JPH09143706A - Sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain sputtered films having decreased defects by constituting the sputtering region of a target of a thin film forming material and the non-sputtering region of an insulating material and forming the butt surfaces of both as slopes. SOLUTION: The sputtering region 2 of the target 1 is formed of the thin film forming material and the non-sputtering region 2 is constituted of a block- shaped member consisting of the insulating material. The butt surfaces of the end face of the target material and the block-shaped member are formed as slops so that these surfaces are butted against each other in the state of maintaining snug contact with each other in order to improve the adhesibeness at the end faces of both. The angle θ of inclination when the sectional shape of the thin film forming material of the sputtering region 2 is formed to a trapezoidal shape of which the bottom side is the mounting surface to a backing plate 4 is usually set at <=70 deg., more preferably 20 to 60 deg. and further preferably within a range of 30 to 50 deg..

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a target for DC magnetron type reactive sputtering. More specifically, the present invention relates to a sputtering target that prevents abnormal discharge and enables DC magnetron type reactive sputtering with excellent discharge stability.

[0002]

2. Description of the Related Art Conventionally, as a method for forming a thin film of a metal oxide or nitride on a substrate by sputtering, a target substance and a sputtering gas component (referred to as a reactive gas) are chemically reacted with each other during sputtering film formation. Reactive sputtering for forming these compound thin films is widely used. In the present invention, a method of performing the above reactive sputtering using a DC magnetron sputtering apparatus will be referred to as DC
It is called magnetron type reactive sputtering.

When a thin film of a metal compound is formed on a substrate by DC magnetron type reactive sputtering, the region where the sputtering is predominant depends on the sputtering rate of the metallic compound on the target and the forming rate of the metallic compound on the target. A (sputtering region) and a region (non-sputtering region) where the formation rate of the metal compound is dominant occur on the target.
In the non-sputtering area, an insulative thin film of a metal compound is gradually deposited on the target, and if sputtering is continuously performed, the thin fragile part of the film will cause dielectric breakdown, sparking, and discharging. Becomes unstable. Further, when the deposited film causes a dielectric breakdown, an overcurrent may flow in the destroyed portion, and a lump of molten material may scatter and adhere to the film forming portion on the substrate side to cause a defect.

Therefore, it is necessary to periodically remove the insulating thin film deposited on the non-sputtering area of the target. For that purpose, the sputtering must be interrupted to release the reduced pressure, which is extremely inefficient. is there. Particularly in an in-line type sputtering apparatus, this is a great cause of a decrease in productivity. As a method for solving these problems, the present applicant has previously proposed a target (material for thin film formation).
Method of previously covering the non-sputtering area of the device with an insulating material (Japanese Patent Laid-Open No. 3-100173 and Japanese Patent Laid-Open No. 3-75367).
No.) or a method in which the non-sputtering region of the target is replaced with a block-shaped member made of an electrically insulating material (Japanese Patent Laid-Open No. 3-75366), and the like, it has been proposed that abnormal discharge can be prevented.

However, although the generation of abnormal discharge was greatly reduced by the above-mentioned method, the generation of abnormal discharge was recognized in a slight gap region between the target (material for forming a thin film) and the electric insulating substance. . In this abnormal discharge, an insulating thin film begins to be deposited on both sides of the slight gap between the electrical insulating material and the thin film forming material (actual target portion), and fine dust-like matter is generated in the gap. However, it is considered that abnormal discharge is generated using this dust as a medium.

[0006]

In view of the above problems, the present invention eliminates abnormal discharge of a target and stably forms a sputtered film when forming a metal compound film by DC magnetron type reactive sputtering. However, the purpose is to improve production efficiency.

[0007]

As a result of intensive studies to solve the above-mentioned problems, the present inventor has determined that the target has a specific structure to prevent abnormal discharge and to prevent sputtered films with extremely few defects. The inventors have found that the following can be obtained and completed the present invention. The gist of the present invention is a target used for DC magnetron type reactive sputtering, in which the sputtering region of the target is made of a thin film forming material and the non-sputtering region of the target is made of an electrically insulating material. The sputtering target is characterized in that the abutting surface of the thin film forming material and the electrically insulating material is a surface inclined with respect to the backing plate surface.

An example of the target of the present invention will be described in more detail below with reference to the drawings. 1 is a vertical sectional view showing an example of the target of the present invention, FIG. 2 is a plan view of the target of the present invention, FIG. 3 is a side view of the target of the present invention, and FIG. 4 is a vertical section of another example of the target of the present invention. It is a side view. 1 is a target, 2 is a sputter region, 3 is a non-sputter region,
4 is a backing plate, 5 is a bolt, 6 is a mounting hole, 7
Is an electric insulating tape, 8 is a mating portion, 9 and 9'are divided side blocks, and 10 is a divided central block.

As the target 1 to which the present invention is applied,
If it can be sputtered by DC magnetron type sputtering
Anything, such as Al, Ti, V, Cr, Mn, F
e, Co, Ni, Cu, Zn, Ge, Zr, Nb, M
o, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,
Metals such as Os, Ir, Pt, Au and Th, C, Si,
Non-metals such as Se, Te, Ge, and their compounds
No. In addition, as the reactive gas, the target
Any gas that reacts with wood to form a compound,
For example H_Two, N_Two, O_Two, F, Cl_Two, CH_Four, C_TwoH
_Four, CF_Four, C_TwoF _FourAnd the like.

When a compound is formed by DC magnetron type reactive sputtering using the target 1 and the reactive gas, generally, a portion where the vertical component of the magnetic field of the magnet is large is not sputtered or is hard to be sputtered (non-sputtering). Area 3). A compound of the target 1 and the reactive gas is deposited on these portions, which deteriorates the conductivity and causes the dielectric breakdown as described above.

In the target 1 of the present invention, the non-sputtering region 3 where the compound of the above-mentioned thin film forming material (target material) and the reactive gas is deposited is made of an electrically insulating substance in advance. Typical examples of the electrically insulating substance used include glass, porcelain plate, and ceramic plate, but any substance can be used as long as it is made of an electrically insulating substance.

As shown in the figure, the block-shaped member made of an insulating material is preferably flush with the sputter surface,
Desirably, the thickness is approximately the same as the target material (material for forming a thin film) in the sputtering region, and it is provided around and around the target material (sputtering region 2). Needless to say, the shape of the block-shaped member made of an electrically insulating material varies depending on the shape of the target, the shape of the electrode, and the like. Since the block-shaped member made of an electrically insulating material may have a thickness that does not cause dielectric breakdown, for example, the surface only has an electrically insulating substance having a thickness of about 50 μm or more, preferably 150 μm or more, more preferably 300 μm or more. Although a member covered with a may be used, a member having a thickness similar to that of the target is preferably used from the viewpoint of handling.

In the present invention, the sputter region 2 of the target is formed by the above-mentioned thin film forming material, and the non-sputter region 3 is formed by a block-shaped member made of an insulating material. In order to improve the adhesion at the end faces of both of them, the end face of the target material and the abutting face of the block-shaped member are inclined faces, and both are abutted in a state of being in close contact with each other. When the cross-sectional shape of the thin film forming material in the sputter region is trapezoidal with the attachment surface to the backing plate as the lower side, the inclination angle (θ in FIG. 1) formed by the backing plate surface and the inclined surface is usually 70 ° or less, preferably It is preferably within the range of 20 to 60 °, and more preferably 30 to 50 °. If the inclination angle θ is too large, the adhesion at the end face is reduced and the effect of preventing abnormal discharge is reduced.

The cross-sectional shape of the thin film forming material may be inverted trapezoidal, but in this case, the inclination angle (θ in FIG. 4) is preferably in the range of 120 to 160 °. This inverted trapezoidal cross section is preferable in that the amount of thin film forming material used can be reduced, but since the acute angle portion is located away from the backing plate, the corner portion is apt to be chipped, so handle with care. Requires.

The block-shaped member has the above-mentioned predetermined shape, and is usually attached to the backing plate with a screw such as an adhesive or a screw. In this case, as the adhesive and the screw, an insulating substance, for example, an adhesive made of alumina paste or a screw made of ceramic is preferably used. As shown in FIG. 1, the block-shaped member located in the non-sputtering region 3 is attached with a bolt 5 or the like. At this time, the mounting hole 6 provided in the block-shaped member has a larger diameter than the shaft portion of the bolt 5. As a result, by allowing fine adjustment of the fixed position, the inclined surface of the target material and the inclined surface of the block-shaped member can be brought into close contact with each other. If the upper portion of the bolt 5 is covered with an electrically insulating tape or the like, the bolt 5 made of a conductive material can be used.

As shown in FIGS. 2 and 3, the block-shaped member provided so as to surround the outer periphery of the target material is
If it is divided into a plurality of parts as shown in the figure, it is easy to bring the inclined surfaces into close contact with each other. However, although a gap is formed in the mating portion 8 of the block-shaped members, it is not a big problem because it is a minute gap. Since it is not preferable that the surface of the backing plate 4 is exposed through the gap between the block-shaped members,
The mating portion 8 preferably has a superposed structure as shown in FIG.

Further, when the target material of the sputter region 2 as shown in FIG. 4 is formed into an inverted trapezoidal shape, the block-shaped member forming the central non-sputter region cannot be inserted in the subsequent process, As shown in FIG. 4, it is also possible to divide into side blocks 9 and 9'and a central block 10 and insert them in order. As described above, the target of the present invention does not cause dielectric breakdown because the deposit that causes dielectric breakdown during sputtering is deposited on the block-shaped member made of an insulating material. In addition, since the adhesion between the target end surface and the end surface of the block-shaped member 5 is good, it is possible to prevent abnormal discharge from occurring at the contact portion between the two.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 A Si target was set in an N ₂ / Ar atmosphere at 5 × 10 ⁻³ Torr.
Sputtering was performed at ² W / cm ² . As shown in FIG. 1, a non-sputtered region was formed by using a block-shaped member made of a quartz ring of an insulating material (the inclination angle θ of the end face of the target was 50 °) as the target, and the obtained SiN film was Bite error rate (BER) is 1 × 10 ^-5
Which is 1/7 that of the conventional one.

[0019]

According to the DC magnetron type reactive sputtering target of the present invention, it is possible to stably obtain a sputtered film with extremely few defects, which is very effective in improving the production efficiency.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an example of a target of the present invention.

FIG. 2 is a plan view of a target of the present invention.

FIG. 3 is a side view of the target of the present invention.

FIG. 4 is a vertical sectional view of another example of the target of the present invention.

[Explanation of symbols]

 1 Target 2 Sputter area 3 Non-spatter area 4 Backing plate 5 Bolt 6 Mounting hole

Claims (4)

[Claims] 1. A target used for DC magnetron type reactive sputtering, wherein a sputtering region of the target is made of a thin film forming material and a non-sputtering region of the target is made of an electrically insulating material, and both of them are backing plates. The sputtering target, wherein the butting surface of the thin film forming material and the electrically insulating material is a surface inclined with respect to the backing plate surface. 2. The angle formed by the backing plate surface and the inclined surface when the cross-sectional shape of the thin film forming material in the sputter region is trapezoidal with the attachment surface to the backing plate as the lower side is 70 ° or less. The sputtering target according to claim 1. 3. The angle formed by the backing plate surface and the inclined surface is 20 to 60 °.
The sputtering target according to 1. 4. The angle formed by the backing plate surface and the inclined surface when the cross-sectional shape of the thin film forming material in the sputtering region is an inverted trapezoid with the mounting surface to the backing plate as the lower side is 120 to 160 °. The sputtering target according to claim 1, which is characterized in that.