JPH02115366A - Sputtering device - Google Patents

Abstract

PURPOSE:To prevent cross-contamination between targets by arranging cathodes using nonmetal targets and cathodes using metal targets in series at intervals in one chamber. CONSTITUTION:In this sputtering device for forming a multilayered film, plural cathodes are arranged in series in one chamber and a holder or tray 4 supporting a substrate on which a film is formed by sputtering is moved in one direction. The cathodes are cathodes 8 using nonmetal targets such as carbon or ceramic targets and cathodes 6, 7 using metal targets. The interval between the centers of the targets is made >=4 times as large as the effective width of the exposed parts of the nonmetal targets.

Description

Detailed Description of the Invention Field of Application The present invention relates to an improvement of a sputtering apparatus for forming a multilayer film having two or more cathodes. The present invention relates to a sputtering apparatus that can prevent cross-contamination between cathodes and form a multilayer film with excellent properties.

BACKGROUND ART In recent years, in the production of semiconductor devices and electronic components, in particular, in order to form a required thin film on the surface or to form a multilayer film,
Sputtering equipment has come into widespread use.

Multilayer films are often used in such electronic devices, but in this case, films are formed continuously in a vacuum without being exposed to the atmosphere between the formation of one film and the formation of the next film. There are many cases where it is necessary to do so.

When forming a multilayer film continuously in a vacuum, a sputtering device having two or more types of cathodes, for example, a third cathode, is used.
As shown in the figure, two rooms are evacuated using one vacuum pump.
A sputtering apparatus for forming a multilayer film is used in which multiple cathodes are arranged in series and a holder or tray on which a substrate to be sputtered is placed moves in the same direction.

However, when attaching two or more types of targets to two or more types of cathodes to form a multilayer film, cross-contamination between the targets or adhesion to the non-erosion area of a flat magnetron target or around the target may occur. There is a risk that the multilayer film will contain impurities and defects such as pinholes may occur due to peeling of the film or particles, which may adhere to the substrate during film formation.

As a measure to prevent cross-contamination, measures such as covering the target with an adhesion prevention plate called a chimney are taken.

However, chimneys have a problem in that they are insufficient for fine particles of several vm or less, which are likely to occur when targets made of carbon or various ceramics are used.

Therefore, a method has been proposed in which only a cathode using a target that is likely to generate fine particles is attached to a vacuum chamber separate from other cathodes.

This multi-chamber sputtering equipment requires measures such as installing gate valves between chambers and separate exhaust devices, making the equipment complex and time-consuming, and the cost is extremely high. was there.

Purpose of the Invention In view of the above-mentioned conventional problems, the present invention aims to prevent cross-contamination between targets in a sputtering apparatus, and further prevent particles of target material from adhering to a substrate during film formation, and in particular to prevent particles of target material from adhering to a substrate during film formation. In a sputtering apparatus that continuously forms a film and a film of carbon, ceramics, etc., it is possible to prevent the particles of carbon, l or ceramics, etc. from adhering in or under the metal film, and the structure is simple. The purpose is to provide a low-cost sputtering device.

Summary of the invention This invention arranges two or more types of cathodes in series in one chamber,
In a multilayer film forming sputtering device in which the holder or tray on which the substrate to be sputtered is placed moves in the same direction, the distance between the centers of the targets is between the cathode that uses a non-metal target such as carbon or ceramics, and the cathode that uses a metal target. A sputtering apparatus characterized in that the distance is at least four times the effective exposure width of the non-metal target, and in the above configuration, the width in the moving direction of the holder or tray is equal to or less than the distance between both ends of the cathode. A sputtering apparatus characterized in that the above-mentioned non-metal target and the metal target are further provided with an opening/closing damper that forms a gap through which the tray can pass when closed. It is a device.

Structure of the Invention In other words, the present invention provides two
In a sputtering apparatus having more than one cathode, the center distance between the cathodes is at least 4 times, preferably at least 5 times, the maximum width (diameter in the case of a circular target) of the target as viewed in the direction in which the cathodes are arranged, and The above objective can be achieved by making the length of the substrate boulder or tray holding the substrate boulder or tray in the cathode arrangement direction less than or equal to the distance between both ends of the cathodes, and at least one of the two or more types of targets mentioned above. This is particularly effective when the seed is carbon or ceramic.

In this invention, in order to obtain the cross-contamination prevention effect, it is necessary that the distance between the centers of the non-metallic target and the metal target in adjacent cathodes be at least four times the effective exposed width of the non-metallic target, but preferably It is more than 5 times. However, even if the distance between the target centers is increased unnecessarily, the effect of this invention cannot be sufficiently enhanced, and problems such as the required capacity of the vacuum pump will become larger and the cost will increase significantly. desirable.

Further, in the present invention, the width of the holder or tray in the moving direction is equal to or less than the distance between both ends of the cathode.
This is to prevent the electric field distribution from changing when the tray passes, causing the plasma of the non-metal target to spread to adjacent targets, and to prevent generated dust from flowing along the tray to the metal target surface due to the potential difference or gas flow.

Furthermore, in order to effectively carry out the present invention, an adhesion prevention plate having a gap large enough to allow the tray to pass, so as to partition between the cathode on which the metal target is placed and the cathode on which the non-metal target is placed; It is desirable to provide a so-called slit portion.

However, if the slit portion is of a fixed type, the resistance to evacuation will be large and the ultimate degree of vacuum will be poor.

If the gap is made larger, the effect of preventing cross-contamination and scattering of dust particles, which is the objective of the present invention, will be reduced.

Therefore, by making this slit part a movable damper, the opening is made large during non-sputtering to lower the exhaust resistance and make it easier to create a vacuum, and during sputtering it is closed to leave a gap large enough for the tray to pass through. This invention can be implemented more effectively.

The movable damper may be made of the same material as the parts normally used inside the sputtering apparatus, such as AI or stainless steel. Further, the opening/closing mechanism may be a rotary type, a sliding type, or other known mechanism, and preferably has a structure that does not generate dust during operation.

Also, it is desirable that the gap when the damper is closed is as narrow as possible, but it is necessary that it does not come into contact with the tray.
In practice, it is desirable to adjust the gap size appropriately, taking into consideration the material of the target, sputtering conditions, etc.

Based on the Drawings (Disclosure of the Invention) FIGS. 1 and 2 are schematic explanatory diagrams showing the structure of a sputtering apparatus according to the present invention.

Configuration 1 The apparatus shown in FIG. 1 is a widely used sputtering apparatus for small-volume production of magnetic disks, which has the configuration of the present invention. Here, an example will be described in which Cr, CoNiCr, and carbon films are formed on the substrate in this order.

In the main body of the apparatus, a disk substrate loading/unloading chamber (1) and a sputtering chamber (2) are separated by a gate valve (3).

In the loading/unloading room (1), the substrate is placed on the tray (4) in a predetermined position, and after evacuation, the tray is placed in the heater (5).
move to position.

The substrate placed on the tray (4) is heated to a predetermined temperature by a heater (5), and then moved to each cathode position.

When the gas pressure is adjusted to a predetermined value of several mTorr to several tens of mTorr, a Cr cathode (
6), CoNiCr with CoNiCr target mounted
When the tray (4) passes in front of each of the cathodes (7), a predetermined voltage is applied to the cathodes (6×7), and each metal film is sputtered.

After the tray (4) has completely passed in front of the cathode (7), the tray (4) is moved to the left to the heater (5) position, and then the gas pressure is changed to a value suitable for forming a carbon film.

Then, by applying a predetermined voltage to the carbon cathode (8) on which the carbon target is placed, carbon is sputtered, and the tray (4) is moved to pass in front of the cathode (8), thereby sputtering the metal. A carbon film is formed on the film to a predetermined thickness.

Further, the distance between the centers of the targets of the CoNiCr cathode (7) and the carbon cathode (8) is set to be at least four times the effective exposure width in the arrangement direction of the targets, and The width of the movement method is set to be smaller than the distance between the end faces of the cathode (7×8).

Further, a damper (10) is provided between the cathodes (7×8) having the required dimensions to partition the cathodes (7×8).
Here, a pair of rotary dampers are arranged so as to sandwich the tray (4) above and below in the figure, so that a required slit is formed when the rotary damper (10) is closed.

This damper (10) further enhances the cross-contamination prevention effect.

Further, it is more effective to arrange the vacuum exhaust port of the sputtering chamber (2) on the right side in the figure in order to prevent generated non-metal target particles from being mixed into the metal film.

In addition, the code|symbol 9 in a figure is a chimney.

Configuration 2 The device shown in FIG. 2 has basically the same structure as the device shown in FIG.
It is installed at the right end of the figure farthest from the extraction chamber (1), so the cathode arrangement is switched from the right side to the Cr cathode (6), the CoNiCr cathode (7), and the carbon cathode (8). Things are different.

However, the distance between the centers of the targets of the CoNiCr cathode (7) and the carbon cathode (8) is set to be more than four times the effective exposure width in the array direction of the targets, and furthermore, The width of the movement method is set smaller than the distance between the respective end faces of the cathodes (7) and (8), and the damper (10) can be installed, as in the apparatus shown in FIG.

The film forming procedure is as follows. The substrate and tray (4) are heated with a heater (5), and then Cr and CoNiCr are deposited while moving the tray (4) to the left until the tray (4) completely passes in front of the cathode (7). Tray (4) is stopped when it passes through.

Next, the gas pressure is changed to discharge the carbon cathode (8), and the tray (4) is moved again to form a carbon film.

Embodiments Example 1 Using the sputtering apparatus according to the present invention having the configuration shown in FIG. 2 described above, and the conventional apparatus shown in FIG. 3, which has basically the same configuration as that in FIG.
In addition to setting the distance between the cathodes as shown below, other conditions such as Ar gas pressure, electric power, tray movement speed, etc. were the same for both the apparatus of the present invention and the conventional apparatus, and test pieces were manufactured under the following conditions.

Distance between the centers of the cathode (7X8) of the device of the present invention; 60 island plate, which is more than 4 times the exposed effective width (126mm) of the carbon target, cathode dimensions; 479mm Cliff tray width (440mm) Conventional device Distance between target centers in the arrangement direction of each cathode; 35
0mm, exposed effective width of carbon target; 126mm, distance between cathode end faces; 224mm, width of tray; 44
0mm.

Cathode dimensions; 126mm width x 456mm length x 6mm thickness test piece 1
Substrate heating 160℃ x 20 minutes Cr 1500A
, CoNiCr 700A film-forming test piece 2 Substrate heating 160″C x 20 minutes Cr
1500A CoNiCr 700A C400A Film forming test piece 3 Substrate heating 160°C x 20 minutes Cr
1,500 people CoNiCr 700A Each film deposition apparatus was used to continuously manufacture the above test pieces 1.2.3, and each Si wafer (less than 2 pieces/side) that had been tested for the number of dust of 0.8 pm or more was used as a substrate for film formation. ) was used to compare the increase in dust. The results are shown in Table 1.

Table 1 As is clear from Table 1, in the case of test specimen 1 with a clean inside of the device, the number of both cases is less than a few tens of pieces per side, and when a carbon film is sputtered, the number increases to more than 1000 pieces per side. .

However, in the case of test piece 3, in which only a metal film is deposited again, the device of the present invention has 30 pieces on one side, which is the same level as test piece 1, but the conventional device has 621 pieces on one side. It can be seen that it has increased tremendously.

Next, when we randomly selected 10 particulate defects on the wafer used to manufacture test piece 3 using the comparison device and analyzed them using an X-ray microanalyzer, C was detected in 9 of them. Ta. These defects are considered to be carbon dust generated within the sputtering device.

The above test results prove that in conventional sputtering equipment, a large amount of carbon dust generated within the equipment adheres to the sputtered metal film and is the main cause of defects.

On the other hand, the sputtering apparatus according to the present invention can almost prevent carbon particles from entering the metal film.

Example 2 Using the device of the present invention shown in FIG. 2 and the conventional device shown in FIG. 3, Cr 1500A, CoNi, etc.
700 Cr layers and 400 carbon protective layers were formed.

After reaching vacuum, the argon gas pressure, substrate temperature, and power input during sputtering were the same for the same apparatus.

The obtained magnetic disk is coated with Al2O3-TiC using a lubricant.
When subjected to a C8S test using a magnetic head manufactured by the present invention, no abnormality was observed in the head or disk even after 10,000 tests on the disk manufactured using the device of the present invention, but the disk manufactured using the conventional device. A head crash occurred at the 266th time.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic explanatory diagrams showing the structure of a sputtering apparatus according to the present invention. FIG. 3 is a schematic explanatory diagram showing the configuration of a conventional sputtering apparatus. 1...Preparation/unloading room, 2...Sputtering room, 3...
・Gate valve, 4...Tray, 5...Heater 6
... Cathode for Cr, 7... Cathode for CoNiCr, 8... Cathode for carbon, 9... Chimney 10
...Dunbar

Claims (1)

[Claims] 1. A sputtering apparatus for forming a multilayer film in which two or more cathodes are arranged in series in one chamber and a holder or tray on which a substrate to be sputtered is placed moves in the same direction. A sputtering apparatus characterized in that the distance between the centers of the cathodes using a metal target and the cathode using a metal target is at least four times the exposed effective width of the non-metal target. 2. The sputtering apparatus according to claim 1, wherein the width of the holder or the tray in the moving direction is equal to or less than the distance between both ends of the cathode. 3. The sputtering apparatus according to claim 1 or 2, further comprising an opening/closing damper that forms a gap through which the tray can pass when closed, between the non-metal target and the metal target.