, the Y-axis direction scanning means 16 and the X-direction
The axial scanning means 18 is composed of a well-known coil. That is, it is a structure in which a pair of coils are arranged so as to face a space through which an ion beam passes, and an electric current is passed through the coils. In the deflecting means 30, a magnetic field is formed by passing an electric current through the coil, which deflects the ion beam. In the Y-axis direction scanning means 16 and the X-axis direction scanning means 18, a magnetic field is formed by passing an electric current through the coil, and the ion beam is scanned thereby.

(Example-3) Example-3 and Example-1
As shown in the conceptual diagram of FIG.
The 0 and X-axis direction scanning means 18 are composed of well-known electrodes. The Y-axis direction scanning means is omitted, and a moving mechanism (not shown) for moving the workpiece in the Y-axis direction is provided in the sample chamber 22 instead of the Y-axis direction scanning means. The operation of the deflection means of the ion implanter of Example-3 is basically the same as that of the ion implanter of Example-1,
Detailed description is omitted. The deflecting means 30 and the X-axis direction scanning means 18 may be composed of known coils. Further, the deflection means and the Y-axis direction scanning means are composed of well-known electrodes and coils, the X-axis direction scanning means is omitted, and instead a moving mechanism for moving the workpiece in the X-axis direction is provided in the sample chamber. May be provided. Furthermore, in order to move the work piece in the X-axis direction and the Y-axis direction by replacing the deflection means 30 with a well-known electrode or coil, omitting the X-axis direction scanning means and the Y-axis direction scanning means. The moving mechanism may be provided in the sample chamber.

(Embodiment 4) Embodiment 4 and Embodiment 1
As shown in the conceptual diagram of FIG. 5, the deflecting means also serves as the Y-axis direction scanning means, and the deflecting means 30 and the X-axis direction scanning means 18 are composed of well-known electrodes. It should be noted that these may be composed of known coils.

When ion-implanting, for example, a silicon substrate 20 which is a workpiece placed in the sample chamber 22, a deflection voltage in addition to the scanning voltage is applied to the deflection means 30 which also serves as the Y-axis direction scanning means. Is applied. The ion beam containing the ions generated by the ion source 10 passes through the mass analysis unit 12 and is accelerated by the acceleration tube 14. Then, the light beam is deflected by passing through the deflection means 30 which also serves as the Y-axis direction scanning means, and is scanned in the Y-axis direction. Next, after being scanned in the X-axis direction by passing through the X-axis direction scanning means 18, it collides with the silicon substrate 20 which is the workpiece. This causes the ions to be implanted in the silicon substrate.

When the silicon substrate 20 is not ion-implanted, that is, when the ion beam is not allowed to reach the workpiece, no voltage is applied to the deflection means 30 which also serves as the Y-axis direction scanning means. The scanning voltage is the deflection means 3
It may be added to 0. As a result, the ion beam is not deflected and is ejected to the beam dump unit 32.

The deflecting means may also be used as the X-axis direction scanning means, and the deflecting means and the Y-axis direction scanning means may be constituted by known electrodes or coils.

Although the present invention has been described based on the embodiments, the present invention is not limited to these embodiments. The arrangement position of the deflecting means can be appropriately changed by forming the ion implantation device. Although the so-called post-acceleration type is illustrated as the ion implantation apparatus, the pre-acceleration type may be used. As the work piece, in addition to the silicon substrate,
A powder sample such as metal or chemical can be exemplified.

[0033]

According to the present invention, it is possible to perform ion implantation into desired plural regions of a workpiece under different ion implantation conditions. Therefore, a plurality of ion implantation conditions can be easily set using one wafer, which is economical. Further, for example, a plurality of types of semiconductor devices can be manufactured in one wafer. Furthermore, since the ion beam is discharged to the outside of the system (beam dump section) by the deflecting means, it is possible to prevent metal contamination due to unnecessary ion beams.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an ion implantation apparatus of Example-1.

FIG. 2 is a diagram showing an example of voltages applied to an X-axis direction scanning means, a Y-axis direction scanning means, and a deflection means.

FIG. 3 is a conceptual diagram of an ion implantation apparatus of Example-2.

FIG. 4 is a conceptual diagram of an ion implantation apparatus of Example-3.

FIG. 5 is a conceptual diagram of an ion implantation apparatus of Example-4.

FIG. 6 is a conceptual diagram of a conventional ion implantation device.

FIG. 7 is a diagram showing an example of voltages applied to an X-axis direction scanning means and a deflection means in a conventional ion implantation apparatus.

FIG. 8 is a diagram showing an ion beam scanning pattern in a conventional ion implantation apparatus.

FIG. 9 is a diagram showing another example of the voltages applied to the X-axis direction scanning means and the deflection means in the conventional ion implantation apparatus.

[Explanation of symbols]

 10 ion source 12 mass spectrometric section 14 acceleration tube 16 Y-axis direction scanning means 18 X-axis direction scanning means 20 workpiece 22 sample chamber 30 deflecting means 32 beam dump section

Claims (6)

[Claims] 1. An ion implantation apparatus for implanting an ion beam containing ions into a workpiece, comprising deflection means for deflecting the ion beam so that the ion beam does not reach the workpiece if necessary. An ion implanter characterized by: 2. The ion implanter according to claim 1, wherein the deflecting means is means for forming an electrostatic field in a space through which the ion beam passes. 3. The ion implanter according to claim 1, wherein the deflecting means is means for forming a magnetic field in a space through which the ion beam passes. 4. The deflection means is an X-axis direction scanning means or Y.
2. The device also functions as an axial scanning means.
The ion implanter according to item 1. 5. An ion implantation method for implanting an ion beam containing ions into a workpiece, wherein the ion beam is deflected so that the ion beam does not reach the workpiece, if necessary. An ion implantation method comprising forming regions having different ion implantation conditions in an object. 6. The ion implantation method according to claim 5, wherein the ion implantation condition is any one of ion species, ion implantation energy, dose amount, or a combination thereof.