WO2001034868A1

WO2001034868A1 - Correction method and device for sputtering target/packing plate assembly

Info

Publication number: WO2001034868A1
Application number: PCT/JP2000/004827
Authority: WO
Inventors: Koichi Nakashima; Takakazu Seki; Keiichi Isizuka
Original assignee: Nikko Materials Company, Limited
Priority date: 1999-11-09
Filing date: 2000-07-19
Publication date: 2001-05-17
Also published as: JP2001131738A; JP3568845B2; KR20010093247A; KR100429667B1; TW546397B

Abstract

A correction method for a sputtering target/packing plate assembly, which corrects by vacuum-suction an assembly formed by joining a sputtering target and a packing plate together. When a strain such as a warp and deformation occurred in a sputtering target-packing plate joining process is to be corrected during a target, especially, a ceramics target production process, a strain such as a warp of the target is effectively corrected by a means for uniforming a pressure applied to the sputtering target without cracking to thereby obtain a correction method for a sputtering target/packing plate assembly, and a correction device therefor.

Description

Description Sputtering target Straightening method of Z backing plate assembly and straightening equipment

Technical field

The present invention relates to a method and apparatus for correcting a sputtering target / backing plate assembly that can effectively correct the warpage of a target caused by bonding of a target to a backing plate without causing cracks. Background art

In recent years, sputtering has been used to form thin films for semiconductor devices and various electronic devices. Sputtering has been performed at higher speeds to improve productivity.

As is well known, the above-described sputtering method involves irradiating charged particles toward a target, hitting the particles from the target by the particle impact force, and forming the target material on a substrate such as a wafer facing the target, for example, a wafer. This is a film forming method for forming a thin film mainly composed of a substance.

Since the target is subjected to a large amount of impact of charged particles during sputtering, the temperature of the target gradually increases. Therefore, it is necessary to cool the target, and in many cases, a material with good thermal conductivity (backing plate) such as pure copper or copper alloy is brazed to the back of the target, diffusion bonding, crimping, bonding using the anchor effect, etc. The backing plate is cooled by external cooling means to absorb the heat of the sputtering target. As described above, in order to join the sputtering target to the backing plate, it is necessary to heat to the appropriateness in various joining methods, and after joining, it is cooled. The problem of warpage and deformation caused by the difference in the thermal expansion coefficient between the target and the backing plate due to the thermal effect of the force during the bonding [I].

Once warpage or deformation occurs, it is difficult to correctly set it in the sputtering equipment unless it is corrected, and cooling is biased during the sputtering operation and uniform cooling is not performed. Problems arise.

For this reason, it is necessary to repair the warped target. However, the larger the target, the greater the degree of deformation, and there was a problem that the target cracked during the warp repair work.

In addition, if repair such as warpage is not performed properly, caloric heat is generated during sputtering as described above, and the thermal stress and the inherent strain are combined, so that a crack is generated in the sputtering target. May occur.

In such a case, a large amount of particles are generated at the moment when the sputtering target is broken, resulting in a defective film or a missing sputtering target, making it impossible to continue the sputtering. This can be a major problem, as it can cause significant damage to the equipment.

From the viewpoint of the types of sputtering target materials, ceramic targets are brittle and have a small coefficient of thermal expansion, and the difference in coefficient of thermal expansion from backing plate materials such as pure copper alloys is large. Warpage or cracking is more likely to occur than the target.

In an attempt to solve such a problem, it has been proposed to use a low-melting-point solder for bonding so that heat is not applied to the target and the backing plate at a high temperature. However, in this case, the bonding strength is weak, and when the target is heated to a high temperature by performing sputtering, there is a problem that the solder for bonding melts out, and this has not been solved. In addition, in order to reduce the thermal expansion between the sputtering target and the backing plate, it has been proposed to form a plurality of bonding layers having different thermal expansions in stages (Japanese Patent Application Laid-Open No. Sho 61-250016). 7). However, such means is not practical because the operation steps become complicated and the manufacturing cost increases.

Furthermore, in the joining process between the target and the backing plate, a method of mechanically applying a force in the opposite direction to the warped target to correct it, or taking into account the amount of warpage before joining, A proposal has been made (Japanese Patent Application Laid-Open No. 1-126209) to join a target after giving it a reverse warp.

In the case of brittle materials such as ceramics, in particular, mechanical stresses higher than the material strength are applied in the process of applying the conventional correction and deformation by mechanical pressing, so that the material is cracked by force. ^^, which was not a valid solution. Disclosure of the invention

The inventors of the present invention equalize the pressing force applied to the sputtering target when correcting distortion such as warpage or deformation generated in the joining process between the sputtering target and the backing plate in the process of manufacturing the target, particularly the ceramic target. Means for obtaining a method and a device for correcting a sputtering target Z backing plate assembly, which effectively corrects distortion such as warpage of a target without generating cracks, by means.

According to the present invention, it has been found that uneven pressing force at the time of straightening of a sputtering target rather induces cracks. A method and apparatus for correcting a sputtering target / backing plate assembly which effectively corrects the distortion of the sputtering target. 1. A method for correcting a sputtering target Z backing plate assembly, wherein the assembly in which the sputtering target and the backing plate are joined is evacuated and corrected.

2. The straightening of the sputtering target Z backing plate assembly as described in 1 above, wherein the sputtering target no-packing plate assembly is placed on a surface plate having a vacuum suction hole, and is corrected by vacuum suction from the vacuum suction hole. Method

3. The method for correcting a sputtering target / backing plate assembly according to 1 or 2 above, wherein the flexible sheet is covered on the sputtering target Z backing plate assembly and vacuum suction is performed.

4. A straightening device for a sputtering target Z backing plate assembly including a surface plate having a vacuum suction hole, a vacuum exhaust device, and a flexible sheet covering the sputtering target Z backing plate assembly.

5. The straightening device for a sputtering target Z backing plate assembly as described in 4 above, wherein the sputtering target is a ceramic target.

6. The straightening device for a sputtering target / backing plate assembly according to the above item 4 or 5, wherein the backing plate is a metal having good thermal conductivity.

FIG. 1 is a conceptual diagram of a device for correcting a sputtering target backing plate assembly according to the present invention. Embodiment of the Invention

In general, the ceramic target has a small coefficient of thermal expansion, and the difference between the coefficient of thermal expansion and the backing plate made of copper or the like is large. For this reason, warping and cracking occur more frequently than a metal-based target, and naturally, the amount of strain increases as the sputtering target becomes larger. In a straightening method that presses a warped target with a pressing jig, we examined the phenomenon of cracking of the sputtering target.As a result, a force [1 pressure was locally applied to the target, which caused cracking. I found out.

Therefore, we considered making the pressure applied to the target evenly applied to the entire surface of the target.

According to the present invention, this can be achieved by performing vacuum suction and correcting a solid body in which a sputtering target and a backing plate are joined.

Specifically, as shown in FIG. 1, an assembly 5 in which a sputtering target 3 and a backing plate 4 are joined to a flat surface plate 2 having vacuum suction holes 1, that is, a sputtering target / backing plate assembly 5 is provided. It is intended to correct by vacuum suction through the vacuum suction hole 1.

As shown in FIG. 1, the sputtering target backing plate assembly is warped. The amount of warpage adjustment is adjusted by adjusting the height of the spacer 8 placed between the outer circumference of the surface plate 2 and the backing plate 4.

In order to effectively correct the sputtering target backing plate assembly 5 by vacuum suction, it is necessary to cover the flexible sheet 6 on the sputtering target / backing plate assembly 3D and vacuum suction. preferable.

As a material of the flexible sheet 6, a sheet made of a highly ductile material such as silicone rubber, natural rubber, isoprene rubber, nitrile rubber, and fluoro rubber can be used. In particular, silicone rubber is preferred, but materials other than the above may be used. In addition, in order to perform the correction effectively, the sputtering target Z backing plate assembly 5 can be heated with a force of tl, that is, the correction can be performed during the maturity.

For example, in the case of a sputtering target Z backing plate assembly bonded using indium brazing, straightening can be performed by heating to a melting point of indium brazing up to 156 ° C. In the case of heating more than that, it can be corrected by using a high melting point brazing, for example, using heat resistant silicone rubber (having heat resistance up to 280 C). In this manner, the soldering material for bonding and the flexible sheet are appropriately selected according to the heating temperature of the sputtering target Z backing plate assembly which is the object to be heated. Of course, if the correction is made by this method, it is necessary to cool to room temperature while performing the correction.

The only equipment required in the apparatus of the present invention is a flat platen 2 having a vacuum suction hole 1, a vacuum exhaust device 7, and a sputtering target backing plate assembly. Thus, the sputtering target / backing plate assembly can be sufficiently corrected.

Since the ceramic target is a brittle material having a small coefficient of thermal expansion and a material having a large difference in coefficient of thermal expansion from a packing plate material such as an alloy, the tendency of such warping or cracking is strong. It is extremely effective to prevent the occurrence of cracks in such a ceramic target.

Hereinafter, description will be made based on examples and comparative examples. This embodiment is merely an example, and the present invention is not limited to this example. That is, the present invention includes other aspects or modifications included in the technical concept of the present invention.

(Example)

30 pieces of backing plate made of oxygen-free copper with dimensions 860 x 970 x 11 '(mm) and indium-tin-tin composite oxide (ITO) with dimensions 810 x 910 x 6 [(mm)] Combination of 30 pieces, oxygen-free copper backing plate with dimensions 910 x 1010 x 11 t (mm) 30 pieces and 860 x 950 x 6 '(mm) dimension tin oxide (ITO) 6 Combination of 30 split targets, And 40 oxygen-free copper 980 x 1 140 x 11 '(mm) backing plates and 930 x 1080 x 6 ^C (mm) indium-tin-tin composite oxide (ITO) 8 split targets 40 100 pairs of indium-tin-tin composite oxide (ITO) targets Z backing plates, each consisting of a combination of the above, are bonded together using an adhesive (melting point: 156 ° C) to produce 100 sets of sputtering target / backing plate assemblies did.

As shown in FIG. 1, this sputtering target Z backing plate assembly was warped by 3.5 to 5.5 mm after bonding. In FIG. 1, the amount of warpage is exaggerated for easy understanding.

Next, in order to correct the warpage, the sputtering target Z backing plate assembly 5 was placed on a flat surface plate 2 having vacuum suction holes 1. The warpage was adjusted by adjusting the height of the spacer 8.

After covering the whole of the sputtering target backing plate assembly 5 with a silicon rubber sheet 6, vacuum suction was performed through a vacuum suction hole 1 using a vacuum exhaust device.

As a result, the warping of the above-mentioned 100 sets of sputtering target / packing plate assemblies was corrected and flattened from 0 mm to 1.5 mm, and none of the sets produced cracks due to this correction.

That is, as shown in this embodiment, the correction by vacuum suction can correct the target without cracking.

(Comparative example)

As in Example 1, 30 backing plates made of oxygen-free copper and having a size of 860 x 970 x 11 '(mm) and an indium-tin-tin composite oxide (I) having a size of 810 x 910 x 6' (mm) were used. TO) Combination of 30 6-split targets, oxygen-free copper backing plate with dimensions 910 x 1100 x 1 ¹ (mm) and indium-tin composite with dimensions 860 x 950 x 6 '(mm) Combination of 30 sheets of acid-rich (ITO) 6-split target And oxygen-free copper dimensions 980 X ¹ 140 X 1 1 1 indium tin composite Sani匕物backing plates 40 sheets (mm) and dimensions ^{930 X 1080 X 6 1 (mm} ) (I TO) 8 divided Target 100 sets of indium-tin-tin composite oxide (ITO) target Z backing plates consisting of 40 combinations are joined together using an adhesive (melting point: 156 ° C), and 100 sets of sputtering target / backing plate assemblies Who did

This sputtering target Z backing plate assembly was warped by 3.5 to 5.5 mm after bonding, as in the example.

Next, to correct this warpage, the sputtering target / backing plate assembly was placed on the platen 2 of the press, and the sputtering target Z backing plate assembly was covered using a silicon rubber sheet as a cushioning material. Thereafter, a load of 500 kg was applied to correct the target.

As a result, the warping of the above-mentioned 100 sets of sputtering target Z backing plate assemblies was corrected and flattened to 0.5 to 2.5 mm, but cracks occurred in 3 sets by this correction. The crack occurrence rate was 3%, and those with cracks were sent to the material recycling process as defective products. Further, the flatness was insufficient as compared with the present invention.

As described above, it can be seen that even if the correction by the conventional mechanical pressing can correct the warp, the flatness is poor, and the pressing force locally varies, and the occurrence of cracks increases. The invention's effect

In the manufacturing process of a sputtering target, especially a ceramic star target, when correcting distortion such as warpage or deformation generated in a joining process between a sputtering target and a backing plate, a vacuum suction means for equalizing a pressing force applied to the sputtering target is used. An excellent effect is obtained if distortion such as warpage of the target can be effectively corrected without generating cracks.

Claims

The scope of the claims

1. A method for correcting a sputtering target / backing plate assembly, which comprises vacuum-correcting a thread and a solid body in which a sputtering target and a backing plate are joined together.

2. The sputtering target backing plate according to claim 1, wherein the sputtering target Z backing plate assembly is placed on a surface plate having a vacuum suction hole, and is corrected by vacuum suction from the vacuum suction hole. How to straighten the assembly.

3. The method for correcting a sputtering target Z-backing plate assembly according to claim 1, wherein a flexible sheet is put on the sputtering target Z-backing plate assembly and vacuum suction is performed.

4. Sputtering target equipped with a platen with vacuum suction holes, a vacuum exhaust device, and a flexible sheet covering the sputtering target / packing plate assembly.

5. The straightening device for a sputtering target Z backing plate assembly according to claim 4, wherein the sputtering target is a ceramic target.

6. The straightening device for a sputtering target / backing plate assembly according to claim 4, wherein the backing plate is a metal having good thermal conductivity.

Claims of amendment

[January 19, 2000 (19.1.00) Accepted by the International Bureau: Claim 1 at the time of filing was withdrawn; other claims remain unchanged. (1 page)]

1. (Delete)

2. Place a sputtering target Z backing plate and solid on a surface plate with vacuum suction holes, apply vacuum suction from the vacuum suction holes, and vacuum suction the assembly that joins the sputtering target and the backing plate. A method of straightening a sputtering target backing plate assembly, comprising straightening.

3. The method for correcting a sputtering target Z backing plate assembly according to claim 2, wherein a flexible 14 sheet is placed on the sputtering target / backing plate assembly and vacuum suction is performed.

4. Sputtering target equipped with a surface plate with vacuum suction holes, a vacuum exhaust device, and a flexible sheet covering the sputtering target backing plate assembly Z Straightening device for backing plate assembly So

5. The straightening device for a Z backing plate assembly according to claim 4, wherein the sputtering target is a ceramic target.

6. The straightening device for a sputtering target / backing plate assembly according to claim 4 or 5, wherein the backing plate is a metal having good heat conductivity.

Amended paper (Article 19 of the Convention)