JPS61168915A - Depositing method and depositing apparatus - Google Patents

Abstract

PURPOSE:To prevent the charge up in a work and to implement deposition having sufficient thickness, by neutralizing a deflected ion beam, whose image is formed, and projecting the beam on the work. CONSTITUTION:A neutralizer 20 applies a static electric field in a pair of electrodes and forms electron shower liquid so that it crosses an ion beam axis. The charge of ions in the ion beam, which is moved down along the beam axis, and the charge of the electrons in the electron shower are cancelled each other, and the ions are neutralized. A separator 21 forms an electric field in the pair of the electrodes and bends ions, which are not neutralized by the neutralizer 20, forcibly from the beam axis to the side part, so that the ions do not reach a wafer 30. Since the attached (deposited) ions are neutralized, the wafer 30 is not charged. The deposition can be continued for a desired time. Thus an Al film having a required and sufficient thickness can be formed.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a deposition method suitable for manufacturing a semiconductor device, and
In particular, the present invention relates to a deposition method and apparatus capable of uniformly depositing on minute parts using ions.

[Background technology]

Various deposition methods such as CVD, sputtering, and vacuum evaporation are used in the manufacturing process of semiconductor devices, especially in the process of depositing film materials on semiconductor wafers. Vacuum deposition method and sputtering method are often used for formation. However, in the vacuum evaporation method, the direction in which the metal fine particles to be deposited are landed on the wafer surface is not fixed, so there are small holes, for example, between the main surface of the wafer 4 and the main surface of the wafer 4 as shown in FIG. A is inserted into the contact hole 1 provided in the insulating film 5 for connection.
When filling the L material, the opening edge of the contact hole 1 becomes a shadow, suppressing the deposition on the bottom of the contact hole 1, and it is difficult to obtain uniform deposition. Since the deposition on the opening edge is faster than the deposition on the bottom, the AL of the opening edge is
The deposition progresses with the material 2 protruding from both sides, and when the two come into contact, a cavity 3 is created within the contact hole l. Such a cavity 3 causes an increase in the connection resistance in the contact hole 1 and a decrease in the reliability of the wiring, resulting in a decrease in the reliability of the semiconductor device. Moreover, such a problem occurs even in a sputtering method in which the deposition direction is relatively good.

For this reason, in recent years, a deposition method using an ion beam has been developed, and it is being investigated whether it can be used for deposition inside this type of microhole. In other words, "Applied Physics" No. 53
TC, No. 2 (1984), pages 88 to 91, discloses that if the ion energy is maintained within the range of 100 eV to IK eV, the projected ions will adhere to or be adsorbed on the surface of the workpiece. Therefore, using this technology, it is possible to deposit on a wafer, and since the ion beam has excellent directionality, it is thought to be able to prevent problems when depositing inside microholes, such as with vacuum evaporation or sputtering methods. .

However, in this type of deposition method using an ion beam, since the ions projected onto the workpiece have a charge, the charge is accumulated on the workpiece together with the ions at the time they are projected onto the workpiece, resulting in a so-called charge amplifier. This causes the ion to become charged and repel subsequent ions, making it impossible to project ions onto the workpiece. This limits the ion deposition time and allows for the deposition of the thickness required for AL wiring, etc. This is extremely difficult to do, which is why this type of ion technology has not yet been put into practical use.

[Purpose of the invention]

An object of the present invention is to prevent charge amplifiers in a workpiece in a deposition method using ions, and to enable deposition of a required thickness, thereby making it possible to achieve practical application of film deposition technology using the ion method. The purpose is to provide a method.

Another purpose is to provide a deposition method that utilizes the directionality of an ion beam to enable deposition into microholes, miniaturizes elements, and enables the manufacture of highly integrated semiconductor devices. .

Furthermore, another object of the present invention is to provide a deposition apparatus that can deposit ions to a required thickness without causing any charge amplification in the workpiece.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows. In other words, by neutralizing the imaged and deflected ion beam to be projected onto the workpiece and then projecting it onto the workpiece, char shear and pudding on the workpiece can be prevented, thereby making it possible to continuously project ions onto the workpiece. It is possible to achieve a sufficient thickness of deposition.

To neutralize the ion beam, the ion beam is passed through an electron shower that intersects with the ion beam collector so that the ion charges are canceled out by the electrons.

Furthermore, the ion beam is passed through an electric field to prevent unneutralized ions from being projected onto the workpiece, thereby reliably preventing charge amplification of the workpiece.

In addition to an ion source, an objective lens for ion imaging, and a deflector for deflection, the deposition apparatus also includes a neutralizer for neutralizing ions and a separator for separating unneutralized ions. By doing so, it is possible to neutralize the ions projected onto the workpiece, prevent charging of the workpiece, and achieve a sufficient and necessary thickness of ion deposition.

The neutral vessel has an electrode pair structure that forms an electron flow to intersect with the ion beam and cancel out the ion charges.

Further, the separator has an electrode pair structure that applies an electric field to intersect with the ion beam to forcibly change the projection direction of the charged ion beam.

〔Example〕

1 and 2 show the overall configuration of a deposition apparatus for carrying out the deposition method of the present invention. This device is constructed based on a known ion beam device, and is
An ion source 10 that generates ion beams of various ion species such as L and Si, a converging lens 11 that converges the ion beam emitted from the ion source 10, and a first lens for aligning the converged ion beam. The alignment deflector 12 for the next deflection and the ion species selection aperture 1 below it
A mass separator (hereinafter abbreviated as ExB quality ffi separator) 13 that combines an electric field and a magnetic field to select only the ion beam of the required ion species from the ion beam and pass it downward in cooperation with the ion beam 4. , a blanking electrode 15 that acts as a shutter for the ion beam, and an astigmatism corrector 16 .
It includes an alignment deflector 17 that performs secondary alignment deflection, an objective lens 18 that images the ion beam onto the wafer 30 below, and a deflector 19 that deflects the ion beam in the plane XY directions. The ion beam is equipped with a neutralizer 20 that neutralizes the ion beam, and a separator 21 that separates the ion beam that has not been neutralized. And X
The ion beam can be projected while scanning onto the wafer 30 placed f2 on the Y table 31.

The EXBili quantity separator 13 separates the respective trajectories according to the difference in ion species, and by appropriately changing the magnetic field strength, only the desired ion species travel straight along the beam axis, and the ion species selection aperture In cooperation with 14, this can be selectively extracted. Further, the blanking electrode 15 greatly bends the direction of the ion beam by controlling the magnetic field between the electrodes, thereby preventing the ion beam from being projected onto the wafer 30.

The neutralizer 20 applies an electrostatic field between the electrode pair 20A, 20A to form an electron shower flow that crosses the ion beam axis, and ions in the ion beam are moved downward along the beam axis. The charges with the electrons in the electron shower cancel each other out, neutralizing the ions. Furthermore, the separator 21 forms an electric field between the electrode pair 21A and 2LA, and forcibly bends charged ions, that is, ions that are not neutralized by the neutralizer 21, from the beam axis to the side. Avoid reaching above 30.

Therefore, according to the deposition apparatus having the above configuration, only the AL ions, for example, are selected from among the ion species emitted from the ion source 10 by the cooperation of the EXB mass separator 13 and the ion species selection aperture 14, and The ranking is passed through the pole 15, and the ion beam is imaged onto the surface of the wafer 30 by the objective lens 18 and deflected! In step S19, the image is projected onto a predetermined plane position. The ion beam after passing through the deflector 19 is transferred to an electrode 20A in the neutralizer 20.

The ions are passed through an electron shower oriented laterally in the electron shower 20A, and at this time, the electrons in the electron shower and the charge of the ions cancel each other out, and the ions are deprived of charge and are neutralized. Further, the ion beam is transmitted to the electrode 21 of the separator 21.
Although the ions are passed through the electric field between A and 21A, the neutralized ions are not affected in any way. however,
Ions that have not been neutralized in the neutralizer 2° still have charge and are deflected by the electric field in the separator 21, separated from the neutralized ions, and prevented from being projected onto the wafer 30.

Therefore, only neutralized ions are projected onto a predetermined position on the wafer 30, and by controlling the energy to be less than IK eV, the AL ions adhere to the wafer 30 and deposit AL.

Since the attached (deposited) ions are neutralized at this time, the wafer 30 is not charged (charged up), and the deposition can be continued for a desired period of time. This makes it possible to form an AL film with a necessary and sufficient thickness. For example, when filling the contact hole 33 formed in the insulating film 32 on the wafer 30 with AL as shown in FIG. Since the directionality is excellent, there is no lateral overhang at the edge of the opening, and uniform deposition AL34 can be obtained. Therefore, a cavity is not formed in the AL 34 of the contact hole 33, and an AL wiring with high reliability can be obtained.

Note that by controlling the magnetic field of the blanking electrode 15, projection of the ion beam onto the wafer 3o can be prevented, and this effect enables direct pattern deposition of the ion beam. In addition, when depositing St, E
The XBi amount separator 13 may be controlled.

〔effect〕

(1) When depositing by projecting an ion beam onto a workpiece such as a wafer, the ions are neutralized before being projected onto the workpiece, preventing charge-up of the workpiece and allowing continuous deposition to continue for the required time. can be carried out, and a deposited film of any thickness can be obtained.

(2) Since it is possible to deposit a desired thickness using an ion beam, its excellent directionality makes it possible to deposit into minute holes, making it possible to perform highly accurate filling without cavities. can.

(3) Since ions that are not neutralized are separated and prevented from being projected onto the workpiece, charging up of the workpiece can be reliably prevented.

(4) The ion deposition device is equipped with a neutralizer that neutralizes the imaged and deflected ion beam and a separator that separates unneutralized ions, so the ions to be projected onto the workpiece are neutralized. It is possible to prevent charge-up of the workpiece and achieve a desired thickness of deposition by projecting it onto the workpiece in a static state.

(5) Since each of the neutralizer and separator has an electrode pair structure, and it is only necessary to form an electron flow or an electric field between each electrode, the structure of the deposition apparatus can be simplified.

(6) The device of the present invention can be constructed by simply adding a neutralizer and a separator to a conventional ion beam device.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, the deposited material may be a material other than AL or Si, and any material that has been deposited by various methods up to now can be used as long as it can be generated as ions.

[Application field]

In the above explanation, the invention made by the present inventor has mainly been explained in the case where it is applied to the field of application which is the background of the invention, which is the deposition of film material into microholes in the manufacture of semiconductor devices, but the invention is not limited to this. It can be used for deposition when forming various films.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing the overall configuration of an embodiment of the present invention, FIG. 2 is a schematic side view of the main parts thereof, and FIG. 3 is a semiconductor deposited by the method of the present invention. FIG. 4 is a schematic cross-sectional view of a portion of the apparatus; FIG. 10... Ion source, 11... Converging lens, 12...
・Alignment deflector, 13...EXB mass separator,
14... Ion species selection aperture, 15... Blanking electrode, 16... Astigmatism corrector, 17... Alignment deflector, 18... Objective lens, 19... Deflector, 2
o... Neutral vessel, 21... Separator, 3o... Wafer (work), 31... XY table, 32... Insulating film, 33... Contact hole, 34... AL material . ,7)/Figure 3? 4 Figure 4

Claims (1)

[Scope of Claims] 1. When a deposited substance is made into an ion beam, imaged onto a workpiece such as a semiconductor wafer, and deflected to adhere and deposit on the workpiece surface, the ion beam after the deflection is neutralized. A deposition method characterized in that the film is projected onto a workpiece and deposited. 2. The deposition method according to claim 1, wherein the ion beam is neutralized by passing through an electron shower. 3. The deposition method according to claim 1 or 2, which comprises forcibly separating the ion beam that has not been neutralized after neutralizing the ion beam. 4. An ion source that emits the deposited material as an ion beam, and an objective lens that focuses the ion beam on the workpiece.
A deflector that deflects the ion beam, a neutralizer that neutralizes the imaged and deflected ion beam, and a neutralizer that neutralizes the unneutralized ion beam in the ion beam that has passed through the neutralizer. A deposition apparatus comprising: a separator for separating the ion beam from the ion beam. 5. The deposition apparatus according to claim 4, wherein the neutral vessel has an electrode pair structure that allows electrons to flow in a shower pattern so as to intersect with the ion beam. 6. The deposition apparatus according to claim 4 or 5, wherein the separator is a pair of electrodes to which an electric or magnetic field is applied so as to intersect the ion beam.