JPH01312071A - Sputtering device - Google Patents

Abstract

PURPOSE:To facilitate the replacement of targets and the production of targets and target-holding means by forming targets into plate-like shapes and also constituting target-holding means by using a polygonal cylinder capable of being divided into plural plate parts according to the shapes of the targets. CONSTITUTION:A plasma production chamber 1 and a specimen chamber 3 are evacuated to the prescribed values, respectively, and then, while introducing Ar gas into the production chamber 1, microwaves are introduced via a microwave guide 2. Simultaneously, a magnetic field is formed in the production chamber 1 by means of an exciting coil 4 and electron cyclotron resonance conditions are set up to produce the plasma of Ar, which is introduced into the specimen chamber 3 via a plasma-drawing window 1c by means of the divergent magnetic field formed by the exciting coil 4. Then, targets 6 on which negative voltage is impressed are sputtered, and a film is formed on the surface of a substrate S as a specimen. At this time, the targets 6 are formed into plate-like shapes, and holding means 9 holding the above targets 6 are formed into plate-like shapes according to the shapes of the targets 6 and are constituted of a polygonal cylinder capable of being divided into plural plane parts, and further, permanent magnets are provided to respective plane parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus that uses plasma generated by electron cyclotron resonance excitation using microwaves.

[Prior art]

Generally, as a method for forming thin films on sample substrates in the manufacturing process of electronic devices such as semiconductor integrated circuits, chemical vapor deposition (CVD), which uses plasma generated mainly by high-frequency discharge, is used to form silicon-based thin films.
The sputtering method has mainly been used to form thin films of metals or metal compounds.

However, although the sputtering method can easily supply metal atoms and has a fast film formation rate, it is difficult to control the film, and there are also problems with the density of the film.

As a countermeasure to this problem, electron cyclotron resonance (ECR: El
ectron Cyclotron Re5onanc
An ECR sputtering method using plasma generated using
No. 8, JP-A-60-50167, JP-A-61-114
518 etc.).

FIG. 4 is a schematic vertical cross-sectional view of a conventional ECR sputtering apparatus, in which reference numeral 31 indicates a plasma generation chamber;
32 is a microwave waveguide, 33 is a sample chamber, and 34 is an excitation coil.

At the center of the upper wall of the plasma generation chamber 31 is a quartz glass 31a.
A circular plasma extraction window 31c is provided at the center of the lower wall opposite to the microwave introduction window 31b, and one end of the microwave waveguide 32 is connected to the microwave introduction window 31b. , and the plasma drawer window 31c
A sample chamber 33 is arranged facing the plasma generation chamber 31 and a microwave waveguide 32 connected thereto.
An excitation coil 34 is provided around one end of the excitation coil 34 so as to surround the excitation coil 34 .

In the sample chamber 33, there is a sample stage 35 on which a sample substrate S is placed facing the plasma extraction window 31c, and a sample stage 35 for sputtering is placed facing the periphery immediately below the opening of the plasma extraction window 31c in the sample chamber 33. Target 36 is shield case 37
It is enclosed and arranged in. The target 36 is formed in a short cylindrical or conical shape in accordance with the shape of the plasma extraction window 31c so as to surround the plasma flow, and a ring member 38 made of soft iron or a magnet in a ring shape is closely attached to the outer diameter side of the target 36. (See Figure 5). and the top, excluding its inner peripheral surface.

The lower end surface and outer peripheral surface are covered with a shield case 37, and the negative electrode of a DC power source 40 is connected to this by passing through the shield case 37.

In such a conventional device, after the pressure inside the plasma generation chamber 31 and the sample chamber 33 is reduced to a predetermined value, gas is supplied to these through a gas supply system (not shown), and the microscopy chamber 33 is Plasma generation chamber 31 through wave tube 32
Microwaves are introduced into the plasma generation chamber 31, and a magnetic field is generated by energizing the excitation coil 34 to establish an electron cyclotron resonance condition within the plasma generation chamber 31 to generate plasma. Plasma is introduced into the sample chamber 33 through the plasma extraction window 31c as shown in FIG. 5 by a diverging magnetic field formed by the excitation coil 34.

FIG. 5' is an explanatory diagram of the lines of magnetic force of the divergent magnetic field, and the ions in the plasma are accelerated by the negative voltage applied to the target 36 when they are introduced into the sample chamber 33 through the plasma extraction window 31c. Then it entered the surface of Kude 7 and 6, giving it a shock and causing Kude.

Atoms of the target 36 are spattered and ejected into the plasma flow, and are incident on the sample substrate S as they are, or with some of them having lost electrons in the plasma, to form a film.

Further, the diverging magnetic field is shaped by a ring member 38 made of soft iron or a magnet in a ring shape, and magnetron discharge plasma is generated on the surface of the target 36.

[Problem to be solved by the invention]

However, in such a conventional device, since the target 36 is formed in a cylindrical or conical shape as described above, there are many difficulties in terms of cost and manufacturing technology.

For example, A7! When Δl is used as the target 36, cooling of the target 36 is essential because Δl has a low melting point. Therefore, providing a cooling channel in the target 36 requires the use of more expensive materials than necessary, which is disadvantageous in terms of cost.・Also, when adhering or welding a cylindrical Kuget to the inner surface of a cooling cylinder made of another material, it is necessary to consider the coefficient of thermal expansion of the amount of material, so the target 36
Materials are limited. For example, a substance with a small coefficient of thermal expansion is called Coude.

36, it is impossible to achieve thermal contact by adhering, brazing, shrink fitting, cold shrinking, or other fixing means to the cylindrical inner surface of a material with a large coefficient of thermal expansion.

Furthermore, when it is necessary to frequently replace the target for experiments or the like, or when the target 36 is severely worn out, replacing the target with the conventional spackle apparatus is time consuming and troublesome.

On the other hand, when generating magnetron discharge on the surface of the target 36, it is necessary to form a strong magnetic field.

Therefore, when shaping the magnetic field using a magnetic material such as soft iron, it is necessary to place it directly below the surface of the target 36, but when cooling channels are required, it is not possible to place the magnetic material directly below the surface of the target 36. When a ring-shaped permanent magnet, instead of a magnetic material, is brought into close contact with the outer periphery of the target 36 in order to form a strong magnetic field, there are difficulties in manufacturing and assembling the magnet.

The present invention has been made in view of the above circumstances, and by making the cuguette and the holding means for holding it into a flat plate shape and making it divisible, it is possible to easily replace the cuguette and manufacture the cuguette and the holding means. The objective is to not only limit the material of the target but also to equip the holding means with a permanent magnet to form a strong magnetic field while cooling, to easily generate magnetron discharge on the target surface, and to improve sputtering efficiency. .

[Means to solve the problem]

The sputtering apparatus according to the present invention uses plasma to sputter a target disposed between a sample stage on which a sample substrate is placed and a plasma outlet for drawing out plasma, thereby depositing a thin film on the sample substrate. A sputtering apparatus for depositing is characterized by comprising a flat target and a holding means in the form of a polygonal tube that holds the target and can be divided into a plurality of flat parts, and the holding means has the following features: It is characterized by having permanent magnets on a plurality of flat parts.

[Effect]

In the present invention, the target is in the form of a flat plate, and the holding means for holding it is composed of a polygonal tube that can be divided into flat parts that match the target. The holding means can be manufactured easily, the material of the target is not limited, and
Since a permanent magnet is provided on the flat surface of the holding means, magnetron discharge can be easily generated.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof.

FIG. 1 is a schematic longitudinal section of a sputtering apparatus according to the present invention (referred to as the present invention apparatus), in which 1 is a plasma generation chamber, 2 is a microwave waveguide, 3 is a sample chamber, 4 is an excitation coil, S indicates a sample substrate.

The plasma generation chamber 1 is configured to function as a microwave cavity resonator, and has a microwave introduction window 1b sealed with quartz glass 1a in the center of its upper wall, and a plasma drawer in the center of its lower wall. One end of the microwave waveguide 2 is connected to the microwave introduction window 1b, and a sample chamber 3 is provided facing the plasma extraction window 1c. An excitation coil 4 is disposed so as to surround the chamber 1 and one end of the microwave waveguide 2 connected thereto.

The other end of the microwave waveguide 2 is connected to a high frequency oscillator (not shown), and microwaves emitted from the high frequency oscillator are introduced into the plasma generation chamber 1.

The excitation coil 4 is connected to a DC power source (not shown), and forms a magnetic field that satisfies electron cyclotron resonance conditions in the plasma generation chamber 1, and also forms a diverging magnetic field whose magnetic flux density decreases toward the sample chamber 3 side. That's how it is.

A sample stage 5 is disposed in the sample chamber 3 at a position facing the plasma extraction window 1c, and a sample substrate S is placed on this stage.

In addition, the sample chamber 3 of the plasma extraction window 1c is located inside the sample chamber 3.
A sputtering target 6 is placed facing the periphery of the side opening.
The square cylindrical holding means 9 holding the plasma extraction window 1c
are arranged concentrically.

FIG. 2 is an enlarged cross-sectional view in a plane perpendicular to the central axis showing the structure of the holding means and the target, and FIG. 3 is a cross-sectional view taken along the line mm in FIG. 2.

The holding means 9 is placed in a rectangular shield case 7 with a C-shaped cross section, with the four corners insulated by insulating materials 7L71, excluding the inner peripheral surface.
The upper and lower end surfaces and the outer peripheral surface are covered and held. Further, the holding means 9 includes first holding parts 91a and 91 arranged oppositely.
a and second holding parts 91b, 91b, and further includes a first
The holding parts 91a, 91a have a concave portion formed in the center of one side, and a flat plate-shaped tarquent 6a on the other side.

rectangular first support parts 93a, 93a, which are fixed by suitable fixing means such as brazing or adhesive, four parts and a cooling water channel 96, and the four parts are opposed to the recessed parts of the first support parts 93a, 93a. A rectangular first cooling section 92a is installed in a vertical manner.

92a. Also, the second holding parts 91b, 9
1b has a convex portion formed on one surface thereof, and flat plate-shaped targets 6b, 6b are fixed thereto by the fixing means, and rectangular second support portions 93b, 93b having a concave portion formed on the other surface;
It is provided with a recessed part and a cooling water channel 96, and the four parts are connected to the second support part 9.
3b and 93b, the second cooling portions 92b and 92b are rectangular in shape and are mounted opposite to each other in the recessed portions of the cooling portions 3b and 93b. Four pairs of rectangular parallelepiped permanent magnets 8a and 8b are arranged in four rectangular spaces formed by opposing recesses.

Further, the permanent magnets 8a and 8b are provided with the inside of the permanent magnet 8a as the S pole and the inside of the permanent magnet 8b as the N pole (the third
(see figure). The holding means 9 includes two first holding parts 91a, 91a and two second holding parts 91b at the positions indicated by thick lines.
It can be easily divided into four parts consisting of 91b and 91b.

On the other hand, an electrode 94 connected to a DC or RF power source (not shown) is provided on one side of the holding means 9, and a cooling water inlet is provided at the center thereof. A cooling water outlet fitting 95 is provided on the other side, and is piped to the outside of the sample chamber 3 via a piping connector 97.

Furthermore, the mounting surfaces of the aforementioned metal fittings, electrodes, and each member are all sealed with Murakami members such as O-rings.

In the apparatus of the present invention, after the plasma generation chamber 1 and the sample chamber 3 are evacuated and the pressure is reduced to a predetermined value, gas (for example, Ar gas) is supplied into the plasma generation chamber 1 from a gas supply system (not shown). While introducing microwaves into the plasma generation chamber 1 through the microwave waveguide 2, a magnetic field is formed by the excitation coil 4, and electron cyclotron resonance conditions are established in the plasma generation chamber 1 to generate Ar, etc. A plasma is generated by sputtering atoms and molecules, and is introduced into the sample chamber 3 through the plasma extraction window 1c by a divergent magnetic field formed by the excitation coil 4.

Further, a negative voltage from a DC power source (not shown) or a negative voltage due to the self-bias effect of an RF power source is applied to the target 6 via an electrode 94, and the ions are attracted to this and accelerated to the surface of the target sensor h6. collide with each other and spatter.

The sputtered atoms ejected from the target 6 remain as they are, and some of them lose electrons in the surrounding plasma and are ionized, guided to the surface of the sample substrate S, and attached thereto to form a film. Further, when a reactive gas such as 02 is simultaneously introduced into a plasma chamber or a reaction chamber together with a sputtering gas, a reactive sputtered film such as an oxide film is formed in the case of the 02 gas.

Further, the target 6 heated by the plasma is placed inside the electrode 94 provided on the holding means 9, in the cooling channels 96.
and the cooling water outlet fitting 95 are cooled by the cooling water flowing in this order in the direction shown by the arrow.

On the other hand, as shown in FIG. 3, magnetic lines of force shown by arrows are formed upward near the surface of the target 6 due to the polarity of the upper and lower pair of magnets 8a and 8b, and magnetron discharge plasma is generated in the space surrounded by the lines of magnetic force and the target 6. is formed, improving sputtering efficiency.

In addition, in this example, the holding means is a square cylinder,
Although the structure is such that it can be divided into four parts, the present invention is not limited to this, and the holding means may have any shape as long as it is a polygonal cylinder having a flat part.

Furthermore, in this embodiment, a pair of upper and lower permanent magnets are arranged with polarity such that the lines of magnetic force are directed upward; however, the present invention is not limited to this, and the direction of the lines of magnetic force can be changed to cause magnetron discharge near the target surface. Any direction is fine if possible.

〔Effect of the invention〕

As described in detail above, according to the sputtering apparatus according to the present invention, the target is made into a flat plate, and the holding means for holding it is constituted by a polygonal tube that can be divided into flat parts, so that the target can be easily replaced and The production of the couget and the holding means is easy, and the material of the target is not limited, and since the holding means is equipped with a cooled permanent magnet, magnetron discharge plasma is formed on the target surface by a strong magnetic field, increasing sputtering efficiency. It has an equivalent effect of improving the

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view of a sputtering apparatus according to the present invention, FIG. 2 is an enlarged sectional view showing the structure of the holding means and the cuget, FIG. 3 is a sectional view taken along the line ■-■ in FIG. The figure is a schematic longitudinal sectional view of a conventional ECRC sputtering apparatus, and FIG. 5 is an explanatory diagram of magnetic lines of force of a divergent magnetic field. 1... Plasma generation chamber 1c... Plasma drawer window 3
...Sample chamber 5...Sample stage 6...Target soto 9
...Holding means 8a, 8b...Permanent magnet S...Sample substrate patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Fig. 1 31b 32 Rod 4 Fig. 5

Claims (1)

[Claims] 1. Sputtering a thin film onto the sample substrate by sputtering a target disposed between a sample stage on which a sample substrate is placed and a plasma extraction port from which plasma is extracted. What is claimed is: 1. A sputtering device for depositing, comprising: a target in the form of a flat plate; and a holding means in the form of a polygonal tube that holds the target and can be divided into a plurality of flat parts. 2. The sputtering apparatus according to claim 1, wherein the holding means includes permanent magnets on a plurality of flat surfaces thereof.