JPH10204629A - Sputtering equipment - Google Patents

Abstract

(57) [PROBLEMS] To improve a film thickness distribution and film quality due to potential fluctuations of a substrate, a tray, and the like in a sputtering apparatus used for film formation on a substrate. A substrate and a tray 2 on which a film is to be formed are positioned facing a target 1, and the substrate and the tray 2 move parallel to the target surface, that is, as shown by arrows in the figure (from left to right). I do. A shielding plate 3 having a desired opening is provided between the target 1, the substrate and the tray 2 so as to face the target. This suppresses sputtered particles from the oblique direction on the substrate, improves the uniformity, adhesion and film quality, and improves the change in distribution due to changes in erosion depth. A uniform film thickness distribution provides good adhesion and good film quality. It is obtained over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus.

[0002]

2. Description of the Related Art Conventionally, in a sputtering apparatus, magnetron sputtering in which a permanent magnet is provided below a target and a magnetic field is applied to the target surface is used in order to suppress a rise in target temperature and increase a sputtering speed. In this magnetron sputtering, the uniformity of the sputtered film was determined by the distribution of the magnetic field intensity on the target surface.

For this reason, the thickness distribution of the sputtered film has been made uniform by adjusting the distribution of the magnetic field intensity. That is, in order to improve the thickness of the sputtered film at the end portion of the target perpendicular to the movement of the substrate and the tray (the sheet resistance is increased), the magnetic field intensity at the end portion in the long side direction of the target is reduced. By increasing the strength, the sputtered film is made uniform.

[0004]

However, in such a method, it is difficult to adjust a delicate balance of the magnetic field distribution particularly at the end and the center. Further, in the magnetron sputtering, a groove formed according to a magnetic field by sputtering, that is, an erosion groove is formed, and the thickness distribution of the formed film changes due to a change in a direction in which sputter particles fly out. However, it is very difficult to change the magnetic field intensity distribution with this change because of the permanent magnet, so that the film thickness distribution could not be kept uniform over a long period of time.

Further, in the case of an in-line type or a carousel type in which a tray on which a substrate on which a film is to be deposited is mounted passes over a target, the tray is in contact with a vacuum apparatus housing and is always at a ground potential. I have. However, when a conductive material such as Al or a semiconductor such as ITO (compound of In oxide and Sn oxide) is deposited on an insulating substrate such as glass by a combination of the substrate and the adherend, the substrate is exposed to plasma. Exposure or charging by sputtered particles creates a potential that changes due to deposition of the film, which in turn affects the plasma or changes the potential of the target, which results in a film that is particularly in the direction of tray movement. The thickness was uneven.

Further, when the tray is not directly above the target, sputtered particles adhere from an oblique direction, so that the film quality such as deterioration of film adhesion and crystallinity deteriorates, and film characteristics in reliability such as heat resistance and humidity resistance tests. It was a cause of deterioration. This phenomenon is important in the initial stage of film formation, and this phenomenon cannot be avoided in the case of a tray moving type apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a uniform distribution in the direction of movement of a tray and a direction perpendicular thereto, and to obtain a good film quality.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to install a shielding plate having a desired opening facing a target in a sputtering apparatus. This makes it possible to obtain a uniform distribution in the direction in which the film is formed and to obtain a good film quality.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a shielding plate having a desired opening facing a target is provided.
This is a sputtering apparatus installed between a target and a substrate on which a film is to be deposited, and passes a desired amount of sputtered particles from the target in accordance with the size of the opening of the shielding plate and deposits the sputtered particles on the substrate. The opening has the effect of adjusting and uniforming the distribution of the film thickness depending on the location.

According to the invention described in claim 2 of the present invention, the size of the opening of the shielding plate differs depending on the location in the direction perpendicular to the direction in which the substrate and the tray move, and the width of the central portion is substantially equal to the width of the target. And the width of both ends is larger than the width of the central part, and allows a desired amount of sputtered film particles from the target to pass according to the opening of the shielding plate. It is adjusted as desired. That is, the opening width is reduced in a portion where the sputtered particles are large, and conversely, the opening width is increased in a portion where the sputtered particles are small, so that the amount of the sputtered particles in the long side direction of the target is made uniform.

Further, by making the width of the central portion of the target in the direction perpendicular to the direction in which the substrate and the tray move substantially equal to the width of the target, it is possible to prevent the sputter particles from adhering from an oblique direction which deteriorates the adhesive force, and to prevent erosion. It is intended to minimize a decrease in the deposition rate while suppressing a change in distribution due to a change in depth. In addition, by increasing the width of the opening at both ends, a decrease in the film thickness in a portion where the magnetic field strength is small at both ends can be compensated, and a region with a uniform film thickness can be enlarged. Thereby, the distribution of sputter particles in the direction of the long side of the target, that is, the film thickness distribution can be adjusted as desired.

According to a third aspect of the present invention, the size of the opening of the shielding plate in a direction perpendicular to the direction in which the substrate and the tray move is made smaller than the center of the target erosion. Since the high-density plasma is always shielded and the shielding plate is located inside the erosion center, the plasma has a function of suppressing the fluctuation of the plasma due to the movement of the substrate and the tray and stabilizing the substrate potential.

Thus, even when a large number of trays continuously pass over the target as in an in-line type or repeatedly pass over the target as in a carousel type, the tray and the substrate have an effect of stably maintaining the potential of the target and the substrate. doing. Therefore, a uniform film thickness distribution can be obtained not only within the substrate but also between the substrates in the moving direction of the substrate and the tray.

According to a fourth aspect of the present invention, the shielding plate is set to a ground potential, and the shielding plate has an effect of releasing charges due to plasma or sputtered particles to the ground, that is, to the apparatus housing. Thus, the potential of the substrate and the tray is stabilized with respect to the ground potential, and a uniform film thickness distribution can be obtained.

According to a fifth aspect of the present invention, a voltage is applied between the shield plate and the target. In particular, by applying a negative voltage to the shield plate, charged particles due to plasma or sputtered particles are applied by the shield plate. Has the effect of more actively attracting and eliminating. By this action, the potential fluctuating with the deposition of the film can be more positively stabilized, so that the fluctuation of the potential due to the movement of the substrate and the tray is suppressed, and a uniform film thickness distribution can be obtained. It is.

According to a sixth aspect of the present invention, the outer peripheral portion of the shielding plate is made closer to the target from the periphery of the opening, and sputtered particles sputtered from the target and projected obliquely are attached to the substrate by the outer peripheral portion of the shielding plate. Has the effect of reliably preventing the occurrence of Thus, it is possible to prevent sputter particles from adhering obliquely at a large angle in the initial stage of film formation, which has the greatest effect on the film quality.

Such sputtered particles adhered obliquely at a large angle not only deteriorate the crystallinity, but also deteriorate the adhesion and cause peeling of the film. Therefore, only the opening as in the present invention is used. When the film can be formed by sputtered particles, not only the adhesion of the film is improved and good film quality is obtained, but also a uniform film whose film thickness distribution is determined only by the shape of the opening can be obtained.

According to a seventh aspect of the present invention, there is provided the sputtering apparatus according to any one of the first to sixth aspects, wherein the substrate on which the film is deposited is moved past a target. The present invention is applicable to a sputtering apparatus of a type in which a film is formed by moving a substrate and a tray over a target like a mold.

Here, in the case of the system in which the substrate rotates or revolves on the target, the substrate does not fluctuate in potential since it is always located on the target and exposed to the plasma. However, in the case of an apparatus in which a substrate and a tray pass over a target to form a film, when the substrate and the tray pass over the target and form a film, the potential of the substrate and the target greatly fluctuates because the substrate and the tray cross a plasma. I do.

Therefore, the application of the inventions of claims 1 to 6 to a sputtering apparatus for forming a film by moving and passing a substrate and a tray over a target is effective in stabilizing the potential and effectively. Is utilized to the maximum and uniform film thickness distribution and good film quality can be obtained.

According to an eighth aspect of the present invention, at least the sputtering surface of the substrate is an insulator, and the adherend is a semiconductor or a conductor. When the sputtered surface of the substrate, that is, the film forming surface is an insulator, the charge charged by the sputtered particles or plasma is less likely to conduct than a conductive material such as a metal, and a conductive or semiconductor film is formed on the insulating material. In this case, the charge transfer between the region where the film is formed and the region where the film is not formed is different, and the potential distribution in the substrate causes the potential of the substrate and the target to become unstable.

Accordingly, a conductive material such as a metal such as Al or Cu, an ITO or Si When a semiconductor such as that described above is formed, the effect of stabilizing the potential can be made effective by installing a shielding plate having the various desired openings. As a result, a uniform film thickness distribution and good film quality can be formed, and the effect can be maximized.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows a schematic cross section of a main portion around a target of an in-line type sputtering apparatus. Substrate and tray 2 on which film is to be formed facing target 1
The substrate and the tray 2 move parallel to the target surface, that is, as shown by the arrow in the figure (from left to right). A shielding plate 3 having a desired opening is provided between the target 1, the substrate and the tray 2 so as to face the target 1. The shielding plate 3 employs a metal material such as stainless steel (SUS) from the viewpoint of electrical conductivity. A SUS shield plate 5 is provided around the target 1. The shield plate 5 is provided in order to prevent abnormal discharge due to generation of plasma between the periphery and the side of the target and the device housing, and has the same potential as the device housing, that is, the ground potential.

Here, the shielding plate 3 is fixed by a support rod 4 attached to the apparatus housing. Therefore, if a metal material such as SUS is used for the support rod 4, the shielding plate 3 can be easily set to the ground potential. Sputtered particles 6 protrude from the target 1, and the direction in which the sputtered particles 6 protrude changes depending on the depth of the erosion.

FIG. 2 is a schematic plan view of the shielding plate 3 as viewed from the substrate and the tray 2 side. The size of the target 1 is 150 mm in width in the direction of movement of the substrate and the tray 2, and 500 mm in the vertical direction. It is located beyond the plate 3. The erosion is dumbbell-shaped, and has a shape in which both sides of the target longitudinally swell in a direction perpendicular to the direction of movement of the tray 2, which prevents the spatter rate from decreasing on both sides and the back of the target 1. From the processing problems of the permanent magnets.

The opening 7 in the shielding plate 3 is
The width 9a at the center of the opening 7 of the shielding plate 3 and the width 9b at both ends thereof are different from the reciprocal of the film thickness distribution when the shielding plate 3 is not provided. It has been changed to become.

For example, the width 9a at the center is 160 mm and the width 9b at both ends is 190 mm, and the width at both ends is larger than that at the center. Further, the width 9a160mm at the center is substantially the same as the width 150mm of the target 1, and is slightly larger. As a result, the high-density plasma of the target 1 is partially shielded, thereby significantly reducing the charging of the substrate and the tray 2 by the plasma. This stabilizes the potential of the substrate, and the sputtered particles 6 are repelled by the electric field of the sputtered particles 6 due to the fluctuation of the substrate potential.
Can be prevented from fluctuating.

However, in order to avoid a decrease in the film forming rate due to extremely suppressing the passage of the sputtered particles 6, the target is located outside the center 10 of the erosion of the target. Thereby, the sputtered particles 6 from the oblique direction are
And the change in distribution due to changes in uniformity, adhesion, film quality, and erosion depth can be improved.

On the other hand, high-density plasma is always shielded irrespective of the movement of the substrate and the tray 2, and the fluctuation of the plasma due to the movement of the substrate and the tray 2 is suppressed by the shield plate 3 being inside the center 10 of the erosion. In addition, in order to stabilize the substrate potential, the opening 7 of the shielding plate 3 in a direction orthogonal to the direction in which the substrate and the tray 2 move.
, Ie, the size of the opening 7 in the direction perpendicular to 9a and 9b, is smaller than the center 10 of the target erosion and is 380 mm.

Regarding the case where the above-described shielding plate of the present invention was adopted and the case where it was not used (conventional method), ITO was formed on a substrate by DC magnetron sputtering using soda lime glass, and the distribution was compared. The distribution was evaluated by measuring the sheet resistance. Here, the sheet resistance distribution reflects the film thickness distribution, and is adopted as an evaluation means because it can be easily measured with high precision electrically. FIG. 3 shows the distribution of the sheet resistance in the direction perpendicular to the movement of the substrate and the tray. The sheet resistance is indicated by the rate of change standardized at the center.

It can be seen that when the present invention is employed, the uniform area is wider than in the conventional method. FIG. 4 shows the distribution of the substrate and the tray in the moving direction. The vertical axis indicates the difference from the average sheet resistance normalized by the average sheet resistance. It can be seen that the distribution is more uniform when the present invention is employed than in the conventional method. That is, by the shielding plate of the present invention,
A uniform distribution can be obtained on the front surface of the substrate.

Although the DC magnetron has been described here, the shielding plate of the present invention can also be applied to an RF magnetron or a simple sputtering apparatus in which no permanent magnet is provided below the target. Further, it is needless to say that the shape and size of the opening of the shielding plate need to be appropriate depending on the size and shape of the target, the magnetic field strength of the magnet provided below the target, and the like.

(Embodiment 2) FIG. 5 shows a structure for electrically insulating the shield plate 3 from the housing of the apparatus and enabling voltage application to the shield plate 3. The shielding plate 3 is supported by a support rod 4 attached to the apparatus housing similarly to the shielding plate 5. Here, by using an insulating material such as quartz glass or alumina as a material of the support rod 4, the shielding plate 3 can be easily electrically insulated from the apparatus housing.

However, in this state, a conductive material or a semiconductor film adheres by sputtering, so that the film becomes electrically conductive. In order to prevent this and maintain the electrical insulation permanently, the protective cover 11 from the shield plate 3 side, the shield plate 5 and the protective cover 12 from the housing side are installed. As shown in the figure, the protective covers 11 and 12 overlap with each other with an interval therebetween to prevent the sputter film from adhering.

Here, the shield plate 3 is electrically connected to the shield plate 3 by screwing, welding, or contact with a clip or the like, and a voltage can be applied to the shielding plate 3 by a lead wire coated with insulation. By setting the applied voltage to an appropriate value, the effect of the shielding plate 3 can be maximized.

(Embodiment 3) FIG. 6 shows a shielding plate 3 for more reliably preventing sputtered particles 14 from an oblique direction with respect to a substrate. An inclined eave 13 is provided by bringing the outer peripheral portion of the shielding plate 3 closer to the target than the periphery of the opening. Here, the direction of the sputtered particles 14 from the oblique direction is changed by the collision of the sputtered particles 6 with each other or with a sputter gas or the like.

These sputtered particles 14 have a small energy, and when adhered to a substrate, not only have poor adhesion but also have poor crystallinity, but they have an important effect on the film quality on the substrate. , Which are most likely to be removed during the initial stage of film formation. Accordingly, by providing the eaves 13 on the outer peripheral portion of the shielding plate 3, sputter particles can be reliably removed from oblique directions, and the film quality can be improved.

[0038]

As described above, according to the present invention, it is possible to suppress sputtered particles on the substrate from oblique directions, to improve uniformity, adhesion, film quality and distribution change due to change in erosion depth. A good film quality can be obtained over a long period of time with good adhesion due to thickness distribution.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part around a target according to a first embodiment of the present invention.

FIG. 2 is a schematic plan view of the shielding plate according to the first embodiment of the present invention as viewed from a substrate and a tray.

FIG. 3 is a characteristic diagram showing a distribution of sheet resistance in a direction perpendicular to the movement of the substrate and the tray according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a distribution of moving directions of a substrate and a tray according to the first embodiment of the present invention.

FIG. 5 is a schematic sectional view of a support rod according to a second embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a main part around a target according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Target 2 Substrate and tray 3 Shield plate 4 Support bar 5 Shield plate 6 Sputtered particle 7 Shield plate opening 8 Target erosion outer periphery 9a Width at center of opening 7 9b Width at both ends of opening 10 Target erosion center 11 Protective cover from the shield plate side 12 Protective cover from the shield plate and the housing side 13 Eaves inclined by making the outer peripheral portion of the shield plate closer to the target from the periphery of the opening 14 Sputtered particles oblique to the substrate

Claims (8)

[Claims] 1. A sputtering apparatus in which a shielding plate having a desired opening facing a target is provided between the target and a substrate on which a film is to be deposited. 2. The method according to claim 1, wherein the size of the opening of the shielding plate is different depending on the direction in which the substrate and the tray move and the direction perpendicular to the direction.
2. The sputtering apparatus according to claim 1, wherein the width of the central portion is substantially equal to the width of the target, and the width of both ends is larger than the width of the central portion. 3. The sputtering apparatus according to claim 1, wherein the size of the opening of the shielding plate in a direction perpendicular to the direction in which the substrate and the tray move is smaller than the center of the target erosion. 4. The sputtering apparatus according to claim 1, wherein the shielding plate has a ground potential. 5. The sputtering apparatus according to claim 1, wherein a voltage is applied between the shielding plate and the target. 6. The sputtering apparatus according to claim 1, wherein an outer peripheral portion of the shielding plate is closer to the target than around the opening. 7. A sputtering apparatus according to claim 1, wherein the substrate on which the film is to be deposited is moved past a target. 8. The sputtering apparatus according to claim 1, wherein at least the sputtering surface of the substrate is an insulator, and the adherend is a semiconductor or a conductor.