TWI429777B - Cocrpt-based alloy sputtering targets with cobalt oxide and non-magnetic oxide and manufacturing methods thereof - Google Patents

Description

Cobalt-chromium-platinum-based alloy sputtering target containing cobalt oxide and non-magnetic oxide and manufacturing method thereof

The invention relates to a cobalt chrome-platinum-based alloy sputtering target containing cobalt oxide and non-magnetic oxide, and a manufacturing method thereof, in particular to a cobalt with uniform composition distribution and reducing arc discharge and particle phenomenon generated during sputtering process. A method for producing a chromium-platinum-based alloy sputtering target.

In general, a sputtering target of a CoCrPt-based alloy containing a non-magnetic oxide is used for a recording layer of a perpendicular magnetic recording media. The film of the layer is usually formed by sputtering in the industry; in the process of sputtering such a target, oxygen is required as a reaction gas (ie, reactive sputtering). However, if excessive oxygen is introduced, the highly reactive metal contained in the target easily reacts with oxygen to cause arcing and particles.

In order to solve the above problems, some people try to add cobalt oxide (CoO) to the target. The cobalt oxide will decompose during the sputtering process to form cobalt atoms and highly reactive oxygen radicals, which will react with the reactive The metal reacts and deposits on the surface of the substrate. Oxygen radicals can provide a higher free energy than oxygen molecules, and are more likely to segregate the oxides produced by them into the grain boundary of the metal species (ie, CoCrPt alloy) in the magnetic recording medium. A good barrier to avoid mutual interference between the magnetic recording signals, so that no oxygen is required to be used as the reaction gas. However, it can be seen from the Ellingham diagram and the experimental results that cobalt oxide reacts with the chromium in the target to form a thick strip of chromium oxide (such as chromium oxide (Cr _{2 ).} O ₃ )) agglomerates, which tend to cause uneven distribution of components in the target, and also cause problems such as arc discharge and particle generation during sputtering.

WIPO Patent Publication No. 2007/116834 discloses a method for producing a Co-based sintered alloy sputtering target for forming a magnetic recording film, which is a cobalt containing 50 to 70 at% of chromium metal. The chromium prealloyed powder is mixed with the platinum powder, the cobalt powder, and the nonmagnetic oxide powder to form a mixed powder containing 2 to 15 mol% of nonmagnetic oxide, 3 to 20 mol% of chromium metal, and 5 to 30 mol% of platinum metal, and then add Pressure sintering, the target prepared by this method uses less particles generated during the sputtering process, and the content of the chromium oxide agglomerate (aggregate) in the substrate with an absolute maximum length exceeding 5 μm is in the target. 500 / mm ² or less, and the non-magnetic oxide may be any of cerium oxide, titanium oxide, cerium oxide, aluminum oxide, magnesium oxide, cerium oxide, zirconium oxide, cerium oxide, and cerium oxide.

However, if a pre-alloyed powder is used as a raw material as described above, and a cobalt-chromium-platinum-based alloy sputtering target containing cobalt oxide is to be prepared, the formation of a chromium oxide agglomerate cannot be effectively avoided, indicating that the method is not effective. Solve the problems of the prior art.

In view of the fact that it is difficult to prepare a cobalt-chromium-platinum-based alloy target containing cobalt oxide and non-magnetic oxide which can effectively overcome the phenomenon of arc discharge and particle generation, the present inventors have provided a cobalt-containing and non-cobalt-containing alloy. A cobalt-chromium-platinum-based alloy of magnetic oxide is sputtered to solve the problems of the prior art.

To achieve the above object, the present invention provides a cobalt-chromium-platinum-based alloy sputtering target comprising cobalt oxide and a non-magnetic oxide, which comprises cobalt, chromium, platinum, cobalt oxide and a non-magnetic oxide, wherein the target The maximum absolute length of the ceramic phase containing Cr ₂ O ₃ and Co(Cr)-XO is less than 3 μm, wherein X represents a metal element in the composition of the non-magnetic oxide.

Preferably, the non-magnetic oxide composition may be ceria, titania, cerium oxide or a combination thereof.

Preferably, the sputtering target further comprises an element such as tantalum (Ta), copper (cop), boron (boron, B) or a mixture thereof.

The invention further provides a method for producing a cobalt-chromium-platinum-based alloy sputtering target containing cobalt oxide and a non-magnetic oxide, which comprises: providing a raw material powder substantially consisting of a prealloy containing 20 to 80 at% chromium a powder, a cobalt monoxide (CoO) powder, and a mixture comprising an oxide, wherein the oxide-containing mixture comprises one or more non-magnetic oxide powders, cobalt powders, and platinum powders; Forming to form an initial embryo; subjecting the initial embryo to pressure sintering to obtain the sputtering target.

According to the invention, the term "essentially consisting of" means that a material consists essentially of the specified substance, but which contains other inevitable impurities. In particular, the raw material powder is mainly composed of 20 to 80 at% of a prealloyed powder formed of chromium and other elements, a cobalt monoxide powder, and a mixture containing an oxide, including other unavoidable impurities. (impurities).

According to the present invention, the composition of the prealloyed powder may comprise a powder of cobalt chromium alloy (CoCr), cobalt platinum alloy (CoPt) or cobalt chromium platinum alloy (CoCrPt) or a combination thereof.

Preferably, the preliminary embryo is subjected to a pressure sintering step by subjecting the blast to pressure sintering at a temperature of 850 ° C to 1050 ° C.

Preferably, the non-magnetic oxide powder may be composed of a powder of cerium oxide (SiO ₂ ), titanium oxide (TiO ₂ ), cerium oxide (Ta ₂ O ₅ ) or a combination thereof.

The invention prepares a target by adjusting each metal component in the prealloyed powder to an appropriate ratio and controlling the parameters of the sintering process, and the obtained target contains ceramics of Cr ₂ O ₃ and Co(Cr)-XO. The maximum absolute length of the phase is less than 3 microns, which can effectively improve the problems of arc discharge and particle generation, and can make the composition of the target more uniform, which is beneficial to the film used in the preparation of the recording layer of the magnetic recording medium.

The cobalt-chromium-platinum-based alloy sputtering target containing cobalt oxide and non-magnetic oxide of the present invention comprises cobalt, chromium, platinum, cobalt oxide and non-magnetic oxide, wherein the target contains Cr ₂ O ₃ and Co The maximum absolute length of the ceramic phase of (Cr)-XO is less than 3 μm, wherein X represents a metal element in the composition of the non-magnetic oxide, wherein the non-magnetic oxide composition may be made of cerium oxide, titanium dioxide or cerium oxide. Or a combination thereof. The cobalt chrome-platinum-based alloy sputtering target containing cobalt oxide and non-magnetic oxide of the present invention can be produced by the following method, comprising: providing a raw material powder substantially consisting of a prealloyed powder containing 20 to 80 at% chromium; And a mixture of oxides comprising oxides, one or more non-magnetic oxide powders, cobalt powders and platinum powders, wherein the non-magnetic oxide powders are oxidizable a powder of cerium, titanium dioxide, cerium oxide or a combination thereof; preforming the raw material powder to form an initial embryo; subjecting the blast to pressure sintering, especially at a temperature of 850 ° C to 1050 ° C Sintering is preferred to obtain the sputter target. The technical means used by the present invention for the purpose are further explained below in conjunction with the drawings and preferred embodiments.

Example

Comparative Example 1: Preparation of atomic percentage content of Co-12Cr-5Pt-8 (TiO ₂ Target

Preparation of 88.4 g of cobalt powder (powder particle size 7 μm), 18.8 g of chromium powder (powder particle size 20 μm), 19.5 g of platinum powder (powder particle size 8 μm) and 12.78 g of titanium dioxide powder (powder particle size 10 Micron); mixing the aforementioned powders and grinding them in an automatic grinder for about 30 minutes, and then sieving them with a mesh of 60 mesh; the sieved powder mixture is uniformly filled in the graphite mold, and then the hydraulic press [Pressure of about 300 psi] to form an initial embryo; the original embryo is placed in a hot press furnace together with a graphite mold for sintering, and the hot pressing temperature of the sintering process is 1150 ° C, heat The pressing time was 180 minutes and the pressure was 362 Bar. The target was obtained after sintering was completed.

Referring to Figure 1, the scanning electron microscope (model Hitachi N-3400 SEM) is used to analyze the metallographic map of the target after hot pressing, and it is obvious that almost no chromium oxide agglomerate is formed, and only A ceramic phase containing titanium.

Comparative Example 2: Preparation of atomic percentage content of Co-17Cr-18Pt-4 (TiO ₂ ) -7CoO target

Prepare 63.64 grams of cobalt powder (powder size 7 microns), 17.68 grams of chromium powder (powder size 20 microns), 70.24 grams of platinum powder (powder size 8 microns), 6.4 grams of titanium dioxide powder (powder size 10 Micron) and 10.5 g of one of cobalt oxide powder (powder particle size 8 μm); the aforementioned powders are mixed and ground in an automatic grinder for about 30 minutes, and then sieved using a 60 mesh screen; the sieved After the powder mixture is uniformly filled in the graphite mold, it is pre-formed by a hydraulic press (pressure of about 300 psi) to form an initial embryo; the initial embryo and the graphite mold are placed together in a hot press furnace for sintering, and the sintering process is performed. The hot pressing temperature was 1150 ° C, the hot pressing time was 180 minutes, and the pressure was 362 Bar. The target was obtained after sintering was completed.

Referring to Figure 2, the metallographic map of the target after hot pressing sintering is analyzed by a scanning electron microscope (Model Hitachi N-3400 SEM) and analyzed by image analysis software (Model Image-Pro 6.3). The metal phase and all the ceramic phases containing Cr ₂ O ₃ and Cr-Ti-O, and then the software is used to statistically calculate the size average and standard deviation of the ceramic phase containing Cr ₂ O ₃ and Cr-Ti-O. It can be clearly seen from Fig. 2 that a large number of thick strips of Cr ₂ O ₃ agglomerates are formed, and the average length of the ceramic phase containing Cr ₂ O ₃ and Cr-Ti-O is 3.64 ± 2.89 μm, indicating The maximum absolute length of the ceramic phase containing chromium oxide in the target has been greater than 3 microns.

Comparative Example 3: Preparation of atomic percentage content of 64Co-12Cr-7Pt-8 (TiO ₂ ) -9CoO target

Prepare 63.86 grams of cobalt powder (powder size 7 microns), 23.94 grams of 45Co-55Cr prealloyed powder (powder size 10 microns to 100 microns), 27.32 grams of platinum powder (powder size 8 microns) and 12.76 grams of titanium dioxide Powder (powder particle size 10 μm) and 13.48 g of one of cobalt oxide powder (powder particle size 8 μm); the above powders were mixed and ground in an automatic grinder for about 30 minutes, and then sieved using a 60 mesh screen After the sieved powder mixture is uniformly filled in the graphite mold, it is pre-formed by a hydraulic press (pressure of about 300 psi) to form an initial embryo; the initial embryo and the graphite mold are placed together in a hot press furnace The sintering was carried out, and the hot pressing temperature of the sintering process was 1150 ° C, the hot pressing time was 180 minutes, and the pressure was 362 Bar. The target was obtained after the sintering was completed.

Please refer to Figure 3, which uses a scanning electron microscope (model Hitachi N-3400 SEM) to analyze the metallographic map of the target after hot pressing, and analyze the target using image analysis software (Model Image-Pro 6.3). sheet metal phase containing all sizes of Cr ₂ O ₃ and the Co-Ti-O ceramic phase, the software then statistically calculated ₂ O ₃ and the average value and standard dimensions containing Cr Co-Ti-O ceramic phase of difference. It is apparent from Fig. 3 that a large number of thick strips of Cr ₂ O ₃ agglomerates are formed, and the average length of the ceramic phase containing Cr ₂ O ₃ and Co-Ti-O is 3.64 ± 2.89 μm, indicating the target The maximum absolute length of the ceramic phase containing chromium oxide in the material is already greater than 3 microns.

Example 1: Preparation of an atomic percentage of 64Co-12Cr-7Pt-8 (TiO ₂ ) -9CoO target

Prepare 63.86 grams of cobalt powder (powder size 7 microns), 23.94 grams of 45Co-55Cr prealloyed powder (powder size 10 microns to 100 microns), 27.32 grams of platinum powder (powder size 8 microns) and 12.76 grams of titanium dioxide Powder (powder particle size 10 μm) and 13.48 g of one of cobalt oxide powder (powder particle size 8 μm); the above powders were mixed and ground in an automatic grinder for about 30 minutes, and then sieved using a 60 mesh screen After the sieved powder mixture is uniformly filled in the graphite mold, it is pre-formed by a hydraulic press (pressure of about 300 psi) to form an initial embryo; the initial embryo and the graphite mold are placed together in a hot press furnace The sintering was carried out, and the hot pressing temperature of the sintering process was 1050 ° C, the hot pressing time was 180 minutes, and the pressure was 362 Bar. The target was obtained after the sintering was completed.

Please refer to Figure 4, which uses a scanning electron microscope (model Hitachi N-3400 SEM) to analyze the metallographic map of the target after hot press sintering, and analyze the target using image analysis software (Model Image-Pro 6.3). sheet metal phase containing all sizes of Cr ₂ O ₃ and the Co-Ti-O ceramic phase, the software then statistically calculated ₂ O ₃ and the average value and standard dimensions containing Cr Co-Ti-O ceramic phase of difference. It is apparent from Fig. 4 that the amount of formation of Cr ₂ O ₃ agglomerates in the target has been greatly reduced, and the ceramic phase contained in the target is mainly a ceramic phase of Co-Ti-O. The average length of the ceramic phase containing Cr ₂ O ₃ and Co-Ti-O was 1.29 ± 0.94 μm, indicating that the maximum absolute length of the ceramic phase containing chromium oxide in the target was less than 3 μm.

In summary, the present invention prepares a cobalt-chromium-platinum-based alloy sputtering target by adjusting each metal component in the pre-alloyed powder to an appropriate ratio and controlling the temperature parameter of the sintering process. The maximum absolute length of the ceramic phase containing Cr ₂ O ₃ and Co(Cr)-XO is less than 3 μm, and the amount of chromium oxide agglomerates is also significantly reduced, thereby reducing the target during sputtering. The arc discharges and produces particles and the like, and the composition of the target is more evenly distributed, which is advantageous for the application of the film in the recording layer of the magnetic recording medium.

Fig. 1 is a metallographic diagram of a target obtained in Comparative Example 1 of the prior art.

Fig. 2 is a metallographic view of a target obtained in Comparative Example 2 of the prior art.

Fig. 3 is a metallographic view of a target obtained in Comparative Example 3 of the prior art.

Fig. 4 is a metallographic view of a target obtained in Example 1 of the present invention.

Claims (12)

A cobalt-chromium-platinum-based alloy sputtering target comprising cobalt oxide and a non-magnetic oxide, comprising cobalt, chromium, platinum, cobalt oxide and a non-magnetic oxide, wherein the target contains Cr ₂ O ₃ and Co The maximum absolute length of the ceramic phase of (Cr)-XO is less than 3 microns, wherein X represents the metal element in the composition of the non-magnetic oxide. The target of claim 1, wherein the non-magnetic oxide composition is cerium oxide, titanium dioxide, cerium oxide or a combination thereof. The target according to claim 1 or 2, further comprising bismuth, copper, boron or a mixture thereof. A method for producing a cobalt-chromium-platinum-based alloy sputtering target containing cobalt oxide and a non-magnetic oxide, comprising: providing a raw material powder substantially consisting of a prealloyed powder containing 20 to 80 at% of chromium, cobalt monoxide a powder, and a mixture comprising an oxide, wherein the oxide-containing mixture comprises one or more non-magnetic oxide powders, cobalt powder, and platinum powder; the raw material powder is preformed to form an initial embryo; The priming is subjected to pressure sintering at a temperature of 850 ° C to 1050 ° C to obtain the sputtering target. The manufacturing method of claim 4, wherein the prealloyed powder comprises a powder of a cobalt chromium alloy, a cobalt platinum alloy, a cobalt chromium platinum alloy, or a combination thereof. The manufacturing method according to claim 5, wherein the prealloyed powder further comprises a powder of cerium, copper, boron or a mixture thereof. The manufacturing method according to any one of claims 4 to 6, wherein The non-magnetic oxide powder is composed of a powder of ceria, titania, cerium oxide or a combination thereof. A cobalt-chromium-platinum-based alloy sputtering target comprising cobalt oxide and a non-magnetic oxide, which is produced by a manufacturing method according to any one of claims 4 to 7. The target material according to claim 8, wherein the ceramic phase containing Cr ₂ O ₃ and Co(Cr)-XO has a maximum absolute length of less than 3 μm, wherein X represents a metal in the non-magnetic oxide. element. The target of claim 8, wherein the non-magnetic oxide composition is cerium oxide, titanium dioxide, cerium oxide or a combination thereof. The target of claim 9, wherein the non-magnetic oxide composition is cerium oxide, titanium dioxide, cerium oxide or a combination thereof. The target according to any one of claims 8 to 11, which further comprises bismuth, copper, boron or a mixture thereof.