JPH0790576A - Sputtering target - Google Patents

Abstract

PURPOSE:To reduce the particles generated while a film is formed by suppressing the deposition of a sputtered material in a non-erosion region. CONSTITUTION:This sputtering target 1 is used in the sputtering of magnetron type. The surface of the target forming a non-erosion region is formed on a plane 7 lower than the surface 6 of an erosion region. Consequently, the sputtered material is not deposited on the target 1 surface, a film is continuously formed for a long term in the environment where the number of the particles generated is reduced, and defective products, e.g. disconnection in a high-density IC, are decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target used in magnetron sputtering in which a magnetic field is formed on the surface of a target for sputtering.

[0002]

2. Description of the Related Art Conventionally, in magnetron sputtering, a flat plate-shaped sputtering target a as shown in FIG.
Is used. Behind the target a, a magnet b is provided for generating a magnetron discharge, and the magnet b forms a racetrack-shaped magnetic field c orthogonal to the electric field on the target surface. Electrons move in a space surrounded by to create high-density plasma near the surface of the target a for sputtering. Reference numeral d in the figure is a backing plate formed of a water-cooled copper plate, and a target a is attached to the surface thereof by bonding or the like.

[0003]

The surface of the target a to be sputtered is formed to be flat. When sputtering is performed, the surface is not consumed with the erosion region e consumed by the sputtering, as shown in FIG. It is divided into a non-erosion area f. One of the reasons why the ultra-high density IC becomes a defective product is the disconnection of the circuit. When the cause of the disconnection is sought, the spattered material g is deposited in the non-erosion area f, and this deposited material is formed during the film formation. It turned out that the particles are attached to the substrate as particles.

It is an object of the present invention to provide a target capable of suppressing the deposition of sputtered material in the non-erosion region and reducing the particles generated during film formation.

[0005]

According to the present invention, in a sputtering target used for magnetron type sputtering, a surface which is a non-erosion region of the sputtering target is formed to be lower than a surface of the erosion region. Thus, the above-mentioned object is achieved. For the sputtering target, a thick target member and a thin target member are prepared,
A thick target member can be arranged in the erosion region and a thin target member can be arranged in the non-erosion region to form a mosaic structure.

[0006]

When the sputtering target is bonded to a backing plate, a magnet is positioned behind the sputtering target and is provided in a vacuum chamber, and high frequency power is applied to the target from a high frequency power source in the same manner as in normal sputtering, the vicinity of the surface of the target is Magnetron discharge is generated in the region surrounded by the magnetic field, and the target material is sputtered by the ions of the sputtering gas ionized by the discharge, and adheres to the substrate such as a silicon wafer in front of the target in a thin film form. While the surface of the target is flat, sputtered particles fly in a certain direction, but the surface of the target is not uniformly sputtered. The non-erosion area remains as a convex portion, and the particles sputtered on the convex portion hit and deposit on the convex portion, which may peel off during sputtering or cause a partial abnormal discharge. It is not preferable because it causes The portion that becomes the non-erosion region can be determined in advance, and in the present invention, by forming the surface of the non-erosion region lower than the surface of the erosion region in advance, it is possible to prevent sputtered particles from being deposited. No more parts,
Generation of dust can be prevented.

[0007]

Embodiments of the present invention will be described with reference to the drawings.
In FIG. 3, reference numeral 1 denotes a target bonded to a backing plate 2 made of a water-cooled copper plate, and a magnetic field as shown by a dotted line is formed on the surface of the target by a magnet 3 behind it. The target 1 is provided with its surface facing the substrate such as a silicon wafer (not shown) in the vacuum chamber 4. The target 1 is connected to a high frequency power source 5 and discharges with respect to the wall surface of the vacuum chamber or the like at the earth potential. At this time, the electrons in the discharge move by being restrained by the magnetic field, resulting in a so-called magnetron discharge. Ionized ions sputter the surface of the target 1, and the generated particles adhere to the substrate in a thin film form.

If the surface of the target 1 is a uniform flat surface, the disadvantage that particles are deposited in the non-erosion region which is not consumed by the sputtering as described above occurs. However, in the present invention, the non-erosion region is present. The target 1 at a position corresponding to is formed on the surface 7 lower than the surface 6 in the erosion region to solve the inconvenience.

When the magnetic field shape of the target 1 is determined, the erosion region and the non-erosion region are determined.
A low surface 7 is formed by cutting the target in a portion corresponding to the non-erosion region as shown in FIG. 3, or as shown in FIG. 4, a thick target member 1a and a thin target member 1b having several thicknesses are used. It is also possible to combine the above in a mosaic manner to form the thick target member 1a in the erosion region and the thin target member 1b in the non-erosion region.

Explaining the operation in the case shown in FIG. 3, high-frequency power is supplied to the target 1 to generate magnetron discharge spatter, and with this spatter, a dense plasma corresponding to the intermediate portion of the magnetic field with the passage of time. The surface 6 in the portion where the slag is generated becomes an erosion region and is gradually consumed. However, since the non-erosion region is the surface 7 lower than the surface 6, the sputtered particles are discharged to the outside of the target 1 as shown in FIG. It is not scattered and deposited on the surface of the target 1, and it is possible to eliminate the inconvenience of becoming particles during the film formation and adhering to the substrate.

For comparison, when magnetron sputtering was performed using a conventional target having a flat surface, as shown in FIG. 6, the number of processed substrates was 15 as time passed.
The number of generated dusts (particles) exceeded 1500 when the number of sheets reached about 0. However, when the target 1 of the present invention was used, as shown in FIG.
The number of dusts generated was about 500 even in the case of about one sheet, and the film formation process could be performed on a substrate about 5 times as large as that in the conventional case under the condition of less dust generation.

In the embodiment shown in FIG. 3, the target 1
A circular target member having a diameter of 250 mm and a thickness of 8 mm is formed with a hollowed hole having a diameter of 75 mm and a depth of 4 mm in the central part, and a peripheral surface of the hole is cut to a width of 15 mm and a depth of 4 mm to form a lower surface 7. did. Further, in the embodiment of FIG. 4, the thick target member 1a is composed of an annular member having an outer diameter of 220 mm and a through hole having a diameter of 75 mm at its center, and a disk having a diameter of 75 mm and a thickness of 4 mm is attached to the through hole. At the same time, the outer diameter of the annular member is 250 mm and the diameter is 220 mm at the center.
A thin target member was prepared by mounting an annular member having a thickness of 4 mm and a thickness of 4 mm. As with the target of FIG. 3, the target of FIG. 4 produced less dust. Furthermore, when the hollowed hole of the target 1 shown in FIG. 3 was tapered outwardly by 60 ° and a sputtering test was conducted under the same conditions as in FIG. 3, the same effect as in the case of FIG. 3 was obtained.

[0013]

As described above, according to the present invention, the surface of the sputtering target used for magnetron type sputtering, which is the non-erosion region, is formed lower than the surface of the erosion region. It is possible to prevent deposition on the surface of the device, so that film formation can be continued for a long time in an environment in which the number of generated particles is reduced, and it is possible to reduce the defective product occurrence rate such as disconnection of high-density IC. And so on.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a target used in conventional magnetron sputtering.

FIG. 2 is a cross-sectional view of the operating state of the target of FIG.

FIG. 3 is a partially cutaway perspective view of an embodiment of the present invention.

FIG. 4 is a partially cutaway perspective view of another embodiment of the present invention.

FIG. 5 is a sectional view of an operating state of the target of the present invention.

FIG. 6 is a measurement diagram of a dust generation state when a conventional target is used.

FIG. 7 is a measurement diagram of a dust generation state when the target of the present invention is used.

FIG. 8 is a partially cutaway perspective view of the modified example of FIG.

9 is a partially cutaway perspective view of another modified example of FIG.

FIG. 10 is a partially cutaway perspective view of the modified example of FIG.

[Explanation of symbols]

1 Target 1a Thick Target Member 1b Thin Target Member 3 Magnet 6 Erosion Area Surface 7 Low Surface

Claims (2)

[Claims] 1. A sputtering target used for magnetron type sputtering, wherein a surface of the sputtering target which is a non-erosion region is formed lower than a surface of the erosion region. 2. The sputtering target comprises a thick target member and a thin target member,
The sputtering target according to claim 1, wherein a thick target member is arranged in the erosion region and a thin target member is arranged in the non-erosion region to form a mosaic structure.