KR100494610B1 - High-Density Sputtering Target for Forming High-Dielectric Films - Google Patents

Abstract

Provided is a high-density sputtering target for forming a high dielectric film, in which sputtering and uniformity do not occur even at high power.

In the high-density sputtering target for forming a high dielectric film composed of a BaTi composite oxide sintered body, an SrTi composite oxide sintered body, or a BaSrTi composite oxide sintered body having a density ratio of at least 95.1%, the S content contained therein is limited to 50 ppm or less, or the C content The content is limited to 300 ppm or less, or S content is limited to 50 ppm or less and C content is limited to 300 ppm or less.

Description

High-Density Sputtering Target for Forming High-Dielectric Films}

The present invention relates to a high density sputtering target for forming an intrinsic whole film in which flaky peeling or uniformity does not occur even at high speed film formation.

Generally, Ba and Ti composite oxides (hereinafter referred to as BaTi composite oxides), Sr and Ti composite oxides (hereinafter referred to as SrTi composite oxides) and Ba, Sr and Ti composite oxides (hereinafter referred to as BaSrTi composite oxides). A sputtering target made of a sintered body is used as a target for forming a thin film for a capacitor such as a semiconductor memory, and a high dielectric film made of BaTi composite oxide, SrTi composite oxide, or BaSrTi composite oxide obtained by sputtering the target is all perovskite. It is known to have a structure.

In order to prepare a sputtering target for forming a high dielectric film comprising the BaTi composite oxide sintered body, the SrTi composite oxide sintered body or the BaSrTi composite oxide sintered body, firstly, BaCO ₃ powder, SrCO ₃ powder and TiO ₂ powder which are raw powders are prepared. These raw material powders are blended in a predetermined ratio, put into a ball mill and mixed, and the obtained mixed powder is put into an MgO crucible and calcined under conditions maintained at a temperature of 1200 to 1350 ° C. for 3 to 10 hours, followed by a ball mill. By grinding, BaTi composite oxide powder, SrTi composite oxide powder or BaSrTi composite oxide powder is produced.

After the BaTi composite oxide powder, SrTi composite oxide powder, or BaSrTi composite oxide powder was repeatedly subjected to baking and pulverization under the above conditions two or more times, the degree of vacuum was 1 × 10 ⁻⁴ to 5 × 10 ⁻⁴ , and the load was 150 to 200 kg. BaTi composite oxide sintered body, SrTi composite oxide sintered body, or BaSrTi composite oxide sintered body are manufactured by hot-pressing on the conditions maintained at / cm <^2> , temperature 900-1200 degreeC, and 0.5 to 3 hours, These BaTi composite oxide sintered body and SrTi composite oxide sintered body Alternatively, the BaSrTi composite oxide sintered body may be machined to be completed into a target having a predetermined shape.

When inevitable impurities such as Na or Ca and further Al, Si, and Fe contained in the target thus obtained are set to 90 ppm or less, cracks do not occur during sputtering even with large diameter targets having a diameter of 200 to 500 mm. See publication 7-3444).

In recent years, it is desired to form a high dielectric film in a short time by sputtering at high output using a large-scale target and forming a high speed film for mass production of semiconductor memories and cost reduction. To this end, the target is further densified to increase the strength and thermal conductivity, thereby forming a high speed film. According to the conventional high density sputtering target, if the high speed film is formed at a film formation rate of 100 μs / min or more, the target surface is sputtered. The flaky peeling or the entire target may be cracked, and if the conventional densified sputtering target is manufactured by hot pressing, cracking may occur due to hot press rising, and the density ratio of the conventional sputtering target is avoided. Had to be kept below 95%.

Therefore, the inventors of the present invention have developed a sputtering target for forming a high-k dielectric film composed of a high-density sintered body having a density ratio of 95.1% or more that does not cause cracking and peeling even when forming a high-speed sputtering film at high power, and furthermore, no cracking occurs during the production of the sputtering target. By doing research, the following facts were found.

In the crack of the sputtering target for forming the high dielectric film composed of the high density sintered compact, S and C have a great influence among the unavoidable impurities included in the target.

(a) In order to prevent cracking and delamination during high-speed sputtering film formation of the high-density sputtering target for forming a high-density high-k dielectric film having a density ratio of 95.1% or more, the S component contained in the target should be as small as possible, and the S content should be 50 ppm or less. By suppressing, the crack and peeling at the time of high-speed film formation of the high-density sputtering target for high dielectric film formation of a density ratio 95.1% or more can be eliminated.

(b) Conventionally, commercially available Ba carbonate powder, Sr carbonate powder and Ti oxide powder were used as raw material powders for the production of high density sputtering targets for forming a high dielectric film. However, commercially available Ba carbonate powder and Sr carbonate powder have sulfur content of 80 When high density sputtering targets for high dielectric film formation are prepared using Ba carbonate powder and Sr carbonate powder containing not less than ppm and containing 80 ppm or more of sulfur components, cracks may occur due to hot press rise during sputtering target production. Therefore, it is better to have as few sulfur components as possible in the raw material powder, and it is necessary to suppress S to 50 ppm or less.

(C) Since the sulfur content contained in commercially available Ti oxide powder is very small and 5 ppm or less, commercially available Ti oxide powder can be used as a raw material powder as it is.

(d) Since the sputtering target for forming a high dielectric film includes about 500 to 1000 ppm of carbon, the sputtering target for forming a conventional high dielectric film is used as it is and has a high density sputtering target having a density ratio of 95.1% or more. When high-speed sputtering occurs, cracks and peelings occur during film formation, and in order to eliminate this, it is necessary to reduce C content in the high-density film-forming high-density sputtering target as little as possible to suppress C to 300 ppm or less.

(e) BaTi composite oxide powder, SrTi composite oxide powder, and the like are fired by firing commercially available Ba carbonate powder, Sr powder and Ti oxide powder in order to suppress C content contained in the high-density sputtering target for forming a high dielectric film to 300 ppm or less; Even if a BaSrTi composite oxide powder is produced, C remains in 500 to 1000 ppm. Therefore, in order to reduce C, it is necessary to sift to 100 µm or less after pulverization and then calcinate at 1000 to 1200 ° C. for 2 to 5 hours in the atmosphere.

(f) The high-density sputtering target for forming the high-k dielectric film is less than S: 50 ppm and less than C: 300 ppm, which makes it possible to more effectively eliminate cracks and peeling at the time of sputtering high-speed film formation, and furthermore, hot press at the time of manufacturing the sputtering target. The crack in a rise can be prevented.

(g) A sputtering target having an S content of 50 ppm or less and a C content of 300 ppm or less firstly reduces the S component of commercially available Ba carbonate powder and Sr powder, which is a raw material powder, to 50 ppm or less, and then reduces the S component to 50 ppm or less. BaTi composite oxide powder, SrTi composite oxide powder or BaSrTi composite oxide powder was prepared by firing the obtained Ba carbonate powder and Sr carbonate powder together with commercially available Ti oxide powder having S 5 ppm or less, and the composite oxide powder was lower than the sintering temperature. It can be manufactured by maintaining for a long time at and removing C contained in these BaTi composite oxide powder, SrTi composite oxide powder or BaSrTi composite oxide powder, and hot pressing these carbon-removed composite oxide powder at high temperature and high pressure.

The present invention has been made on the basis of this knowledge,

(1) A high-density sputtering target for forming a high-k dielectric film in which a S content is limited to 50 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti,

(2) A high-density sputtering target for forming a high-k dielectric film in which a high S content is limited to 50 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a composite oxide of Sr and Ti,

(3) A high-density sputtering target for forming a high-k dielectric film, in which a S content is limited to 50 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba, Sr, and Ti,

(4) A high-density sputtering target for forming a high-k dielectric film in which a S content is limited to 300 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti,

(5) A high-density sputtering target for forming a high-k dielectric film, in which a high C film content is limited to 300 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a composite oxide of Sr and Ti,

(6) A high-density sputtering target for forming a high-k dielectric film in which a high C film is limited to 300 ppm or less in a high-k dielectric film-forming sputtering target composed of a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba, Sr, and Ti,

(7) A high-density film-forming high-density film-forming sputtering target composed of a high density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, wherein the S content is 50 ppm or less and the C content is 300 ppm or less. Sputtering target,

(8) A high-density dielectric film-forming sputtering target composed of a high-density sintered body composed of a high density sintered body having a density ratio of 95.1% or more composed of a composite oxide of Sr and Ti, wherein the high-density dielectric film formation density is limited to 50 ppm or less and C content of 300 ppm or less. Sputtering target,

(9) In the sputtering target for forming a high-k dielectric film composed of a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba, Sr, and Ti, the formation of a high-k dielectric film having a S content of 50 ppm or less and a C content of 300 ppm or less High density sputtering target

It is characterized by.

Since the S content contained in the high density target greatly affects the cracking and peeling of the high density target during high power sputtering, it is preferable to use as little as possible. If the content is higher than 50 ppm, the cracking and peeling of all the high density targets during the high power sputtering occurs. Not desirable Therefore, content of S was set to 50 ppm or less. The more preferable range of S content is 20 ppm or less. In addition, the C content in the high-density target has a smaller effect on the cracking and peeling of the high-density target during high-power sputtering than S, but is preferably as small as possible. When the content is higher than 300 ppm, all the high-density targets during high-power sputtering are cracked and peeled. Is not desirable because it occurs. Therefore, the C content was set at 300 ppm or less. The more preferable range of C content is 100 ppm or less.

In order to reduce the S content of the Ba carbonate powder to 50 ppm or less, commercially available Ba carbonate powder is calcined in the air at a temperature of 1250 to 1350 ° C., decomposed into BaO and carbon dioxide gas, and then water is applied to BaO to (OH) ₂ solution was prepared, and the S component was separated by filtration in the form of a BaSO ₄ compound, followed by Ba (OH) ₂ solution. It can manufacture by passing a carbon dioxide gas. In addition, in order to reduce the S content of the Sr carbonate powder to 50 ppm or less, commercially available Sr powder is calcined in the air at a temperature of 1250 to 1350 ° C., decomposed into SrO and carbonic acid gas, and then water is acted on the SrO to obtain Sr. (OH) ₂ solution can be prepared, and the S component can be prepared by filtration and separation in the form of SrSO ₄ compound, and then passing carbon dioxide gas through the Sr (OH) ₂ solution.

For forming the high dielectric film of the present invention comprising a high-density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, a complex oxide of Sr and Ti, or a complex oxide of Ba, Sr, and Ti having an S content of 50 ppm or less In order to manufacture a high-density sputtering target, Ba carbonate powder, Sr carbonate powder and commercially available Ti oxide powder in which the S content is reduced to 50 ppm or less are used, and the powder is mixed at a predetermined ratio in the atmosphere at 1250 to 1350 ° C. The BaTi composite oxide powder, SrTi composite oxide powder, or BaSrTi composite oxide powder, each having an S content of 50 ppm or less, was calcined at a temperature condition of 1, and the BaTi composite oxide powder, SrTi composite oxide powder, or BaSrTi composite oxide powder was prepared at a vacuum degree of 1 x. 10 ^-4 to 5 x 10 ^-5, load: 150 to 200 kg / ㎠, a temperature from 1250 to 1350 ℃, 0.5 to 3 hours maintaining BaTi clothing by hot press on the condition that The oxide sintered body, it is possible to process composite oxide sintered compact or SrTi BaSrTi producing a composite oxide sintered body, and these machines BaTi composite oxide sintered compact, SrTi composite oxide sintered compact or BaSrTi composite oxide sintered to produce a target having a predetermined shape.

For forming the high dielectric film of the present invention composed of a high density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, a complex oxide of Sr and Ti, or a complex oxide of Ba, Sr, and Ti having a C content of 300 ppm or less In order to manufacture a high-density sputtering target, commercially available Ba carbonate powder, Sr carbonate powder and commercially available Ti oxide powder are mixed at a predetermined ratio and calcined at a temperature condition of 1250 to 1350 ° C. in the air to produce BaTi composite oxide powder and SrTi composite oxide powder. Alternatively, BaSrTi composite oxide powders are prepared, and these BaTi composite oxide powders, SrTi composite oxide powders, or BaSrTi composite oxide powders are further removed in the air at a temperature lower than the sintering temperature at 1000 to 1200 ° C. for 2 to 5 hours to remove carbon. BaTi composite oxide powder, SrTi composite oxide powder or BaSrTi composite acid BaTi composite oxide sintered body, SrTi composite oxide sintered body by hot-pressing the cargo powder under the conditions of 0.5 to 3 hours at a vacuum degree of 1 x 10 ^-4 to 5 x 10 ^-5 , a load of 150 to 200 kg / cm 2, and a temperature of 1250 to 1350 ° C. for 0.5 to 3 hours. A BaSrTi composite oxide sintered body can be produced, and these targets can be manufactured by machining the BaTi composite oxide sintered body, the SrTi composite oxide sintered body, or the BaSrTi composite oxide sintered body.

When commercially available BaTi composite oxide powder, SrTi composite oxide powder, or BaSrTi composite oxide powder containing 500 to 1000 ppm of carbon is used as the raw powder, the cause of cracking due to hot press rise is that sintering proceeds from the surroundings to the center. Therefore, it is considered that the CO gas generated in the center portion of the sintered compact loses its escape and breaks the sintered compact.

<Example 1>

A commercially available Ba carbonate powder having a purity of 99.9% was prepared and S content was measured, and S 150 ppm was contained. After these, the commercially available air carbonate Ba powder having a purity of 99.9% are then fired at a temperature of 1300 ℃ decomposed into BaO and carbon dioxide to react with water in the BaO to prepare a Ba (OH) ₂ solution, BaSO ₄ ^`compound After filtration and separation in the form, ultra-low sulfur BaCO ₃ powder having an S content of 20 ppm was prepared by passing a carbon dioxide gas through the Ba (OH) ₂ solution.

A commercially available S9.9 carbonate powder having a purity of 99.9% was prepared, and the S content thereof was measured. S100 ppm was contained. After these, the commercially available air carbonate Sr powder having a purity of 99.9% are then fired at a temperature of 1300 ℃ digested with SrO and carbon dioxide to react with water to SrO Sr (OH) to prepare a _second solution, and SrSO ₄ compound After filtration and separation, ultra low sulfur SrCO ₃ powder having an S content of 10 ppm was prepared by passing a carbon dioxide gas through the Sr (OH) ₂ solution.

A commercially available TiO ₂ powder (S content: less than 5 ppm) was also prepared as a raw material powder.

These refined ultra-low sulfur BaCO ₃ powder, SrCO ₃ powder and TiO ₂ powder are blended in a predetermined ratio, put into a ball mill with a ball made of YSZ, and mixed, and the obtained mixed powder is calcined under the condition of maintaining at 1200 ° C for 1 hour in the air. by _{BaTiO 3, SrTiO 3 (Ba 0.75} , Sr 0.25) TiO 3, (Ba 0.5, Sr 0.5) TiO 3 and (Ba _0.25, Sr _0.75) to produce a very low sulfur compound oxide consisting of TiO _3.

These ultra-low sulfur composite oxides were put into a ball mill and pulverized, and BaTiO ₃ having an average particle diameter of 1 to 10 µm was obtained. A very low sulfur complex oxide powder made of powder, SrTiO ₃ powder, (Ba _0.75, Sr _0.25 ) TiO ₃ powder, (Ba _0.5 , Sr _0.5 ) TiO ₃ powder and (Ba _0.25 , Sr _0.75 ) TiO ₃ powder was prepared, and again The obtained ultra-low sulfur composite oxide powder was filled into a graphite mold

 Temperature rise rate: 5 ℃ / min

 Heating temperature: 1300 ℃

 Pressure: 150ton / ㎠

 Retention time: 1 hour

 Cooling: furnace cooling

The hot press sintered body of the density ratio shown in Table 1 was manufactured by hot-pressing on condition of, and the high density sputtering target of this invention which has a diameter of 300 mm and a thickness of 5 mm by grinding this hot press sintered body (henceforth a target of this invention) 1 to 5 were produced.

Table 1 shows the S content of the targets 1 to 5 of the present invention.

These targets 1 to 5 of the present invention were hot pressed 10 times with the same raw material to measure the number of successes of the hot pressed target without cracking, and the results are shown in Table 1. Subsequently, the hot-pressed target without cracking is joined to the water-cooled copper plate by In-Sn solder and set in a high frequency magnetron sputtering device,

Atmosphere gas: Mixed gas of Ar and oxygen (Ar: 0 = 1: 1)

Atmosphere pressure: 1Pa

Frequency: 13.56Mhz

Output: 6000W

Time: 50 hours

The sputtering was carried out under the conditions of and visually observed whether flaky peeling or cracking occurred in the target, and the results are also shown in Table 1.

Comparative Example 1

Commercially available BaCO ₃ powders, SrCO ₃ powders and TiO ₂ powders prepared in Examples were mixed together, mixed and calcined to BaTiO ₃ , SrTiO _3. (Ba _{0 .75, 0 .25} Sr) TiO _3, (Ba _{0 .5, 0 .5} Sr) TiO ₃ and _{(Ba 0.25, Sr 0 .75)} TiO 3 to prepare a complex oxide made of, and the complex oxide The hot pressed sintered body having the density ratio shown in Table 1 was prepared by hot pressing the pulverized powder obtained by pulverizing under the same conditions as in the examples, and grinding it to obtain a comparative high density sputtering target having a diameter of 300 mm and a thickness of 5 mm (hereinafter, 1 to 5) were prepared. The S content contained in the comparative targets 1 to 5 obtained was measured and hot pressed 10 times with the same raw material to measure the number of successes of the hot pressed target without cracking, and again the hot pressed target without cracking. It sputter | spattered on the conditions similar to an Example, and it observed visually whether the flaky peeling or a crack generate | occur | produced in the target at that time, and the result was also shown in Table 1.

target Component Compositions of Complex Oxides Comprising Targets S content (ppm) Density Ratio (%) Number of successful shots on hot-pressed targets without cracking Presence of flaky peeling or cracking during sputtering Invention One BaTiO ₃ 8 99 10/10 radish 2 (Ba _0.75 Sr _0.25 ) TiO ₃ 50 98 10/10 radish 3 (Ba _0.5 Sr _0.5 ) TiO ₃ 40 95.5 10/10 radish 4 (Ba _0.25 Sr _0.75 ) TiO ₃ 10 97 10/10 radish 5 SrTiO ₃ 15 99 10/10 radish compare One BaTiO ₃ 100 98 0/10 - 2 (Ba _0.75 Sr _0.25 ) TiO 70 99 3/10 U 3 (Ba _0.5 Sr _0.5 ) TiO ₃ 100 95.5 0/10 - 4 (Ba _0.25 Sr _0.75 ) TiO ₃ 150 97 0/10 - 5 SrTiO ₃ 60 99 2/10 U

From the results shown in Table 1, S content 50 ppm or less obtained using purified SCO content 20 ppm BaCO ₃ powder, S content 10 ppm SrCO ₃ powder, and commercially available TiO ₂ powder (S content less than 5 ppm) The targets 1 to 5 of the present invention having a density ratio of 95.1% or more are S content obtained using commercially available BaCO ₃ powder containing 150 ppm S, SrCO ₃ powder containing S 100 ppm and TiO ₂ powder containing S 5 ppm. Compared with Comparative targets 1 to 5 of 60 ppm or more and a density ratio of 95.1% or more, it was found that cracking did not occur during hot pressing, and flaky peeling or cracking did not occur during sputtering, and high-speed film formation was possible at high power.

<Example 2>

Commercially available BaCO ₃ powders, SrCO ₃ powders and TiO ₂ powders are mixed together, mixed and calcined to obtain BaTiO ₃ powders, SrTiO ₃ powders, (Ba _0.75 , Sr _0.25 ) TiO ₃ powders, (Ba _0.5 , Sr _0.5 ) TiO ₃ A powder and a (Ba _0.25 , Sr _0.75 ) TiO ₃ powder were prepared, and the C content was measured, and the amount of C shown in Table 2 was contained. This BaTiO ₃ powder, SrTiO ₃ powder, (Ba _0.75 , Sr _0.25 ) TiO ₃ powder, (Ba _0.5 , Sr _0.5 ) TiO ₃ powder and (Ba _0.25 , Sr _0.75 ) TiO ₃ powder were sieved to 100 μm or less, Ultra-low carbon composite oxide powder having the component composition shown in Table 2 was prepared by carbon removal treatment by heating under conditions maintained at 1100 ° C. for 1 hour in the air.

Complex oxide powder before carbon removal treatment Ultra low carbon composite oxide powder obtained by carbon removal treatment Ingredient composition Carbon concentration (ppm) Ingredient composition Carbon concentration (ppm) BaTiO ₃ 600 BaTiO ₃ 200 (Ba _0.75 Sr _0.25 ) TiO ₃ 500 (Ba _0.75 Sr _0.25 ) TiO ₃ 100 (Ba _0.5 Sr _0.5 ) TiO ₃ 400 (Ba _0.5 Sr _0.5 ) TiO ₃ 20 (Ba _0.25 Sr _0.75 ) TiO ₃ 800 (Ba _0.25 Sr _0.75 ) TiO ₃ 50 SrTiO ₃ 700 SrTiO ₃ 300

The ultra-low carbon composite oxide powder having a carbon concentration shown in Table 2 obtained by carbon removal treatment was put into a ball mill and pulverized to prepare an ultra-low carbon composite oxide powder having an average particle diameter of 1 to 10 µm, and the ultra-low carbon composite oxide powder thus obtained was again obtained. Fill in the graphite mold

Temperature rise rate: 5 ℃ / min

Heating temperature: 1300 ℃

Pressure: 150ton / ㎠

Retention time: 1 hour

Cooling: furnace cooling

The hot press sintered compact of the density ratio shown in Table 3 was produced by hot pressing on condition of, and the targets 6-10 of this invention which have a diameter of 300 mm and a thickness of 5 mm were produced by grinding the surface of this hot press sintered compact. did. Table 3 shows the C content of the obtained targets 6-10 of this invention.

In addition, 6 to 10 of the target of the present invention was hot pressed five times with the same raw material to measure the number of successes of the hot pressed target without cracking, and the results are shown in Table 3. Subsequently, the hot-pressed target without cracking was joined to the water-cooled copper plate by In-Sn solder and set in a high frequency magnetron sputtering device.

Atmosphere gas: Mixed gas of Ar and oxygen (Ar: 0 = 1: 1)

Atmosphere pressure: 1Pa

Frequency: 13.56Mhz

Output: 6000W

Time: 50 hours

The sputtering was carried out under the condition of, and whether the flaky peeling or cracking occurred in the target was visually observed and the results are also shown in Table 3.

Comparative Example 2

BaTiO ₃ powder, SrTiO ₃ powder, (Ba _0.75 , Sr _0.25 ) TiO ₃ powder, (Ba _0.5 , Sr _0.5 ) TiO ₃ powder and (Ba _0.25 , Sr _0.75 ) TiO ₃ powder before carbon removal treatment shown in Table 2 By hot pressing under the same conditions as in Example 2, a hot press sintered body having a density ratio shown in Table 3 was prepared, and the comparative targets 6 to 10 having dimensions of 300 mm in diameter and 5 mm in thickness were prepared by grinding the hot press sintered body surface. Manufactured. The C content contained in the comparative targets 6 to 10 thus obtained was measured five times with the same raw material to measure the number of successes of the hot pressed target without cracking, and again using the hot pressed target without cracking. Sputtering was carried out under the same conditions as in Example 2, and it was visually observed whether flaky peeling or cracking occurred in the target at that time, and the results are shown in Table 3.

target Component Compositions of Complex Oxides Comprising Targets C content (ppm) Density Ratio (%) Number of successful shots on hot-pressed targets without cracking Presence of flaky peeling or cracking during sputtering Invention 6 BaTiO ₃ 100 97 5/5 radish 7 (Ba _0.75 Sr _0.25 ) TiO ₃ 50 99 5/5 radish 8 (Ba _0.5 Sr _0.5 ) TiO ₃ 40 98 5/5 radish 9 (Ba _0.25 Sr _0.75 ) TiO ₃ 20 99 5/5 radish 10 SrTiO ₃ 290 95.5 5/5 radish compare 6 BaTiO ₃ 600 97 2/5 U 7 (Ba _0.75 Sr _0.25 ) TiO ₃ 450 99 2/5 U 8 (Ba _0.5 Sr _0.5 ) TiO ₃ 400 98 3/5 U 9 (Ba _0.25 Sr _0.75 ) TiO ₃ 750 99 1/5 U 10 SrTiO ₃ 700 95.5 1/5 U

From the results shown in Tables 2 to 3, the composite oxide powders containing C-containing 500 to 1000 ppm, all of the targets 6 to 10 of the present invention having a C content of 300 ppm or less and a density ratio of 95.1% or more, obtained using the ultra low carbon composite oxide. Compared to the comparative targets 6 to 10 with a C content of 400 ppm or more and a density ratio of 95.1% or more, the cracks do not occur during manufacture by hot pressing, and do not peel or crack during sputtering, and high-speed film formation is possible at high output. I could see that.

<Example 3>

The ultra-low sulfur BaCO ₃ powder having an S content of 20 ppm, the ultra low sulfur SrCO ₃ powder having an S content of 10 ppm and the commercially available TiO ₂ powder (S content: less than 5 ppm) obtained in Example 1 were used under the same conditions as in Example 1. An ultra low sulfur composite oxide consisting of BaTiO ₃ , (Ba _0.75 , Sr _0.25 ) TiO ₃ , (Ba _0.5 , Sr _0.5 ) TiO _3, and (Ba _0.25 , Sr _0.75 ) TiO ₃ was prepared.

These ultra-low sulfur composite oxides were put into a ball mill and pulverized to obtain BaTiO ₃ powder, SrTiO ₃ powder, (Ba _0.75 , Sr _0.25 ) TiO ₃ powder, (Ba _0.5 , Sr _0.5 ) TiO ₃ powder having an average particle diameter of 1 to 10 μm, and ( Ba _0.25 , Sr _0.75 ) TiO ₃ powder to prepare ultra-low sulfur composite oxide powder and sift the ultra-low sulfur composite oxide powder to 100㎛ or less, and then remove the carbon by heating under the condition of maintaining at 1100 ℃ in the air for 1 hour The treatment yielded an ultra low carbon sulfur composite oxide powder.

These ultra low carbon sulfur composite oxide powders were filled in a graphite mold

Temperature rise rate: 5 ℃ / min

Heating temperature: 1300 ℃

Pressure: 200tom / cm ²

Retention time: 1 hour

Cooling: furnace cooling

The hot press sintered compact was manufactured by hot-pressing on condition of, and the target 11-15 of this invention which had the dimension of diameter 300mm and thickness 5mm was manufactured by grinding this hot press sintered compact. Table 4 shows S and C content of these targets 11-15 of this invention.

In addition, the targets 11 to 15 of the present invention were hot pressed 15 times with the same raw material to measure the number of successes of the hot pressed target without cracking, and the results are shown in Table 5. Subsequently, the hot-pressed target without cracking is joined to the water-cooled copper plate by In-Sn solder and set in a high frequency magnetron sputtering device,

Atmosphere gas: Mixed gas of Ar and oxygen (Ar: 0 = 1: 1)

Atmosphere pressure: 1Pa

Frequency: 13.56Mhz

Output: 6000W

Time: 50 hours

The sputtering was carried out under the conditions of and visually observed whether flaky peeling or cracking occurred in the target, and the results are also shown in Table 5.

target Component Compositions of Complex Oxides Comprising Targets Density ratio (%) S content in the target (ppm) C content in the target (ppm) Invention 11 BaTiO ₃ 99 8 250 12 (Ba _0.75 Sr _0.25 ) TiO ₃ 99 50 150 13 (Ba _0.5 Sr _0.5 ) TiO ₃ 99 40 50 14 (Ba _0.25 Sr _0.75 ) TiO ₃ 99 10 100 15 SrTiO ₃ 99 15 300

target Component Compositions of Complex Oxides Comprising Targets Number of successful shots on hot-pressed targets without cracking Presence of flaky peeling or cracking during sputtering Invention 11 BaTiO ₃ 15/15 radish 12 (Ba _0.75 Sr _0.25 ) TiO ₃ 15/15 radish 13 (Ba _0.5 Sr _0.5 ) TiO ₃ 15/15 radish 14 (Ba _0.25 Sr _0.75 ) TiO ₃ 15/15 radish 15 SrTiO ₃ 15/15 radish

From the results shown in Tables 4 to 5, targets 11 to 15 of the present invention having a S content of 50 ppm or less, a C content of 30 ppm or less, and a density ratio of 95.1% or more do not crack even when hot presses 15 times with the same raw material. It was found that high-speed film formation can be achieved at high power without being exfoliated or cracked upon sputtering, and the reliability of crack resistance of the target during sputtering is further improved.

As described above, the sputtering target for forming a high dielectric film of the present invention has flaky peeling or sputtering on a sputtering target when forming a high-speed film at a high output despite having a high density ratio of 95.1% or more in order to improve strength and thermal conductivity. It is possible to sputter at high power by using a larger target without cracking, thereby greatly contributing to mass production and cost reduction of semiconductor memory.

Claims (3)

In a sputtering target for forming a high dielectric film composed of a high density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, a complex oxide of Sr and Ti, or a complex oxide of Ba, Sr and Ti, the S content is 50 ppm or less. A high density sputtering target for forming a high dielectric film, characterized in that limited. In a sputtering target for forming a high dielectric film composed of a high density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, a complex oxide of Sr and Ti, or a complex oxide of Ba, Sr and Ti, the C content is 300 ppm or less. A high density sputtering target for forming a high dielectric film, characterized in that limited. In a sputtering target for forming a high dielectric film composed of a high density sintered body having a density ratio of 95.1% or more composed of a complex oxide of Ba and Ti, a complex oxide of Sr and Ti, or a complex oxide of Ba, Sr and Ti, the S content is 50 ppm or less. A high density sputtering target for forming a high dielectric film, which is limited and has a C content of 300 ppm or less.