JPH05144408A - Atomic beam implantation device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an elemental dielectric breakdown at the time when dopant is implanted into a semiconductor wafer by using non- chargeable beams, by detecting secondary ions released or emitted through impinging of a fixed target by electron beams before the performance of ion impingement by high-speed atomic beams, and controlling an atomic beam source on the basis of a dose obtained through the detection of the obtained secondary ions. CONSTITUTION:A high-speed electron beam measuring means 22 is moved to a position in front of a disk 4 before the implantation of a dopant, so that a high-speed atomic beam 23 released from a high-speed atomic beam source 21 may be received by the means 22 via an inlet opening 24 thereof. As regards, a solid target 31, a surface-forming substance thereof is sputtered by the incident atomic beams 23. Thereafter, by using a mass analyzer 32, emitted secondary ions of the sputtered substances are analyzed, and calculation is made of a dose of the atomic beams 23 incident upon the target 31. Dopant is implanted into a wafer 3 in accordance with the calculated dose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an atomic beam implanter,
More specifically, the present invention relates to an atomic beam implanter for implanting a dopant into a semiconductor wafer using a high speed atomic beam.

[0002]

2. Description of the Related Art In the semiconductor industry, a semiconductor wafer is doped with a small amount of a dopant such as phosphorus or arsenic,
The process of making the surface of the wafer a p-type semiconductor or an n-type semiconductor is essential. A thermal diffusion method, an ion implantation method, and the like have been proposed as a dopant implantation method in the related art, but at present, the ion implantation method is becoming the mainstream because the implantation amount or the dopant distribution to be implanted can be precisely controlled. FIG. 9 is a configuration diagram showing an example of an ion implantation apparatus used in this ion implantation method. In the figure, 1 is an ion source, 2 is a mass separation device, 3 is a semiconductor wafer, 4 is a disk on which the wafer 3 is mounted, 5
Indicates a Faraday cup, and 6 indicates an ion beam. The Faraday cup 5 is movable and is movably provided on the front surface of the disk 4 irradiated with the beam. Further, each of the above components is arranged in a vacuum container (not shown).

In this ion implanter, an ion source 1 ionizes and accelerates a dopant to be implanted in a semiconductor wafer 3 to emit an ion beam 6. Impurities are separated from the ion beam 6 while passing through the mass separation device 2, and bombard the surface of the wafer 3 on the disk 4.
At that time, since the kinetic energy of the ion beam 6 is very large, the ionic dopant penetrates into the inside of the wafer 3 to form a p-type or n-type semiconductor wafer. In such a semiconductor wafer, it is important that the dopant is always implanted in a constant amount. Therefore,
In the conventional technique, the Faraday cup 5 is moved immediately before the disk before starting the dopant injection, the ion beam 6 is received by the Faraday cup 5 and the electric quantity of the beam is measured. The ion source 1 is controlled so that Next, the Faraday cup 5 is moved again to retract from the path of the ion beam 6, and then ion implantation is started to bombard the ion beam 6 to stabilize the implantation amount of the dopant.

[0004]

However, in such a conventional method, since the ion beam 6 is charged, when the ions enter the wafer 3, the insulating structure of the element previously formed on the wafer is charged with ionic charges. Dielectric breakdown may occur due to discharge and / or discharge. Moreover, the Joule heat generated by the ion beam current may destroy the wiring in the element. Therefore, in the prior art, the yield of element manufacturing is significantly reduced due to these troubles. The present invention has been made in view of the above circumstances, and provides an atomic beam implanting apparatus for implanting a dopant by using an uncharged beam in order to prevent destruction of an element due to charging / discharging or Joule heat. The purpose is.

[0005]

The above object of the present invention is to mount a fast atom beam source for generating at least an electrically neutral atomic or molecular dopant, and a semiconductor wafer on which a fast atom beam is implanted. Disk, a solid target movably provided in front of the disk and impacted by an incident fast atom beam, and secondary ions emitted from the fixed target are detected, and the dose of the fast atom beam is measured from the intensity thereof. A high-speed atomic beam counting device having a mass spectrometer, wherein the high-speed atomic beam source is controlled based on the dose of the high-speed atomic beam measured by the high-speed atomic beam counting device To be achieved. Further, the above object of the present invention is to mount a semiconductor wafer on which a high-speed atomic beam source for generating at least an electrically neutral atomic or molecular dopant and a high-speed atomic beam are mounted, A rotatable disc provided with a slit for transmitting the high-speed atom beam in a region other than the solid disc, a solid target disposed behind the disc and impacted by the high-speed atom beam transmitted through the slit, and a fixed target. A high-speed atomic beam counter having a mass spectrometer for detecting the secondary ion and measuring the dose of the high-speed atomic beam from the intensity thereof,
It is achieved by an atomic beam implanting device characterized in that the high-speed atomic beam source is controlled based on a dose of the high-speed atomic beam measured by the high-speed atomic beam counting device.

Further, the above object of the present invention includes an ion source and a mass separator for removing impurities in the ion beam emitted by the ion source, and an ion neutralizer for neutralizing the ionic charge of the ion beam. Fast atomic beam source, a disk on which a semiconductor wafer on which a high speed atomic beam is implanted is mounted, a solid target movably provided on the front surface of the disk and bombarded by an incident high speed atomic beam, and the fixed target And a high-speed atom beam counter having a mass spectrometer for measuring the dose of the high-speed atom beam from the intensity of secondary ions emitted from the high-speed atom beam source, the high-speed atom beam source measuring the high-speed atom beam counter. It is achieved by an atomic beam implanter characterized by being controlled on the basis of the dose of the fast atom beam. Further, the above-mentioned object of the present invention includes a mass separation device for removing impurities in an ion beam emitted from the ion source and the ion source, and
A fast atom beam source having an ion neutralizer for neutralizing the ionic charge of the ion beam, and a semiconductor wafer on which a fast atom beam is implanted are mounted, and the fast atom beam is provided in an area excluding the semiconductor wafer. A slit having a slit for transmitting the light, a rotatable disc, a solid target placed behind the disc and impacted by the fast atom beam transmitted through the slit, and secondary ions emitted from the fixed target are detected to detect the intensity thereof. From a high-speed atom beam counter having a mass spectrometer for measuring the dose of the high-speed atom beam, and the high-speed atom beam source is controlled based on the dose of the high-speed atom beam measured by the high-speed atom beam counter. It is achieved by the atomic beam implanter characterized by the above.

[0007]

By performing the dopant implantation using an electrically neutral high-speed atom beam, it is possible to prevent the dielectric breakdown of the element due to the charging or discharging of ionic charges. Further, prior to the implantation, the high-speed atomic beam counter measures the dose of the atomic beam and controls the high-speed atomic beam source based on the measurement result, whereby the implantation amount of the dopant to be implanted can be precisely controlled.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an atomic beam implanter according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram for explaining the configuration of the first atomic beam implanting apparatus of the present invention, and FIG. 2 is a configuration diagram of a high-speed atomic beam counting apparatus applied to the apparatus of FIG. 1, respectively. In each of the following embodiments, the same reference numerals are used for the configurations having the same functions and actions as those of the conventional device shown in FIG. In FIG. 1, this atomic beam implanter implants a fast atom beam source 21 that accelerates and emits an electrically neutral fast atom beam 23 with a dopant such as phosphorus or arsenic, and the fast atom beam 23. Disk 4 on which the semiconductor wafer 3 can be mounted, and a high-speed atomic beam counting device 22 having a moving mechanism (not shown). The high-speed atomic beam counting device 22 can be inserted into or retracted from the position immediately before the disk front surface facing the atomic beam source 21 between the high-speed atomic beam source 21 and the disk 4 by its moving mechanism. It is possible. Although not shown in FIG. 1, the fast atom beam source 21 is fed back with the measurement result of a mass spectrometer 32 described later.

As shown in FIG. 2, the high-speed atomic beam counting device 22 has an inlet 24 through which the high-speed atomic beam 23 is introduced.
And a solid target 31 and a mass spectrometer 32 are arranged inside the structure.
The solid target 31 is arranged so as to be bombarded by the incident fast atom beam 23.

Next, the operation of the atomic beam implanter having the above-mentioned structure will be described. In this implanter, the high-speed atomic beam counter 22 is used for the disk 4 before the dopant is implanted.
Moved to the front. The fast atom beam counter 22 receives the fast atom beam 23 emitted by the fast atom beam source 21 through its inlet port 24. As a result, the solid target 3
In No. 1, the surface constituent substance is sputtered by the incident fast atom beam 23. The mass spectrometer 32 detects and analyzes the sputtered substances (secondary ions) emitted in an ionic state. Thereby, the amount of the sputtered substance on the target 31, and thus the dose of the fast atom beam 23 incident on the target 31 is calculated.

Generally, the secondary ion emission phenomenon from a solid surface hit by a high-speed atomic beam can be considered to be exactly the same as the secondary ion emission by a high-speed ion beam bombardment. If the target 31 is bombarded with an ion beam to calibrate the emission amount of secondary ions,
The dose of the fast atom beam 23 can be measured from the amount of secondary ions, and by feeding back the measurement result to the fast atom beam source 21, it is possible to control the amount of the fast atom beam 23 to be always constant. .. When the fast atom beam 23 is controlled to keep the dose constant, then the counting device 22 is retracted from immediately before the disk 4. And
A dopant such as phosphorus or arsenic is emitted from the fast atom beam source 21 as an electrically neutral fast atom beam 23, which bombards the wafer 3 mounted on the disk 4. As a result, the dopant is injected inside the wafer.

FIG. 3 shows the configuration of a second atomic beam implanter according to the present invention. The high-speed atomic beam counter used in this embodiment is the same as that shown in FIG. 2 except that it is fixedly arranged without a moving mechanism. Therefore, in this embodiment, the same reference numerals are used. The description of this counting device will be omitted using. This atomic beam implanter includes a high-speed atomic beam source 21 that accelerates and emits a dopant such as phosphorus or arsenic as an electrically neutral high-speed atomic beam 23, and a semiconductor wafer 3 into which the high-speed atomic beam 23 is implanted. It is composed of a disk 14 which can be mounted and is rotatable, and a high-speed atomic beam counting device 22. Disc 1
As shown in the front view of FIG. 4, 4 is provided with an appropriate number of slits 7 through which the high-speed atomic beam 23 is transmitted, in a basin other than a region where a plurality of semiconductor wafers 3 are mounted. In this embodiment, two slits 7 are provided in the diameter direction. Behind the disk 14, the high-speed atomic beam counting device 22 is fixedly arranged to measure the dose of the atomic beam by inflowing the high-speed atomic beam that has passed through the disk 14.

In the atomic beam implanter having the above-described structure, when implanting the dopant, the disk 14 first rotates to direct the slit 7 in the direction of entry of the high-speed atomic beam 23.
At this time, the high-speed atomic beam counting device 22 and the slit 7 are arranged so as to be aligned on a straight line, and the high-speed atomic beam 23 passing through the slit 7 flows into the high-speed atomic beam counting device 22. The high-speed atomic beam counter 22 includes a high-speed atomic beam 23.
Is measured as described above, and the measurement result is fed back to the fast atom beam source 21. Then disk 14
Rotates again to orient the wafer 3 in the direction of the fast atom beam 23. Then, the high-velocity atomic beam 23 can impact the wafer 3 and penetrate the inside of the wafer to inject the dopant.

As the high-speed atomic beam source applied to each of the embodiments shown in FIGS. 1 and 3, it is possible to use the one already proposed by the applicant in Japanese Patent Application No. 2-226486. The fast atom beam source according to this proposal improves the generation efficiency of fast atom beams by increasing the recombination efficiency of ions and electrons, and FIG. 5 shows an example of this fast atom beam source. That is, this high-speed atomic beam source 100 includes an ion source 107 that emits an ion beam 103,
Electrons having the same speed as the ions in the ion beam emitted by 107 and emitting an electron beam 123 in the same direction as the ion beam 103 and having a function of mixing the electron beam 123 with the ion beam 103. Gun (102,12
It consists of 1) and. The electron gun is an envelope.
It is composed of a filament 102 and an electron acceleration grid 121 arranged in 127. The fast atom beam source 100 configured as described above is generated by the filament 102 so that when the ion beam 103 emitted from the ion source 107 is introduced into the envelope 127, the ion beam 103 converges toward the ion beam 103. The electron beam 123 is mixed and accelerated by the electron acceleration grid 121. This allows the ion beam 103
The ions inside recombine with the electrons in the electron beam 123 and return to the atoms. Upon recombination, the ions have almost no change in kinetic energy and are inherited by the atoms as they are, generating a high-speed atomic beam 104 with a large kinetic energy, and the high-speed atomic beam injection hole 12
It is injected through the 8 to the outside of the envelope 127. Then, the fast atomic beam source 100 is operated by the electron beam 12 during the above process.
By adjusting the velocity of 3 to be approximately the same as that of the ion beam 103, the recombination cross section of ions and electrons can be increased and the generation efficiency of the fast atom beam 104 can be improved.

FIG. 6 shows the configuration of the third atomic beam implanting apparatus of the present invention. This atomic beam implanter obtains an uncharged high-speed atomic beam by passing an ion beam emitted from an ion source as shown in FIG. 9 as a conventional example through an ion neutralizer. The atomic beam source that emits the high-speed atomic beam thus obtained is replaced with the high-speed atomic beam source of the first atomic beam injector shown in FIG. Therefore, only the high-speed atomic beam source will be described here, and description of other parts will be omitted. The fast atom beam source 50 includes an ion source 51 and a mass separator 52 for removing impurities in the ion beam emitted by the ion source 51, and an ion neutralizer for neutralizing the ionic charge of the ion beam 54. 53 is arranged in a vacuum container 55. As the above-mentioned ion source, mass separation device and ion neutralizer, those known in the prior art can be used.
Ion neutralization can be performed efficiently by using the ion neutralizer already proposed in Japanese Patent Application No. 3-92322.

FIG. 7 shows an example of this ion neutralizer. The ion neutralizer 53 has a hollow container 221 having an ion beam entrance hole 209 at one end and a fast atom beam emission hole 210 at the other end and both ends closed, and one of titanium, magnesium, or aluminum. A hot filament 231 wound with a thin metal wire or ribbon selected from the above is contained in the hollow volume 221 and the ion beam entrance hole 209
And a metal vapor generation source 222 arranged so as to surround an axis connecting the high-speed atomic beam emission holes 210. The ion neutralizer 53 includes the ion source 51 and the mass separation device 52. In addition, as shown in FIG. 6, the high-speed atomic beam source 50 is configured by being arranged in a vacuum container 55. The ion neutralizer 53 receives the ion beam 54 emitted from the ion source from the ion beam entrance hole 20.
When the ions enter the inside of the hollow container 221 through 9, the ions contact the molecules of the metal gas vaporized by the metal vapor generation source 222 to lose the charge and are converted into fast atoms. Then, these fast atoms are emitted as the fast atom beam 23 from the fast atom beam emission hole 210. In this way, the ion neutralizer 53 can efficiently proceed the neutralization of the ions by making the ion beam enter the metal vapor and causing the ions to collide with the molecules of the metal gas.

FIG. 8 shows the construction of the fourth atomic beam implanting apparatus of the present invention. This atomic beam implanter replaces the fast atomic beam source shown in FIGS. 6 and 7 with the fast atomic beam source of the second atomic beam implanter shown in FIG. 2, and neutralizes ionic charges. The high-speed atomic beam 23 obtained by passing through the slit 7 of the fixedly arranged disk 14 is measured by the high-speed atomic beam counter 22. The operation process of this atomic beam implanter is as described above, and therefore its explanation is omitted.

[0018]

As described above, according to the atomic beam implanting apparatus of the present invention, by making the incident beam for ion implantation non-chargeable, the element previously formed on the semiconductor wafer can be charged with ion charges and / or charged. Dielectric breakdown does not cause dielectric breakdown. In particular, the uncharged nature of the incident beam is
In recent years, it is possible to completely prevent dielectric breakdown due to a decrease in dielectric strength caused by extreme miniaturization of elements and thinning of wiring in the elements. Further, the destruction of the wiring portion due to the Joule heat accompanying the inflow of the ion current can be completely prevented, and the production yield of the element can be greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration of a first atomic beam implanter of the present invention.

2 is a configuration diagram of a high-speed atomic beam counting apparatus used in the atomic beam implanting apparatus of FIG.

FIG. 3 is a schematic configuration of a second atomic beam implantation apparatus of the present invention.

FIG. 4 is a front view illustrating a state of a disk used in the atomic beam implanting apparatus of FIG.

FIG. 5 is a configuration diagram showing an example of a fast atom beam source applicable to the present invention.

FIG. 6 is a schematic configuration of a third atomic beam implantation apparatus of the present invention.

7 is a configuration diagram showing an example of an ion neutralizer applied to the atomic beam implanter of FIG.

FIG. 8 is a schematic configuration of a fourth atomic beam implantation apparatus of the present invention.

FIG. 9 is a configuration diagram of a conventional ion implantation apparatus.

[Explanation of symbols]

 3 Semiconductor Wafer 4,14 Disk 7 Slit 21,50 High Speed Atomic Beam Source 22 High Speed Atomic Beam Counter 23 High Speed Atomic Beam 31 Solid Target 32 Mass Spectrometer 51 Ion Source 52 Mass Separation Device 53 Neutralizer 54 Ion Beam 55 Vacuum Container

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location H01J 37/317 Z 9172-5E 49/26 7135-5E H01L 21/265 H05H 3/02 9014-2G (72) Inventor Yoshio Hatada 4-2-1 Motofujisawa, Fujisawa, Kanagawa Prefecture Ebara Research Institute, Ltd.

Claims (4)

[Claims] 1. A high-speed atomic beam source for generating at least an electrically neutral atomic or molecular dopant, a disk on which a semiconductor wafer on which a high-speed atomic beam is implanted is mounted, and a movably arranged front surface of the disk. And a fast atom beam counter having a mass spectrometer for detecting a secondary ion emitted from the fixed target bombarded by an incident fast atom beam and the secondary target emitted from the fixed target, and measuring the dose of the fast atom beam from its intensity. The atomic beam implantation apparatus is characterized in that the fast atomic beam source is controlled based on a dose of the fast atomic beam measured by the fast atomic beam counter. 2. A high-speed atomic beam source for generating at least an electrically neutral atomic or molecular dopant, and a semiconductor wafer on which a high-speed atomic beam is implanted are mounted,
A rotatable disk provided with a slit for transmitting the high-speed atomic beam in an area excluding the semiconductor wafer,
A mass spectrometer, which is arranged behind a disk, detects secondary ions emitted from the solid target bombarded by the high-speed atomic beam that has passed through the slit and the fixed target, and measures the dose of the high-speed atomic beam from the intensity thereof. A high-speed atomic beam counting device having, wherein the high-speed atomic beam source is controlled based on a dose of the high-speed atomic beam measured by the high-speed atomic beam counting device. 3. A fast atom comprising an ion source and a mass separator for removing impurities in the ion beam emitted by the ion source, and an ion neutralizer for neutralizing the ionic charge of the ion beam. A radiation source, a disk on which a semiconductor wafer is bombarded with a high-speed atomic beam, a solid target movably provided on the front surface of the disk and bombarded by a high-speed atomic beam incident thereon, and secondary ions emitted from the fixed target. And a high-speed atom beam counter having a mass spectrometer for measuring the dose of the high-speed atom beam from its intensity, wherein the high-speed atom beam source measures the dose of the high-speed atom beam measured by the high-speed atom beam counter. An atomic beam implanter characterized by being controlled based on the above. 4. A fast atom comprising an ion source and a mass separation device for removing impurities in the ion beam emitted by the ion source, and having an ion neutralizer for neutralizing the ionic charge of the ion beam. A radiation source and a semiconductor wafer on which a high-speed atom beam is to be mounted are mounted, and a slit which is provided with a slit for transmitting the high-speed atom beam in a region excluding the semiconductor wafer and is rotatable, and the slit arranged behind the disc And a fast atom beam counter having a mass spectrometer for detecting secondary ions emitted from the solid target bombarded by the fast atom beam that has passed through the fixed target, and measuring the dose of the fast atom beam from the intensity thereof. The fast atom beam source is controlled based on the dose of the fast atom beam measured by the fast atom beam counter. Atomic beam injector to collect.