KR20020022502A - Large area magnetron source and back plate - Google Patents

Abstract

PURPOSE: A large area magnetron source and a back plate are provided to uniformly distribute magnitude of magnetic field in front of the magnet by improving the structure of a magnet, thereby preventing distortion of plasma caused by imbalance of magnetic field of the central part and the edge of the magnet. CONSTITUTION: In a magnetron sputter for forming a thin film on a substrate, the large area magnetron source comprises a first permanent magnet(4b) which is magnetized by a first polarity, and widths of the central part and the edge of which are different from each other; and a second permanent magnet(4a) which is magnetized by a second polarity, both edges(8a,8b) of which are formed in a semicircle shape, and which envelopes the first permanent magnet(4b) with spaced apart from each other in a certain gap(7), wherein the large area magnetron source further comprises a target containing a material to be deposited on the substrate; and a back plate to the front of which the target is adhered, and the backside of which is faced with the first and second permanent magnets each other. The back plate comprises a target containing a material to be deposited on the substrate; a first back plate which is selected from metals having a high thermal conductivity, and supports the target; a second back plate which is selected from metals having a high mechanical strength, and coupled to the first back plate; and a vacuum layer which is formed between the first back plate and the second back plate.

Description

Large Area Magnetron Source and Back Plate

The present invention relates to a magnetron sputtering apparatus for forming a thin film on a large-area substrate, and more particularly, to a large-area magnetron source and a back plate for uniformizing the strength of a magnetic field.

Recently, development of flat panel displays (FPDs), such as liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), It's accelerating. In addition, the memory field has continued to develop ultra-fine and large-capacity due to the development of semiconductor processes.

BACKGROUND OF THE INVENTION A manufacturing process of a flat panel display or a memory involves a metal wiring or an electrode deposition process. For example, a transparent conductive electrode material such as indium tin oxide (ITO) is deposited on a substrate using a magnetron sputtering device.

The magnetron sputtering device exhausts the vacuum chamber on which the substrate is mounted to the lowest achieved vacuum degree (<10 ^-7 Torr) using an exhaust device, and then introduces an inert gas such as argon (Ar), which is used as a sputtering gas, into the vacuum chamber. . The argon gas is ionized by applying a voltage to the magnetron source to cause a plasma discharge, and is accelerated toward the target of the material to be deposited. The ionized argon ions then collide with the negatively applied target, thereby releasing target atoms. The released atoms diffuse toward the substrate and are deposited on the substrate.

In the magnetron sputtering apparatus, as shown in FIG. 1, the magnetron source includes a target 21 of a material to be deposited, a back plate 22 to which the target 21 is bonded, and a back plate 22. Cooling line (23) installed in the inside, and the magnet (Magnet) 24 provided on the back plate 22 is provided. The substrate 26 is provided below the target 21. The back plate 22 requires high heat transfer, high electrical conductivity, nonmagnetic, high mechanical strength, and the like. To this end, the back plate 22 is usually made of metal such as aluminum, copper, copper / stainless steel, aluminum / stainless steel, or the like. The cooling line 23 serves to cool high heat generated during target sputtering. The magnet 24 generates a magnetic field. On the back of the magnet 24, a pole piece 25 is fastened so that the magnetic field is strongly concentrated toward the front side. The pole piece 25 is mainly made of pure iron.

As shown in FIG. 2, the magnet 24 is a bar magnet 24a magnetized by the N pole, and a bar magnetized by the pole S, surrounded by the square band magnet 24a with a predetermined gap 27 therebetween. Magnet 24b. The magnetization arrangement of the magnet 24 causes the electrons to move toward the target 21 in the closed path since the motion of the electrons used for ionization moves counterclockwise according to Fleming's left hand law.

In the magnetization arrangement of the magnets 24, the strength of the magnetic field is greatest at the gap 27 between the N pole and the S pole. For this reason, target sputtering occurs in the gap 27 intensively. In particular, since there exists a right-angled part of the square strip 24a in which both edges of the magnet 24 are magnetized to the N pole, the intensity of the magnetic field is concentrated in these parts 28a and 28b. As a result, in the conventional magnetron sputtering apparatus, since the plasma is distorted at both edges 28a and 28b of the magnet source, there is a problem that the uniformity of the thin film deposited on the substrate 26 is inferior.

In addition, the conventional magnetron sputtering device has a problem that it is difficult to manage the mechanical strength as the substrate 26 becomes large, and it is difficult to manage the strength of the magnetic field to a stable level. In detail, since the size of the vacuum chamber increases as the substrate becomes larger, a force generated by a pressure difference of 1 atm is applied to the back plate 22 existing at a position where vacuum and atmospheric pressure contact each other inside and outside the vacuum chamber. At this time, since the force is proportional to the cross-sectional area to which the pressure is applied, the force applied to the back plate 22 increases when the vacuum chamber becomes large, and thus the mechanical strength of the back plate 22 must increase in proportion to the size of the vacuum chamber. However, in order to increase the mechanical strength of the back plate 22, increasing the thickness of the back plate metal increases the strength of the magnetic field since the strength of the magnetic field is inversely proportional to the cube of the thickness of the back plate. On the other hand, in order for the magnetron sputtering to occur stably, the surface magnetic field strength of the target 21 should be about 200 to 500G.

In addition to these problems, in the conventional magnetron sputtering apparatus, since the temperature of the target 21 rises to a high temperature by sputtering, not only the cooling line 23 is required to cool this high temperature but also the cooling line 23 is a back plate. Since it is installed in the (22), there is a disadvantage that the mechanical strength of the back plate 22 is weakened.

Accordingly, it is an object of the present invention to provide a large area magnetron source and a back plate to equalize the strength of the magnetic field.

1 is a cross-sectional view showing a magnetron source in a conventional magnetron sputtering apparatus.

FIG. 2 is a plan view illustrating a magnetization arrangement of the magnet illustrated in FIG. 1. FIG.

3 is a cross-sectional view showing a magnetron source in the magnetron sputtering apparatus according to an embodiment of the present invention.

4 is a plan view showing a magnetization arrangement of the magnet shown in FIG.

<Description of Symbols for Main Parts of Drawings>

1,21: target 2,9,22; Back plate

3,23 Cooling line 4,24 Magnet

5,25 pole piece 6,26 substrate

7, 27: gap 10: vacuum layer

11: screw

In order to achieve the above object, the magnetron source of the large-area magnetron sputtering apparatus according to the present invention is a large-area magnetron source to equalize the strength of the magnetic field in the longitudinal direction is magnetized to the first polarity and the first and the width of the center and the edge is different And a second permanent magnet magnetized with a second polarity, the second permanent magnet having both edges as semicircles and surrounding the first permanent magnet with a predetermined gap therebetween.

The back plate for the magnetron sputtering apparatus according to the present invention is selected from a target containing a material to be deposited on a substrate, a metal having a high thermal conductivity to support the target, and a first back plate and a metal having a high mechanical strength. And a second back plate engaged with the first back plate, and a vacuum layer formed between the first back plate and the second back plate.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 and 4.

3 and 4, the magnetron source of the magnetron sputtering apparatus according to the present invention includes a target 1, a first back plate 9 to which the target 1 is bonded, and a first back plate 9. The second back plate 2 to be fixed and the magnet 4 provided above the second back plate 2 are provided. The substrate 6 is installed in the vacuum chamber to face the target 1. The first back plate 9 serves to support heat dissipation and cooling of the heat of the target 1 heated by sputtering. To this end, the first back plate 9 is made of a metal having high thermal conductivity, for example, aluminum (Al), and cooling lines 3 to which cooling water is supplied are installed at predetermined intervals. Here, the pressure of the cooling water is controlled to be equal to or less than a predetermined atmospheric pressure (about 1.5 atm) to prevent deformation due to the pressure difference between the hydraulic pressure of the cooling water line and the external vacuum. Since the cooling line 9 having a relatively sufficient size can be installed in the first back plate 9, the cooling efficiency can be increased by that much. The second back plate 2 fixes the first back plate 9 by a screw 11 to support the first back plate 9. The second back plate 2 is made of a metal having a high mechanical strength, for example, stainless steel (SUS), to sufficiently withstand the force exerted on itself by the pressure difference between the inside and the outside of the vacuum chamber. In addition, a groove 2a is formed in the bottom of the second back plate 2 such that deformation of the second back plate 2 is not transmitted to the first back plate 1. The grooves 2a form a vacuum layer 10 having a predetermined thickness (about 5 mm) between the first back plate 9 and the second back plate 2. In order to maintain the degree of vacuum of this vacuum layer 10, the vacuum layer 10 is hermetically maintained by the first back plate 9 exposed in the vacuum chamber and the second back plate 2 fixed to the back thereof, A path through which the air in the vacuum layer 10 can be drawn out is formed between the first back plate 9 or the second back plate 2 or therebetween.

Since the back plate is divided into a first back plate 9 in which the cooling line 3 is installed and a second back plate 2 supporting the back plate, the target plate 1 and the first back plate 9 are supported and vacuumed. The mechanical strength of the second back plate 2, which is forced by the pressure difference in and out of the chamber, becomes large. In addition, in consideration of the deformation or warpage of the second back plate 2 due to the force applied to the second back plate 2, the vacuum layer 10 between the first back plate 9 and the second back plate 2. Since it is formed, deformation of the first back plate 9 is not transmitted to the first back plate 9 and the target 1.

The magnet 4 generates a magnetic field, and a pole piece 5 is fastened to the rear thereof so that the magnetic field is strongly concentrated toward the front side. As can be seen in FIG. 4, the magnet 4 is surrounded by an outer ring magnet 4a magnetized by the N pole and the outer ring 4a with a predetermined gap 7 interposed therebetween and magnetized to the S pole. The multi-width bar magnet 4b is included. The width W1 of the central wide portion of the multi-width bar 4b disposed at the center is set to be twice as large as the width W3 of the outer ring 4a. This causes the magnetic field to be uniformly formed in proportion to the straight section of the outer ring magnet 4a disposed on both sides with respect to the multi-width bar 4b. The width W2 of the gap 7 located between the outer ring magnet 4a and the multi-width bar magnet 4b remains the same as the width W1 of the multi-width bar magnet 4b. Both edges 8a and 8b of the magnet 4 have relatively high magnetic field strengths compared to the center portion, so that both edges of the outer ring magnet 4a are relaxed so that the magnetic field is uniformly distributed over the front of the magnet 4. 8a and 8b) are semi-magnet magnets assembled. Further, both ends of the multi-width bar magnet 4b are connected to the wing magnet 4c at a narrow width W4 and a semicircular disk magnet 4d having the same diameter d as the central wide portion.

The size of the magnetron sputtering apparatus must be determined so that the substrate 6 is located in the central wide portion of the multi-width bar magnet 4b.

As described above, the large-area magnetron source and the back plate according to the present invention improve the structure of the magnet 4 to uniformly distribute the intensity of the magnetic field in front of the magnet 4. Therefore, plasma distortion caused by the magnetic field balance of the center and the edge of the magnet 4 can be prevented. In addition, according to the large-area magnetron source and the back plate according to the present invention, the mechanical strength of the back plate is improved even by the pressure difference between the inside and the outside of the vacuum chamber which is increased by the trend of larger size by the large area substrate 6 by improving the structure of the back plate. It can be kept stable as well as preventing deformation of the back plate from being transmitted to the target. In addition, according to the present invention, even if the overall thickness (t_back) of the back plates (2, 9) is maintained at about the same level as before by the back plates (2, 9) separated into two parts, the mechanical strength can be enhanced. Can be. Therefore, it is not necessary to increase the thickness of the back plate, so that the intensity of the magnetic field generated from the magnetron source can be maintained above a certain level. Furthermore, according to the present invention, since the first back plate 9 to which the target is fixed is made of a metal having high thermal conductivity and heat dissipation characteristics and a cooling line is installed therein, cooling efficiency is improved.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (11)

In the magnetron sputtering apparatus for forming a thin film on a substrate, A first permanent magnet magnetized to the first polarity and having a different width at the center and the edge; A large-area magnetron source magnetized to a second polarity and having a second permanent magnet surrounded by the first permanent magnet with a predetermined gap between both edges as semicircles. The method of claim 1, A target including a material to be deposited on the substrate, The large-area magnetron source further comprises a back plate having the target attached to a front surface thereof and a back plate facing the first and second permanent magnets. The method of claim 1, And the second permanent magnet has a uniform width. The method of claim 3, wherein The central magnet located in the central portion of the first permanent magnet has a larger magnetron source, characterized in that having a width larger than the width of the second permanent magnet. The method of claim 4, wherein The center magnet width of the first permanent magnet is set to twice the width of the second permanent magnet, the large area magnetron source. The method of claim 5, At both ends of the central portion of the first permanent magnet and a narrow wing magnet, A large-area magnetron source, characterized in that the semi-circular disk magnet of the same diameter as the center portion is connected in series. In the magnetron sputtering apparatus for forming a thin film on a substrate, A target including a material to be deposited on the substrate; A first back plate selected from a metal having high thermal conductivity to support the target, A second back plate selected from a metal having high mechanical strength and fastened to the first back plate; And a vacuum layer formed between the first back plate and the second back plate. The method of claim 7, wherein The first back plate is a magnetron sputtering device back plate, characterized in that made of aluminum. The method of claim 7, wherein The second back plate is a back plate for a magnetron sputtering device, characterized in that made of stainless. The method of claim 7, wherein The first back plate is a back plate for a magnetron sputtering apparatus, characterized in that the cooling lines supplied with the cooling water is installed therein. The method of claim 7, wherein The bottom surface of the first back plate is a back plate for a magnetron sputtering device, characterized in that the groove is formed to a predetermined depth so that the vacuum layer is provided.