KR20070028517A - Method for manufacturing target material for sputtering target - Google Patents

Abstract

A method for manufacturing a target material for a sputtering target by powder metallurgy method is provided with a heating process wherein each body to be baked after formation is sintered from one side. In the heating process, each body to be baked is preferably heated by being transferred over two or more adjacent areas set at different temperatures at the same time. In the heating process, by having a difference between temperatures at both ends of one body to be baked while the temperature is increased, the body to be baked can be successively heated and sintered from one side. Therefore, even when manufacturing a matter referred to as a long material or a large target material, since the body to be baked is successively sintered from one side and is successively contracted due to sintering as well, the density of the target material finally obtained can be improved, density nonuniformity can be suppressed and generation of warpage and breakage can be prevented. ® KIPO & WIPO 2007

Description

Manufacturing method of target material for sputtering target {METHOD FOR MANUFACTURING TARGET MATERIAL FOR SPUTTERING TARGET}

The present invention relates to a method for producing a target material of a sputtering target. More specifically, the present invention relates to a method of continuously producing the target material.

Conventionally, the sputtering method is known as one of the thin film formation methods.

As a thin film formed by the sputtering method, the thin film of oxide (ITO; Indium Tin Oxide) which has indium oxide and tin oxide as a main component is mentioned, for example. Since this ITO thin film has the characteristics of high electroconductivity and visible light transmittance, it is widely used for various uses, such as the transparent electrode for flat panel displays, and the anti-condensation heating film for window glass. In particular, in the field of flat panel displays including liquid crystal display devices, the enlargement of displays has become remarkable in recent years, and accordingly, the sputtering targets used for the production of ITO thin films also tend to be enlarged, and the enlargement of target materials is progressing.

The target material of the sputtering target used in the manufacture of such an ITO thin film is usually subjected to a so-called powder metallurgy method in which a binder is added to a raw material powder as desired to compression molding, and the obtained molded product is degreased as necessary, followed by firing to obtain a sintered body. It is manufactured by.

Conventionally, in manufacture of the target material by powder metallurgy, it was common that degreasing and baking are performed in what is called a batch furnace.

As shown in FIG. 2, the batch furnace includes heating means such as a heater 17 at an outer edge of the furnace, and discontinuously inserts the to-be-fired body 21 into the furnace and fires once. Roy. In such a batch furnace 15, in order to increase the production amount, it is common to place the to-be-baked body 21 on the baking plate 19 called a shelf board, and to install what was piled up sequentially in the furnace and to bake.

However, in this arrangement, since the furnace volume is large and the heating means from the outside is employed, the inclination of the temperature distribution in the horizontal direction and the vertical direction in the furnace is increased as shown in FIG. There existed such a difficult, various problem resulting from this, for example, the bending of a target material obtained, a crack, the density of a target material becoming difficult, and a density nonuniformity tends to arise.

These problems were particularly remarkable when the large to-be-baked material was fired in a batch furnace in order to cope with the increase in size of the target material.

In order to solve these problems, examination of the degreasing conditions before baking (refer patent document 1), use of the baking plate at the time of baking, examination of the shape of a baking plate (refer patent document 2), examination of the raw material powder to be used, and temperature or baking Various examinations, such as examination of baking conditions, such as atmosphere (refer patent document 3), the examination of the system of the shelf set in a furnace and the shape of a shelf board, have been made.

However, even with this examination, even heating of the to-be-baked body in the batch furnace is intended to solve the above problem. In the firing by the batch furnace, since the time required for the original firing process is long, the production efficiency is greatly improved. Did not expect. In addition, when the above problem is to be solved by examining the firing conditions, by lowering the temperature raising / lowering speed, providing a temperature holding area for a plurality of times, or lengthening the temperature holding time, There was also a problem that the length of time increased and the running cost increased.

In addition, the sputtering target and the target material are required to have a small oxygen partial pressure dependency upon sputtering with respect to the specific resistance of the thin film formed by sputtering, in addition to the demand for enlargement.

Usually, in sputtering, it is known that the specific resistance of the formed thin film is changed depending on the oxygen partial pressure mixed with an inert gas such as argon, and the amount of oxygen introduced into the sputtering apparatus is controlled so that the specific partial pressure is the oxygen partial pressure which is the minimum. Sputtering is performed.

However, as the size of the sputtering device increases, the control of the amount of introduced oxygen becomes difficult, and the variation in the partial pressure of oxygen occurs. As a result, the variation of the specific resistance of the formed thin film occurs, and the quality of the device using the thin film, in particular, the quality of the liquid crystal display characteristics. There was a problem that it became easy to lower.

In addition, as the use time of the sputtering target (the cumulative time of the sputtering history) becomes longer, it is also known that the optimum oxygen partial pressure changes, but there is a problem that the change in the resistivity of the thin film becomes larger when the oxygen partial pressure dependency is large.

<Patent Document 1> Japanese Patent Application Laid-Open No. 10-330169

<Patent Document 2> Japanese Patent Application Laid-Open No. 2001-122668

<Patent Document 3> Japanese Patent Application Laid-Open No. 09-228036

[Initiation of invention]

[Problem to Solve Invention]

An object of the present invention is to provide a method for producing a high quality sputtering target target material in a short time with good production efficiency.

Moreover, an object of this invention is to provide the method of manufacturing the target material for sputtering targets with small dependence of oxygen partial pressure at the time of sputtering with respect to the specific resistance of the thin film formed by sputtering.

[Means for solving the problem]

The manufacturing method of the target material which concerns on this invention is a method of manufacturing the target material of a sputtering target by the powder metallurgy method, Comprising: It has a heating process which sinters the to-be-baked material from one side with respect to each to-be-baked material. It features.

It is preferable that the said heating process is a process of heating the to-be-baked material so that the both ends may have a temperature difference with respect to per said to-be-baked material.

Specifically, it is preferable that the heating step is a step of heating the object to be fired while simultaneously covering two or more adjacent areas set at different temperatures, per one object to be fired.

It is more preferable that it is a process of heating, conveying the said to-be-baked body so that it may cover 2 or more adjacent areas set to different temperature simultaneously with respect to each said to-be-baked body.

In the said heating process, the temperature of each area | region of the said 2 or more area | regions is respectively set so that it may become sequentially high as it goes to a conveyance direction within the range of 10-500 degreeC compared with the temperature of the area | region adjacent to each other among these, Moreover, it is preferable that the conveyance speed of the to-be-baked material which passes through these two or more area | regions is 1-50 mm / min.

Moreover, in the said heating process, it is preferable that the setting temperature of the region with the lowest temperature among the said 2 or more area | regions exists in the range of room temperature-800 degreeC.

Moreover, in this invention, in addition to the said heating process, it is preferable to have the cooling process of cooling the to-be-baked material so that the both ends may have a temperature difference with respect to each to-be-baked material after a heating process.

Specifically, it is preferable that the cooling step is a step of cooling while simultaneously covering two or more adjacent areas set to different temperatures with respect to one object to be baked after the heating step,

It is more preferable that it is a process of cooling, conveying the to-be-baked material so that it may spread over two or more adjacent areas | regions set to different temperature simultaneously with respect to each to-be-baked material after a heating process.

In the cooling step, the temperatures of the respective regions of the two or more regions are set so as to be sequentially lowered toward the conveyance direction within the range of 10 to 500 ° C, compared with the temperatures of the regions adjacent to each other among them, Moreover, it is preferable that the conveyance speed of the to-be-baked material which passes through these two or more area | regions is 1-50 mm / min.

Moreover, in the said cooling process, it is preferable that the setting temperature of the region with the highest temperature among the said 2 or more area | regions exists in the range of 1300-1800 degreeC.

Moreover, in the manufacturing method of the target material of this invention, it is preferable to perform the said heating process in a continuous furnace, and it is more preferable to perform the said heating process and a cooling process in a continuous furnace.

Moreover, it is preferable to have heating means up and down on the conveyance path of a to-be-baked body, and, as for the said continuous furnace, it is more preferable that it is a roller hearth kiln.

It is also preferable to introduce oxygen into the continuous furnace. In this case, the flow rate of oxygen introduced into the continuous furnace is preferably an amount within the range of 0.1 to 500 m ³ / h.

Moreover, in this invention, it is preferable that the said target material is the target material for transparent conductive film formation. It is more preferable that it is an oxide mainly having indium oxide, tin oxide, and zinc oxide as a main component, and it is still more preferable that it is an oxide (ITO) which has indium oxide and tin oxide as a main component.

[Effects of the Invention]

According to the present invention, in the heating step, since the temperature difference between the two to-be-baked bodies has a temperature difference between both ends at the time of temperature rising, it can be heated sequentially from one side and sintered, so that a so-called long object and a large target material are produced. In this case, sintering occurs sequentially from one side of the to-be-fired body, and shrinkage due to sintering of the to-be-fired body also proceeds sequentially, so that the density of the finally obtained target material can be improved, and the density nonuniformity can be improved, and the warpage and cracking are also performed. Can also be prevented.

Moreover, in this invention, in order to perform such baking processing, it discovered that what is called a continuous furnace which heats, or heats and cools, conveying the to-be-baked body to the area | region set to different temperature is good. Moreover, in this method, since the baking process can be performed continuously, the baking process time required per unit quantity of the target material can be shortened, and a high quality target material can be manufactured with high production efficiency.

Moreover, according to this invention, the target material for sputtering with small dependence of oxygen partial pressure at the time of sputtering with respect to the specific resistance of the thin film formed by sputtering can be manufactured.

1A is a schematic cross sectional view of a roller hearth kiln.

FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

2 shows a schematic diagram in a batch.

3 is a temperature profile diagram of a calcination process of Example 1;

4 is a temperature profile diagram of the firing process of Examples 2 and 3. FIG.

5 is a temperature profile diagram of a calcination process of Example 4. FIG.

6 is a temperature profile diagram of a calcination process of Example 5. FIG.

7 is a graph showing the relationship between the specific resistance of a thin film formed by sputtering using the target materials obtained in Example 6 and Comparative Example 8 and the oxygen partial pressure at the sputtering time.

Explanation of the sign

1: roller hearth kiln, 3, 21: fired body, 5, 5 ': gas inlet / outlet,

7, 7 ': roller, 9, 9', 17: heater, 11: partition, 15: batch,

2, 19: fired plate

[Best Mode for Carrying Out the Invention]

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

The manufacturing method of the target material of this invention is a method of manufacturing the target material of a sputtering target by the powder metallurgy method, Comprising: Producing a target material through a specific cooling process in addition to a specific heating process, More preferably, the heating process. It features.

That is, in the powder metallurgy method, in general, a raw material powder is added by compression to a binder as desired, the obtained molded body is degreased as needed, and then the molded body (hereinafter referred to as a to-be-baked body) is fired to obtain a sintered body. In this invention, it has a specific heating process at the time of this baking process, It is characterized by having a specific cooling process in addition to the heating process.

Specifically, the process from adding a binder to the raw material powder as desired to compression molding to obtain a molded article and degreasing the obtained molded article as necessary can be performed by known means and conditions that are usually performed.

The raw material powder may be calcined and classified as necessary, and the subsequent mixing of the raw material powder can be performed by, for example, a ball mill.

Thereafter, the mixed raw material powder is filled into a molding die and compression molded to produce a molded body, and degreased under an atmospheric or oxygen atmosphere to obtain a to-be-fired body, or as described in JP-A-11-286002. Like the over-molding method, a slurry made of mixed raw material powder, ion-exchanged water, and an organic additive is injected into a filter forming mold made of a non-aqueous material for obtaining a molded body by depressurizing and draining water from the ceramic raw material slurry, and the water in the slurry The molded object may be produced by depressurizingly draining the molded product, and the molded product may be dried and degreased to obtain a fired body.

Degreasing | molding of a molded object is performed as needed, and when it is not degreased, the molded object turns into a to-be-baked body as it is. In addition, degreasing can also be performed in the continuous furnace mentioned later.

This invention has the heating process which sinters a to-be-baked material from one side with respect to each to-be-baked material obtained in this way.

As the heating step, a step of heating the to-be-baked body so that both ends of the to-be-baked body have a temperature difference with respect to each of the to-be-baked materials, more specifically,

For each of the to-be-baked bodies, a step of heating the to-be-baked bodies simultaneously over two or more adjacent regions set at different temperatures is preferable.

In addition, the firing process can be performed continuously, and in view of high production efficiency, the heating step is carried out while conveying the object to be processed so as to cover two or more adjacent areas set at different temperatures at the same time. More preferably.

As described above, when the object is heated while being transported so as to cover the two or more regions at the same time in the heating step, the object is heated sequentially from the end of the conveying direction and sintered per one of the objects to be baked. I can let you go. For this reason, also when manufacturing a so-called long object and a large target material, since sintering takes place sequentially from the end of the conveyance direction side of a to-be-baked body, and shrinkage | contraction by the sintering of the to-be-processed body advances sequentially, therefore, of the target material finally obtained The density can be improved, and the density nonuniformity can be improved, and the occurrence of warpage and cracking can also be prevented.

Therefore, this invention is especially the target material of the long object which a to-be-baked body covers three or more area | regions in the said heating process (for example, the target material of length 500-1000 mm, width 10-500 mm, thickness 3-30 mm in the dimension after baking). It can apply suitably for manufacture of the. In other words, the number of regions in the heating step is not particularly limited as long as it is two or more, but three or more are preferable. Although the upper limit of the number of the area | regions to which a to-be-baked body spreads can be set suitably according to the dimension of the target material to obtain, normally 5 or less can respond to the target material of various dimensions, and is convenient.

In addition, the length (length in the longitudinal direction) of the conveyance direction side of each area | region in the said heating process may be the same as the other area | region, and may differ from each area | region, suitably according to the magnitude | size of a to-be-baked body, the size of the furnace to be used, the number of the area | regions installed, etc. Although it can determine, 300-490 mm is preferable normally.

In contrast, when an attempt is made to produce a so-called long object or a large target material by a manufacturing method that does not have such a heating process, for example, when the long object or a large to-be-fired body is fired in a batch furnace under conventional firing conditions, Since the shrinkage due to the sintering and sintering of the body to be processed proceeds from the surface of the entire body to the center, since the body is long or large, the shrinkage due to the sintering of the body to be processed has its own weight. ), The density of the target material finally obtained is difficult to improve, and problems such as density unevenness, warpage, and cracking appear.

Moreover, in this invention, the temperature of each area | region of the said 2 or more area | region in the said heating process is 10-500 degreeC normally, Preferably it is 50-400 degreeC, More preferably, compared with the temperature of the area | region adjacent to each other among these. Preferably, the conveyance speed of the to-be-baked material which passes through these two or more areas | regions is set so that it may become high sequentially, respectively, toward a conveyance direction within the range of 100-350 degreeC, normally 1-50 mm / min. to be.

Moreover, in this invention, it is preferable that the temperature of the region with the lowest temperature among the said 2 or more areas exists normally in the range of room temperature-800 degreeC.

Here, a description will be given of the relationship between the set temperature of each region in the heating step, the temperature difference between the adjacent regions, and the conveyance speed, taking three cases as an example, for example, in order of a, b, c. In the three regions a to c which exist adjacent to each other in the conveying direction, each of the regions a, b, and c are set to different temperatures, and the setting temperature is preferably a <b <c. , The temperature difference (= ba) between the region a and the region b, and the temperature difference (= cb) between the region b and the region c are each within the above temperature range.

And the to-be-baked body conveys at least 2 or more adjacent area | regions among these areas a-c at the same time, Preferably it conveys between at least 2 or more area | regions adjacent to the said area a-c at the conveyance speed within the said range. Is heated.

As described above, in the heating step, the temperatures of two or more regions adjacent to each other are set so as to be sequentially increased as the conveying direction of the to-be-baked body is at a temperature within the above range, and the conveying speed of the to-be-baked body passing through these areas is further increased. When the speed is within the above range, the body to be heated is heated from one end of the body, in other words, on the conveyance direction side of the body to pass through these regions. Thereby, sintering advances from one end of the to-be-fired body, in other words, on the conveying direction side of the to-be-fired body, but even in this case, shrinkage due to sintering of the to-be-fired body proceeds more smoothly, so that cracking and warping do not occur. Do. In addition, when the aspect ratio of the widest surface of a to-be-baked body differs in aspect ratios, such as a rectangle, what is necessary is just to mount and convey a to-be-baked body so that the long side of the surface may become parallel to a conveyance direction.

Moreover, if it is conditions of such temperature conditions and a conveyance speed, the increase of the production amount per unit time is anticipated, and it is preferable also from a production efficiency viewpoint.

Moreover, the temperature detection apparatuses, such as a thermocouple, provided in the substantially intermediate point with respect to the length (length in the longitudinal direction of each area | region) of the conveyance direction side of each area | region for each area | region in the said heating process, and the setting temperature of each area | region of two or more area | regions. Determined by At this time, the temperature between the respective temperature detection devices provided in the areas adjacent to each other is usually adjusted to increase at a rate of 0.02 to 1.11 ° C / mm, preferably 0.11 to 0.99 ° C / mm, more preferably 0.22 to 0.78 ° C / mm. It is preferable that it is done.

Moreover, it is preferable that the manufacturing method of the target material of this invention has a cooling process which cools the to-be-baked material so that both ends may have a temperature difference with respect to each to-be-baked material after a heating process in addition to the said heating process.

Specifically, it is preferable that the cooling step is a step of cooling while simultaneously covering two or more adjacent areas set to different temperatures with respect to one object to be baked after the heating step,

It is more preferable that it is a process of cooling, conveying the to-be-baked material so that it may spread over two or more adjacent areas | regions set to different temperature simultaneously with respect to each to-be-baked material after a heating process.

Through such a cooling process, the to-be-baked body after a heating process, ie, a sintered compact, can be cooled sequentially from the end of the conveying direction side to one of the sintered compacts.

In the cooling step, the temperature of each region of the two or more regions is usually 10 to 500 ° C, preferably 50 to 400 ° C, more preferably 100 to 350 ° C, compared with the temperature of the regions adjacent to each other among them. The conveyance speed of each of the to-be-baked bodies passing through these two or more regions is set in a range of 1 to 50 mm / min, respectively, so as to be sequentially lowered in the conveyance direction within the range of.

Moreover, in this invention, in the said cooling process, it is preferable that the temperature of the area with the highest temperature among the said 2 or more areas exists normally in the range of 1300-1800 degreeC.

Here, in the cooling process, when the relationship between the set temperature of each area | region, the temperature difference of each area | region adjacent, and a conveyance speed is demonstrated taking the case of three area | region as an example, it will be a to-be-baked body in order of d, e, f, for example. In the three regions d to f which are adjacent to each other, the respective regions d, e, and f are set to different temperatures, and the set temperature is preferably d> e> f. , The temperature difference (= de) between the region d and the region e is equal to the temperature difference (= ef) between the region e and the region f, respectively.

And the to-be-baked body conveys at least 2 or more adjacent area | regions among these areas d-f simultaneously, Preferably it carries between at least 2 or more adjacent area | regions among the area | regions d-f at the conveyance speed within the said range. As it cools down.

As described above, in the cooling step, the temperatures of two or more regions adjacent to each other are set to be sequentially lowered in the above range toward the conveying direction of the to-be-baked body, and the conveying speed of the to-be-baked body passing through these areas is If it is set in the said range, when a to-be-baked body passes through these area | regions, it will cool from one end of a to-be-baked body, in other words, the conveyance direction side of a to-be-baked material, but also a crack, a bending, etc. do not generate | occur | produce in this case. Moreover, if it is conditions of such temperature conditions and a conveyance speed, the increase of the production amount per unit time is anticipated, and it is preferable also from a production efficiency viewpoint.

Therefore, this invention is especially the target material of the long object which a to-be-baked body covers three or more area | regions in the said cooling process (for example, the target material of length 500-1000 mm, width 10-500 mm, thickness 3-30 mm in the dimension after baking). It can apply suitably for manufacture of the. In other words, the number of regions in the cooling step is not particularly limited as long as it is two or more, but three or more are preferable. Although the upper limit of the number of the area | regions to which a to-be-baked body spreads can be set suitably according to the dimension of the target material to obtain, normally 5 or less can respond to the target material of various dimensions, and is convenient.

The length (length in the longitudinal direction) of the conveyance direction side of each region in the cooling step may be the same as or different from other regions for each region, and can be appropriately determined according to the size of the body to be baked, the size of the furnace used, the number of regions to be arranged, and the like. However, 300-490 mm is preferable normally.

In addition, in the said cooling process, the set temperature of each area | region of two or more area | regions is a temperature detection apparatus, such as a thermocouple provided in the substantially intermediate point with respect to the length (length in the longitudinal direction of each area | region) of the conveyance direction side of each area | region for every area | region. Determined by At this time, the temperature between the respective temperature detection devices provided in the areas adjacent to each other is usually set to fall at a rate of 0.02 to 1.11 ° C / mm, preferably 0.11 to 0.99 ° C / mm, more preferably 0.22 to 0.78 ° C / mm. It is preferable that it is done.

Moreover, in the manufacturing method of the target material of this invention, when a heating process is performed in multiple times in steps between the said heating process and a cooling process as needed, a heat retention process can also be provided between each heating process. In the thermal insulation process, the temperature of the heating process region immediately nearby is maintained. The length, the number, and the like of the region in the thermal insulation step can be appropriately determined according to the size of the to-be-baked body, the size of the furnace to be used, the total number of regions to be arranged, and the like.

In addition, the target material which can be manufactured by the manufacturing method of the target material of this invention should just be what can be manufactured by the powder metallurgy method, and is not specifically limited. Examples of the target material include oxides (ITO; In ₂ O ₃ -SnO ₂ ), In ₂ O ₃ -ZnO, SnO ₂ -Sb ₂ O ₃ , and ZnO-Al _{2 which have} indium oxide and tin oxide as main components. Ceramic sintered target materials such as O ₃ ; Metal target materials, such as W type | system | group, Mo type | system | group, Al type, and Ti type, are mentioned. In these, the ceramic sintered compact target material is preferable at the point which can exhibit the effect of this invention more effectively, and an ITO target material is more preferable especially.

In addition, the specification of, ITO target is, to the tin oxide of 1-35% by weight of (SnO ₂₎ to indium oxide typically (In ₂ O ₃₎ was added; means a material obtained.

In the manufacturing method of the target material of this invention, it is preferable to perform the said heating process in a continuous furnace, and it is more preferable to perform the said heating process and a cooling process in a continuous furnace. Here, a continuous furnace means the furnace which can continuously heat a to-be-baked body, or the furnace which can heat and cool a to-be-baked material continuously, Specifically, for example, a roller has kiln, a pusher furnace And mesh belt furnaces.

In addition, from the viewpoint of reducing the inclination of the temperature distribution in the width direction in the furnace and achieving uniform heating in the width direction portion of the to-be-baked body, the continuous path is heated in the vertical direction, bounded by the conveying path of the to-be-baked material. It is preferable to have, and it is more preferable that it is a roller hearth kiln. In addition, when a heating means is provided in the up-down direction on the basis of the conveyance path of the to-be-baked body, a thermocouple may also be provided up and down similarly, and temperature detection and temperature control may be performed up and down.

Moreover, in implementing the manufacturing method of this invention, air | atmosphere, oxygen, nitrogen, hydrogen, etc. can be introduce | transduced into the continuous furnace.

Specifically, when the ceramic sintered compact target material is produced by the production method of the present invention, it is preferable to introduce oxygen into the continuous furnace to perform the heating step and / or the cooling step in an oxygen atmosphere. It is preferable from a viewpoint of improvement. The flow rate of oxygen introduced into the continuous furnace is usually an amount within the range of 0.1 to 500 m ³ / h.

Moreover, when manufacturing a metal target material by the manufacturing method of this invention, introducing a reducing atmosphere, such as hydrogen, into the said continuous furnace, and performing the said heating process and / or cooling process in a reducing atmosphere is oxidation of a metal. It is preferable from a viewpoint of preventing.

EMBODIMENT OF THE INVENTION Hereinafter, the case where the manufacturing method of the target material of this invention is performed by a roller hearth kiln is taken as an example, and it demonstrates, referring drawings as needed.

A roller hearth kiln is a kind of continuous furnace which can provide a preheating zone, a heating zone, a heat insulation zone, a cooling zone, etc. according to the set temperature, and can implement a specific temperature profile.

1A is a schematic cross-sectional view of an example of a roller hearth kiln that can be used in the present invention. In FIG. 1A, the to-be-baked body 3 baked in the roller hearth kiln 1 is preheated, heated, while conveyed in the arrow direction by the some roller rotation from the roller 7 to the roller 7 '. It heats, cools, etc., and bakes. The to-be-baked body 3 may be mounted in the baking plate 2 as shown. In addition, although the example shown is one-stage embodiment in which the to-be-baked body 3 was mounted to the baking board 2, you may carry out by two steps | times stacking | stacking, three steps | steps stacking | stacking etc. in more stages.

FIG. 1B is a cross-sectional view taken along line II ′ of the roller hearth kiln shown in FIG. 1A, and the upper and lower sides of the roller 3 to be transported by the roller 7 are transported by the roller 7. Heaters 9 and 9 'are provided. The temperature in the furnace is adjusted to the set temperature by these heaters 9 and 9 '.

In FIG. 1A, the fired body 3 is partitioned by the partition 11, and two or more adjacent regions (hereinafter, referred to as regions) set to different temperatures by the heater 9, the heater 9 ', and the like. It may simply be referred to as "zone", and is heated or cooled while being conveyed so as to span at the same time by the rotation of the plurality of rollers 7 (for example, in FIG. 1A, conveyed to cover four areas at the same time). Being).

At this time, Preferably, gas, such as oxygen, can be introduce | transduced and discharge | emitted from gas introduction and discharge ports (5 and 5 '), and baking can be performed in gas atmosphere.

Moreover, as far as the present inventors know, the example which calcined ITO raw material powder in the roller hearth kiln is reported, but the example which calcined and manufactured the ITO target material is not reported.

Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

Example 1

Using a roller Haas kiln (16 zones, 7200 mm in total length), 10% by weight of SnO _{2 is} added to In ₂ O ₃ (SnO ₂ , 665 mm x) while flowing oxygen gas with an oxygen concentration of 100% in the furnace. 235 mm x 15 mm, 11.4 kg; hereinafter referred to simply as a degreasing body) was fired under the conditions shown in Tables 1 and 2 (the temperature profile is shown in Fig. 3) in a state of mounting on a firing plate (800 mm x 300 mm x 25 mm). ), ITO target material was obtained. The actual firing time at this time was 48 hours same as the set firing time.

About the obtained ITO target material, baking density (g / cm <^3> ) and curvature (mm) were calculated | required by the following method, and the presence or absence of a crack was evaluated visually.

The firing density was calculated by cutting the obtained ITO target material into a substantially rectangular parallelepiped, figuring the surface, measuring the weight, and dividing the weight by the volume of the rectangular parallelepiped after the surface finishing. In addition, the volume of the rectangular parallelepiped after surface-treatment processing uses Nogisu (Mitsutoyo Co., Ltd., the M type standard Nogis N100 (JIS B 7507)), and a micrometer (Mitsutoyo Co., Ltd., count outer micrometer M820-25 (JIS B 7502)). It calculated from the measured value obtained by.

The curvature placed the obtained ITO target material on the flat plate, and measured the maximum value of the space between a flat plate and an ITO target material using a gap gauge (made by Nagai gauge Seisakusho, JIS schema gauge JIS B 7524-1992).

In addition, the theoretical plastic weight at the time of manufacturing over 10 days was calculated | required by the following formula.

10-day theoretical plastic weight (kg)

[The number of firings per unit time (sheet / time)] * 240 (time) X degreasing body weight (kg / sheet)

As a result, it was [(7200/800) / 48] x 240 x 11.4 = 513 kg.

In addition, the number of firings per unit time (sheets / hour) is based on the number of firing bodies (sheets) (that is, furnace full length (mm) / baking plate length (mm)) / actual firing time (hours) in the furnace ''. Saved.

These results are summarized in Table 1.

[Examples 2 and 3]

The ITO target material was obtained by the same method as Example 1 except having changed baking conditions into the conditions shown in Table 1 and Table 3 (temperature profile is shown in FIG. 4. Temperature profile is common to Examples 2 and 3.). In Example 2 and 3, the actual baking time was 16 hours same as the preset baking time.

About the obtained ITO target material, baking density and curvature were calculated | required similarly to Example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was obtained.

The theoretical firing weight for 10 days was [(7200/800) / 16] x 240 x 11.4 = 1539 kg in Examples 2 and 3.

These results are summarized in Table 1.

[Examples 4 and 5]

Using a roller Haas kiln (24 zones, 10800 mm in total length), 10% by weight of SnO ₂ added to In ₂ O ₃ was added while degassing oxygen gas with an oxygen concentration of 100% in the furnace. Firing under the conditions shown in Table 1 and Table 4 (Example 4) or Table 1 and Table 5 (Example 5), respectively, with 235 mm x 15 mm and 11.4 kg mounted on a firing plate (800 mm x 300 mm x 25 mm) (The temperature profile of Example 4 is shown in FIG. 5, and the temperature profile of Example 5 is shown in FIG. 6), and the ITO target material was obtained. In Examples 4 and 5, the actual firing time was 21.4 hours which was the same as the set firing time.

About the obtained ITO target material, baking density and curvature were calculated | required similarly to Example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was determined.

In Examples 4 and 5, the theoretical firing weight for 10 days was [(10800/800) /21.4] x 240 x 11.4 = 1721 kg.

These results are summarized in Table 1.

Example 6

The ITO target material obtained in Example 4 was cut out and bonded with the copper backing plate, and the ITO sputtering target of 6 inches of diameter x thickness 4mm was produced.

By using this ITO sputtering target, the oxygen partial pressure in the sputtering apparatus is changed under the following conditions, sputtering is performed, and the specific resistance of the formed ITO thin film is measured, and the oxygen partial pressure dependency upon sputtering of the ITO target material to the specific resistance of the ITO thin film is determined. Investigated.

The results are shown in Table 6 and FIG.

<Sputtering condition>

Device; High rate sputter device (HSD 50L remodeling, product made by Syncron Corporation)

Deposition conditions:

Reach vacuum degree; 6 × 10 ⁻⁴ Pa, substrate temperature; Room temperature,

Process pressure; 0.5 Pa (Ar 50 sccm), oxygen introduction amount; 0-2sccm

Target-to-board distance: 70 mm

Board; Corning # 1737

Film thickness; 300nm band

In addition, sccm is standard cc / min, and means the gas flow volume converted on the conditions of 0 degreeC and 1 atm.

Comparative Example 1

Using a batch furnace, 10% by weight of SnO _{2 was} added to In ₂ O ₃ , 665 mm x 235 mm, while degassing 100% oxygen gas in the furnace (flow rate 1.0 m ³ / h). 15 mm and 11.4 kg (hereinafter also referred to simply as a degreasing body) were fired in a firing pattern shown below in a state where a firing plate (800 mm × 300 mm × 25 mm) was mounted, thereby obtaining an ITO target material. The set firing time at this time was 48 hours, and the actual firing time was 72 hours.

Firing conditions;

Room temperature → (30 ℃ / hr) → 400 ℃ → (50 ℃ / hr) → 800 ℃ × 3hr → (100 ℃ / hr) → 1400 ℃ × 6hr → (-100 ℃ / hr) → 500 ℃ → furnace cooling

About the obtained ITO target material, baking density and curvature were calculated | required similarly to Example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical plastic weight of 10 days was calculated | required by the following formula.

10-day theoretical plastic weight (kg)

[The number of firings per sheet (sheets) × 240 (hours) / baking time (hours)] × degreasing body weight (kg / sheet)

Since 12 sheets of degreasing bodies can be thrown in to the used batch furnace, 12 sheets of baking sheets per batch were made into 12 sheets, and it became [12 * 240/72] * 11.4 = 456 kg.

These results are summarized in Table 1.

Comparative Example 2

The ITO target material was obtained by the method similar to the comparative example 1 except having baked with the baking pattern shown below. The set firing time at this time was 16 hours, and the actual firing time was 36.5 hours.

Firing conditions;

Room temperature → (320 ℃ / hr) → 800 ℃ × 1hr → (300 ℃ / hr) → 1400 ℃ × 4hr → (-250 ℃ / hr) → 650 ℃ → furnace cooling

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, about the theoretical baking weight for 10 days, since all obtained ITO target materials were split, it was set to 0.

These results are summarized in Table 1.

Comparative Example 3

An ITO target material was obtained in the same manner as in Comparative Example 2, except that oxygen gas was not flowed into the furnace but air was flowed (flow rate 1.0 m ³ / h). The set firing time at this time was 16 hours, and the actual firing time was 36.5 hours.

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, about the theoretical baking weight for 10 days, since all obtained ITO target materials were split, it was set to 0.

These results are summarized in Table 1.

[Comparative Example 4]

The ITO target material was obtained by the method similar to the comparative example 1 except having baked with the baking pattern shown below. The set firing time at this time was 54.3 hours, and the actual firing time was 78.3 hours.

Firing conditions;

Room temperature → (30 ℃ / hr) → 400 ℃ → (50 ℃ / hr) → 800 ℃ × 1hr → (300 ℃ / hr) → 1400 ℃ × 4hr → (-50 ℃ / hr) → 800 ℃ → furnace cooling

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was [12 × 240 / 78.3] × 11.4 = 419 kg.

These results are summarized in Table 1.

[Comparative Example 5]

An ITO target material was obtained in the same manner as in Comparative Example 4, except that oxygen gas was not flowed into the furnace but air was flowed (flow rate 1.0 m ³ / h). The set firing time at this time was 54.3 hours, and the actual firing time was 78.3 hours.

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was [12 × 240 / 78.3] × 11.4 = 419 kg.

These results are summarized in Table 1.

Comparative Example 6

The ITO target material was obtained by the method similar to the comparative example 1 except having baked with the baking pattern shown below. The set firing time at this time was 62.9 hours, and the actual firing time was 84 hours.

Firing conditions;

Room temperature → (30 ℃ / hr) → 400 ℃ → (50 ℃ / hr) → 800 ℃ × 0.9hr → (300 ℃ / hr) → 1600 ℃ × 8hr → (-50 ℃ / hr) → 800 ℃ → furnace cooling

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was [12 × 240/84] × 11.4 = 391 kg.

These results are summarized in Table 1.

Comparative Example 7

Except having baked with the baking pattern shown below, the ITO target material was obtained by the method similar to the comparative example 1. The set firing time at this time was 63.9 hours, and the actual firing time was 85 hours.

Room temperature → (30 ℃ / hr) → 400 ℃ → (50 ℃ / hr) → 800 ℃ × 0.9hr → (318 ℃ / hr) → 1650 ℃ × 8hr → (-50 ℃ / hr) → 800 ℃ → furnace cooling

About the obtained ITO target material, baking density and curvature were calculated | required similarly to the comparative example 1, and the presence or absence of the crack was evaluated. In addition, the theoretical firing weight for 10 days was [12 × 240/85] × 11.4 = 386 kg.

These results are summarized in Table 1.

Comparative Example 8

Except for using the ITO target material obtained in Comparative Example 6 in the same manner as in Example 6 to produce an ITO sputtering target, sputtering, measuring the specific resistance of the formed ITO thin film, the sputtering of the ITO target material to the specific resistance of the ITO thin film The oxygen partial pressure dependence of was investigated.

The results are shown in Table 6 and FIG.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

From Table 6 and FIG. 7, for example, in order to form an ITO thin film having a specific resistance of 5.0 × 10 ⁻⁴ Ω · cm or less, when using an ITO target material manufactured using a batch furnace, the amount of oxygen introduced during sputtering is determined. Although it is necessary to control to about 0.3-0.8 sccm, when using the ITO target material manufactured using the continuous furnace, it turns out that there is no problem even if the amount of introduced oxygen at the time of sputtering spreads to about 0.3-1.1 sccm. .

That is, compared with the ITO target material manufactured using the batch furnace, the ITO target material manufactured using the continuous furnace has a small dependence on the oxygen partial pressure at the time of sputtering to the specific resistance of the thin film formed by sputtering, and sintered from one side of the body It turns out that a thin continuous furnace is more suitable for manufacture of the target material for sputtering targets than a batch furnace.

According to this invention, the target material for sputtering targets, especially what is called a long object and a large target material, can also be manufactured in a short time with high quality and high production efficiency. Therefore, the present invention is useful in the manufacture of sputtering targets.

Claims (21)

As a method of manufacturing the target material of a sputtering target by the powder metallurgy method, A manufacturing method of the target material characterized by having the heating process which heats the to-be-baked material so that the both ends may have a temperature difference with respect to each to-be-baked material, and sinters the to-be-baked material from the one side. The method of claim 1, The said heating process is a process of heating a to-be-baked material over 2 or more adjacent areas | regions set to different temperature with respect to each to-be-baked material simultaneously, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 2, The said heating process WHEREIN: The manufacturing method of the target material of the two or more area | regions in which the set temperature of the area with the lowest temperature exists in the range of room temperature-800 degreeC. The method of claim 1, The said heating process is a process of heating, conveying the to-be-baked material so that it may cover the two or more adjacent areas set to different temperature simultaneously with respect to each to-be-baked material, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 4, wherein In the said heating process, the temperature of each area | region of the said 2 or more area | regions is respectively set so that it may become sequentially high as it goes to a conveyance direction within the range of 10-500 degreeC compared with the temperature of the area | region adjacent to each other among these, Moreover, the conveyance speed of the to-be-baked material which passes through these two or more area | regions is the range of 1-50 mm / min, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 5, The said heating process WHEREIN: The manufacturing method of the target material of the two or more area | regions in which the set temperature of the area with the lowest temperature exists in the range of room temperature-800 degreeC. The method of claim 1, The said heating process is performed in a continuous furnace, The manufacturing method of the target material characterized by the above-mentioned. The method according to any one of claims 1 to 7, In addition to the said heating process, it has a cooling process of cooling the to-be-baked material so that the both ends may have a temperature difference with respect to each to-be-baked material after a heating process, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 8, The said cooling process is a process of cooling, while permeating a to-be-baked material to two or more areas set to different temperatures simultaneously with respect to each to-be-baked material after a heating process, The target material manufacturing method of the target material characterized by the above-mentioned. The method of claim 9, The said manufacturing process WHEREIN: The manufacturing method of the target material characterized by the set temperature of the area with the highest temperature among the said 2 or more area | regions in the range of 1300-1800 degreeC. The method of claim 8, The said cooling process is a process of cooling, conveying the to-be-baked material so that it may cross over two or more adjacent areas set to different temperatures simultaneously with respect to each to-be-baked material after a heating process, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 11, In the cooling step, the temperatures of the respective regions of the two or more regions are set so as to be sequentially lowered toward the conveyance direction within the range of 10 to 500 ° C, compared with the temperatures of the regions adjacent to each other among them, Moreover, the conveyance speed of the to-be-baked material which passes through these two or more area | regions is the range of 1-50 mm / min, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 12, The said manufacturing process WHEREIN: The manufacturing method of the target material characterized by the set temperature of the area with the highest temperature among the said 2 or more area | regions in the range of 1300-1800 degreeC. The method of claim 8, A method for producing a target material, characterized in that the cooling step is performed in a continuous furnace. The method according to claim 7 or 14, The continuous furnace is provided with heating means above and below the conveyance path of a to-be-baked body, The manufacturing method of the target material characterized by the above-mentioned. The method according to claim 7 or 14, The continuous furnace is a roller hearth kiln (roller hearth kiln), characterized in that the manufacturing method of the target material. The method according to claim 7 or 14, Oxygen is introduced into the said continuous furnace, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 17, A flow rate of oxygen introduced into the continuous furnace is an amount within a range of 0.1 to 500 m ³ / h. The method of claim 1, The said target material is a target material for transparent conductive film formation, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 1, The said target material is an oxide which has at least 1 of indium oxide, tin oxide, and zinc oxide as a main component, The manufacturing method of the target material characterized by the above-mentioned. The method of claim 1, The said target material is an oxide (ITO) which has indium oxide and tin oxide as a main component, The manufacturing method of the target material characterized by the above-mentioned.

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