CN111748779B

CN111748779B - Divided sputtering target and method for producing same

Info

Publication number: CN111748779B
Application number: CN201911394975.6A
Authority: CN
Inventors: 梶山纯
Original assignee: JX Nippon Mining and Metals Corp
Current assignee: JX Nippon Mining and Metals Corp
Priority date: 2019-03-27
Filing date: 2019-12-30
Publication date: 2022-10-14
Anticipated expiration: 2039-12-30
Also published as: TW202035748A; JP2020158854A; CN111748779A; KR20200115039A; JP7311290B2; TWI741477B; KR102302468B1

Abstract

The present invention provides a divided sputtering target formed by bonding a plurality of sputtering target members to a backing plate, wherein the thickness of each sputtering target member is controlled. A divided sputtering target is provided with: a plurality of flat sputtering target members arranged on the backing plate with a gap therebetween; a bonding material disposed between the backing plate and each sputtering target member; a shielding material disposed in the gap between adjacent sputtering target members; and a plurality of linear spacers arranged between the backing plate and each sputtering target member at positions not overlapping the shielding material, for adjusting the thickness of the bonding material.

Description

Divided sputtering target and method for producing same

Technical Field

The present invention relates to a divided sputtering target in which a plurality of sputtering target members, particularly a plurality of oxide semiconductor sputtering target members, are joined to a backing plate. The present invention also relates to a method for manufacturing a divided sputtering target.

Background

Sputtering is often used as a film formation method for producing thin films of various electronic devices including display devices such as liquid crystal displays and organic EL displays. In recent years, as display devices have been increased in size, sputtering targets used in sputtering methods have been required to be increased in size.

As a sputtering target for a display device, an oxide semiconductor sputtering target member is often used. However, since the oxide semiconductor sputtering target member is made of ceramic, it is brittle and thus it is difficult to increase the area. Therefore, conventionally, a divided sputtering target in which a plurality of sputtering target members are joined to a backing plate has been used.

In the case of using the divided sputtering target, in consideration of a difference in thermal expansion between the material (typically, copper) constituting the backing plate and the sputtering target member, a slight gap is usually provided between the adjacent sputtering target members. However, if there is a gap between adjacent sputtering target members, the backing plate is also sputtered at the time of sputtering, and the material (typically copper) constituting the backing plate is mixed into the sputtered film, which may adversely affect the characteristics of the sputtered film. Therefore, a method has been proposed in which a shielding material is disposed in a gap between adjacent sputtering target members in a divided sputtering target to prevent the backing plate from being exposed.

Japanese patent No. 5711172 (patent document 1) proposes a divided sputtering target formed by joining a plurality of target members to a backing plate with a low-melting-point solder, wherein a protective member is provided on the backing plate along a gap formed between the joined target members, the target members are oxide semiconductors, the protective member is composed of a band-shaped 1 st protective member and a band-shaped 2 nd protective member, the 2 nd protective member is disposed on the backing plate side, the 1 st protective member is laminated on the 2 nd protective member, and the 1 st protective member is a polymer sheet.

Japanese patent No. 6079228 (patent document 2) proposes a multi-segment sputtering target in which a wire-like protective material made of metal is provided on a solder material along the bottom of segments formed on adjacent target materials so that the solder material does not expose, and the height of the protective material is 1/10 or less of the height from the back plate surface to the target material surface.

Japanese patent No. 4961513 (patent document 3) proposes a divided sputtering target formed by bonding a plurality of target members to a backing plate by low-melting-point solder, wherein a gap formed between the bonded target members is filled with a ceramic material composed of ceramic powder containing a metal element constituting the target member, and the filling thickness of the ceramic powder is 10% to 70% of the depth of the gap formed between the target members.

Japanese patent No. 4961514 (patent document 4) proposes a divided sputtering target in which a plurality of target members are joined to a backing plate by low-melting-point solder, characterized in that a protective body is provided on the backing plate along a gap formed between the joined target members, the protective body is composed of a strip-shaped 1 st protective member and a strip-shaped 2 nd protective member, the 2 nd protective member is disposed on the backing plate side, the 1 st protective member is laminated on the 2 nd protective member, the 1 st protective member is composed of a ceramic material composed of an oxide or a nitride.

Documents of the prior art

Patent literature

Patent document 1: japanese patent No. 5711172

Patent document 2: japanese patent No. 6079228

Patent document 3: japanese patent No. 4961513

Patent document 4: japanese patent No. 4961514

Disclosure of Invention

Technical problem to be solved by the invention

As described above, in the divided sputtering target, a method of preventing the back plate from being exposed by disposing a shielding material in the gap between the adjacent sputtering target members has been proposed. However, in the case of dividing the sputtering target, since each sputtering target member is independently bonded to the backing plate, there is a problem that unevenness is likely to occur in the thickness of the bonding material such as low melting point solder. In the related art, studies for controlling the thickness of a bonding material for bonding each divided sputtering target member are still insufficient.

The present invention has been made in view of the above circumstances, and an object of one embodiment is to provide a divided sputtering target in which a plurality of sputtering target members are joined to a backing plate, the divided sputtering target being formed by controlling the thickness of each sputtering target member. In another embodiment, the present invention is directed to a method for manufacturing such a divided sputtering target.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above-described problems, and found that it is advantageous to dispose a linear spacer between the backing plate and each sputtering target member. Further, it was found that the spacer is disposed so as not to overlap with the shielding material provided in the gap between the adjacent sputtering target members, and is advantageous in thickness control. The present invention has been completed based on the above knowledge, and is exemplified hereinafter.

[1]

A divided sputtering target is provided with: a plurality of flat sputtering target members arranged on the backing plate with a gap therebetween; a bonding material disposed between the backing plate and each sputtering target member; a shielding material disposed in the gap between adjacent sputtering target members; and a plurality of linear spacers arranged between the backing plate and each sputtering target member at positions not overlapping the shielding material, for adjusting the thickness of the bonding material.

[2]

The split sputtering target according to [1], wherein in a plan view, none of the plurality of linear spacers has a portion extending from an outer peripheral side surface of the sputtering target member.

[3]

The divided sputtering target according to [1] or [2], wherein one end or both ends of at least one of the plurality of linear spacer members are positioned directly below a portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed.

[4]

The divided sputtering target according to item [3], wherein at least one of the plurality of planar sputtering target members is rectangular in plan view, and at least one of the plurality of linear spacers has both ends thereof positioned directly below an outer peripheral side surface of one of the four sides constituting the at least one sputtering target member rectangular in plan view, or each end thereof positioned directly below each outer peripheral side surface constituting two adjacent sides.

[5]

The divided sputtering target according to [4], wherein at least one of the plurality of linear spacers has both ends positioned directly below an outer peripheral side surface of one of four sides constituting the at least one sputtering target member having a rectangular shape in plan view, and is disposed between the backing plate and the at least one sputtering target member having a rectangular shape in plan view in a V-shape in plan view in which a tip end becomes narrower as it goes away from the both ends.

[6]

The divided sputtering target according to item [4], wherein at least one of the plurality of linear spacer members has both ends positioned directly below an outer peripheral side surface of one of four sides constituting the at least one sputtering target member having a rectangular shape in plan view, and is disposed between the backing plate and the at least one sputtering target member having a rectangular shape in plan view in an equilateral trapezoid shape whose tip becomes narrower as it goes away from the both ends.

[7]

The divided sputtering target according to [4], wherein at least one of the plurality of linear spacers has each end positioned directly below each of outer peripheral side surfaces of two adjacent sides among the four sides constituting the at least one rectangular sputtering target member viewed in a plan view, and is arranged in an L-shape in a plan view between the backing plate and the at least one rectangular sputtering target member viewed in a plan view.

[8]

The divided sputtering target according to any one of [1] to [7], wherein the plurality of flat plate-like sputtering target members are formed of an oxide semiconductor.

[9]

The divided sputtering target according to any one of [1] to [8], wherein the plurality of linear spacers have a diameter of 0.1mm to 1.0mm.

[10]

The split sputtering target according to any one of [1] to [9], wherein the material of the plurality of linear spacers is a metal selected from the group consisting of copper, titanium, iron, aluminum, nickel, and chromium, or an alloy containing one or more of the metals.

[11]

The divided sputtering target according to any one of [1] to [10], wherein the upper surface of the shielding material is located below the lower surface of each sputtering target member, and the bonding material is interposed between the upper surface of the shielding material and the lower surface of each sputtering target member.

[12]

The divided sputtering target according to [11], wherein the length of the plurality of linear spacers in the thickness direction of the shielding material is larger than the thickness of the shielding material.

[13]

The divided sputtering target according to [11] or [12], wherein the width of the shielding material disposed in the gap is the same as or larger than the interval between the sputtering target members adjacent to each other.

[14]

The divided sputtering target according to any one of [1] to [13], wherein the plurality of plate-like sputtering target members are each rectangular in plan view and are arranged in 2 rows × N columns (N is a natural number of 1 or more) on the backing plate.

[15]

The divided sputtering target according to any one of [1] to [14], wherein a material of the shielding material has an insulating property.

[16]

The divided sputtering target according to any one of [1] to [15], wherein the shielding material is exposed in the gap.

[17]

A film forming method comprising sputtering the divided sputtering target according to any one of [1] to [16 ].

[18]

A method for producing a divided sputtering target according to any one of [1] to [16], comprising:

step a, a shielding material is configured on a back plate;

a step b of disposing a plurality of linear spacers for adjusting the thickness of the bonding material at positions on the back plate that do not overlap the masking material;

a step c of heating the shielding material, the backing plate on which the linear spacer is arranged, and the plurality of flat sputtering target members, and applying a bonding material to each bonding surface;

a step d of bonding a shielding material, the backing plate on which the linear spacer is arranged, and the plurality of flat sputtering target members to each other with a molten bonding material;

and e, cooling to solidify the bonding material.

[19]

The method of manufacturing a divided sputtering target according to [18], wherein in the step b, the linear spacer is disposed so as to have a portion extending from a portion where the shielding material is not disposed in an outer peripheral side surface of the predetermined sputtering target member disposed on the linear spacer in a plan view, and the extended portion is temporarily fixed to the backing plate at a position where the extended portion does not overlap with the predetermined sputtering target member disposed.

[20]

The method of manufacturing a divided sputtering target according to [19], further comprising cutting and removing the extended portion so that a cut surface is located directly below a portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed, after the step e is performed.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one embodiment of the present invention, when the divided sputtering target is used, the composition components of the backing plate can be prevented from being mixed into the sputtered film.

In addition, according to one embodiment of the present invention, the thickness of the bonding material for bonding each of the divided sputtering target members can be easily controlled. Therefore, the upper surface height between the plurality of sputtering target members can be easily made uniform. That is, it is easy to manufacture divided sputtering targets in which the heights of the upper surfaces are not varied or fluctuated but on the same plane between a plurality of sputtering target members. This is expected to suppress nodules and particles during sputtering. Further, since there is no variation in heat transfer characteristics among the plurality of sputtering targets, it is expected that the respective sputtering target members constituting the divided sputtering targets are less likely to break.

Therefore, according to an embodiment of the present invention, a divided sputtering target contributing to increase in area of a sputtered film can be provided. It is considered that the divided sputtering target can greatly contribute to industrial production of large display devices such as large liquid crystal displays and large organic EL displays.

Drawings

Fig. 1 is a schematic plan view showing a divided sputtering target according to an embodiment of the present invention.

Fig. 2 is a schematic sectional view showing a divided sputtering target according to an embodiment of the present invention cut in a thickness direction.

Fig. 3 is a schematic sectional view for explaining a method of manufacturing a divided sputtering target according to an embodiment of the present invention.

Fig. 4 is a schematic plan view showing a state in which a plurality of linear spacers are temporarily fixed using an adhesive tape before a plurality of flat plate-shaped sputtering target members are joined in the process of manufacturing the divided sputtering target of the embodiment of fig. 1.

Fig. 5-1 is a schematic plan view showing before peeling off the temporary fixing tape in the process of manufacturing the divided sputtering target of example 1.

Fig. 5-2 is a schematic top view of the divided sputtering target of example 1.

Fig. 6-1 is a schematic plan view showing the divided sputtering target of example 2 before the temporary fixing tape is peeled off.

Figure 6-2 is a schematic top view of the segmented sputtering target of example 2.

Fig. 7-1 is a schematic plan view showing the divided sputtering target of example 3 before the temporary fixing tape is peeled off.

FIG. 7-2 is a schematic top view of the segmented sputtering target of example 3.

Fig. 8-1 is a schematic plan view showing the divided sputtering target of example 4 before the temporary fixing tape is peeled off.

Figure 8-2 is a schematic top view of the segmented sputtering target of example 4.

Fig. 9-1 is a schematic plan view showing the divided sputtering target of example 5 before the temporary fixing tape is peeled off.

FIG. 9-2 is a schematic top view of the segmented sputtering target of example 5.

Fig. 10-1 is a schematic plan view showing the divided sputtering target of example 6 before the temporary fixing tape is peeled off.

FIG. 10-2 is a schematic top view of the divided sputtering target of example 6.

Fig. 11 is a schematic plan view of a divided sputtering target of example 7.

Fig. 12 is a schematic plan view of the divided sputtering target of comparative example 1.

Fig. 13 is a schematic plan view of the divided sputtering target of comparative example 2.

Fig. 14 is a flaw detection diagram showing the arrangement of a plurality of linear spacers in the divided sputtering target of example 4.

Detailed Description

(A. Divided sputtering target >

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 shows a schematic plan view of a divided sputtering target (100) according to an embodiment of the present invention. Fig. 2 is a schematic sectional view of a divided sputtering target (100) according to an embodiment of the present invention cut in the thickness direction.

A divided sputtering target (100) according to an embodiment of the present invention includes:

a plurality of flat plate-like sputtering target members (104) arranged on a backing plate (102) with a gap (103) therebetween,

a bonding material (106) disposed between the backing plate (102) and each sputtering target member (104),

a shielding material (108) disposed in the gap (103) between adjacent sputtering target members (104),

a plurality of linear spacers (110) (110a, 110b,110c, 110d) are arranged between the backing plate (102) and each sputtering target member (104) at positions not overlapping the shielding material (108) and adjust the thickness of the bonding material (106).

(1. Backboard)

The backing plate is joined to the sputtering target member to thereby function to improve the structural strength of the divided sputtering target. In particular, when the sputtering target member is formed of a relatively brittle substance such as ceramic, the use of the backing plate is particularly advantageous. The material forming the back plate is preferably a metal from the viewpoint of strength, and examples thereof include aluminum, aluminum alloys, stainless steel, copper and copper alloys, titanium, tungsten, molybdenum, and the like. Among these, particularly in the case of using a backing plate made of a highly conductive metal such as copper, the backing plate is exposed in the gap between the targets, and abnormality during sputtering is conspicuous, so that a bonding method using a shielding material is effective.

In one embodiment, the back plate may be flat. The shape of the back plate in plan view is not particularly limited, and may be, for example, a polygon, typically a quadrangle, and more typically a rectangle. The respective vertices of the polygon can be chamfered as appropriate.

The thickness of the backing plate is not particularly limited as long as it is appropriately set according to the structural strength, weight, and size of the divided sputtering target, and may be, for example, 3 to 30mm, and typically 5 to 20mm.

(2. Sputtering target member)

A plurality of flat plate-like sputtering target members can be arranged on the backing plate with a gap therebetween. The arrangement method is not particularly limited, and the plurality of flat plate-like sputtering target members can be arranged on the backing plate in, for example, M rows × N columns (M is a natural number of 2 or more, and N is a natural number of 1 or more). Among them, the plurality of flat plate-shaped sputtering target members are preferably arranged in 2 rows × N columns (N is a natural number of 1 or more) from the viewpoint of easily temporarily fixing all the linear spacers arranged below the plurality of flat plate-shaped sputtering target members. A temporary fixing method of the linear spacer is described below. From the viewpoint of facilitating the increase in size of the divided sputtering target, it is more preferable to arrange the divided sputtering targets in 2 rows × N columns (N is a natural number of 2 or more).

The gap (clearance) between adjacent sputtering target members can be formed linearly in a plan view, and is preferably formed linearly in a plan view. For example, when 4 flat plate-like sputtering target members are arranged in 2 rows × 2 columns on the backing plate, two linear spaces (gaps) are preferably formed in a cross shape in a plan view. In general, when 4 or more flat plate-like sputtering target members are arranged on a backing plate in M rows × N columns (M is a natural number of 2 or more, and N is a natural number of 2 or more), it is preferable to form (M-1) × (N-1) linear spaces (gaps) and (M-1) × (N-1) cross-shaped intersections in a plan view.

The smaller the gap (clearance) is, the more preferable from the viewpoint of reducing the sputtering trouble such as the nodule and the arc and making the film characteristics uniform, and therefore the gap is preferably 1.0mm or less, more preferably 0.7mm or less, and still more preferably 0.5mm or less at any position. However, when the interval (gap) between adjacent sputtering target members is too narrow, there is a risk that the target will peel off when an operation of removing the bonding material such as In solidified In the gap after bonding is performed In the manufacturing step, and the target will thermally expand when sputtering the target, and at this time, the end faces of the sputtering target members facing each other will come into contact, and the sputtering target members will break, and therefore the interval (gap) between the adjacent sputtering target members at any position is preferably 0.2mm or more, and more preferably 0.3mm or more.

The shape, size, and material of the plurality of flat plate-like sputtering target members may be different from each other, and may be partially the same or entirely the same. However, the shape, size, and material of the plurality of flat plate-shaped sputtering target members are preferably all the same for the reason of reducing cracking during sputtering by reducing sputtering failures such as nodules and arcing, making the film characteristics uniform, and making the thermal expansion characteristics uniform.

The shape of each flat sputtering target member in plan view is not particularly limited, and may be, for example, a polygon, typically a quadrangle, and more typically a rectangle. Each vertex of the polygon can be chamfered appropriately.

The size of each flat plate-like sputtering target member in a plan view may be appropriately set according to the material, strength, and thickness of each sputtering target member, and is not particularly limited, and may be, for example, 100 to 10000cm ² And typically can be 500 to 5000cm ² 。

The material of each sputtering target member is not particularly limited, and includes: semiconductor material of silicon (Si) or germanium (Ge), al ₂ O ₃ 、PZT(Pb(Zr、Ti)O ₃ )、HfO ₂ ，La ₂ O ₃ Oxide ceramics such as MgO, ITO, IZO, ZTO, ITZO and IGZO, metal materials such as titanium, indium, vanadium, zirconium, molybdenum and tungsten, and borides (e.g., tiB) ₂ 、CrB ₂ WB), carbide (example: WC, tiW, siC), nitride (example: tiN, alN), silicide (example: tiSi ₂ 、CrSi ₂ ) And non-oxide ceramics. These sputtering target members may be formed individually, or two or more kinds may be mixed to form each sputtering target member. In addition, in the case of an oxide semiconductor target, the conductive backing plate is exposed in the gap between adjacent sputtering targets, as compared with a target for a transparent conductive film, and therefore the characteristics of the sputtered film are more likely to be uneven. Therefore, as a material of each sputtering target member, an oxide semiconductor such as ITZO and IGZO can be suitably used in particular. Each sputtering target member may contain other components.

(3. Joining Material)

The bonding material is disposed between the backing plate and each sputtering target member, thereby playing a role of bonding the backing plate and each sputtering target member. The material of the bonding material can be appropriately selected In consideration of the material of the backing plate and each sputtering target member, and for example, low melting point metals (for example, melting point 130 to 250 ℃) having good thermal conductivity and electrical conductivity, such as In, in-Sn alloys (for example, sn 60 to 90 at%), sn-Ag alloys (for example, ag 3 to 20 at%), and Pb-Sn alloys (for example, sn 50 to 95 at%), can be used.

The bonding material is preferably not present in the gap between adjacent sputtering target members. If the bonding material is present in the gap between the adjacent sputtering target members, the bonding material may be sputtered during sputtering, and the material constituting the bonding material may be mixed in the sputtered film.

(4. Masking Material)

The shielding material is disposed in the gap between the adjacent sputtering target members, and thus can function to prevent the backing plate from being exposed in the gap. This prevents the backing plate from being sputtered during sputtering, and allows the material (typically copper) constituting the backing plate to be mixed into the sputtered film. In a preferred embodiment, the bonding material is not present in the gap, but the shielding material is exposed.

The minimum effect of the present invention can be obtained if the material of the shielding material is less likely to be sputtered than the components constituting the back plate. Further, the material of the shielding material is preferably low in reactivity with the bonding material, and when an oxide semiconductor is formed, even if a slight amount of the shielding material is mixed into the oxide semiconductor thin film to be formed, the TFT element characteristics can be less affected than those of Cu.

For example, zn, ti, or Sn may be used as a material of the shielding material, or an alloy containing 80 mass% or more of Zn, ti, and Sn may be used. In this way, when the shielding material is made of a metal material, the shielding material can be provided in the form of, for example, a metal foil.

However, in order to prevent the backing plate component from being sputtered and mixed into the sputtered film during sputtering, the material of the shielding material is preferably insulating. Examples of the insulating material include ceramics and resins. When the shielding material is ceramic or resin, the shielding material may be provided in the form of a sheet, for example. The ceramic is not particularly limited, and examples thereof include alumina, silica, magnesia and zirconia. The resin is not particularly limited, and examples thereof include a phenol resin, a melamine resin, an epoxy resin, a urea resin, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyvinyl acetate, an ABS resin, an AS resin, an acrylic resin, polyacetal, polycarbonate, modified polyphenylene ether (PPE), polybutylene terephthalate, polyarylate, polysulfone, polyphenylene sulfide, polyether ether ketone, a polyimide resin, a polyamideimide resin, and a fluororesin. The masking material may be used alone or in combination of two or more. Among them, polyamide-imide resins and polyimide resins are preferable, and polyamide-imide resins are more preferable, for reasons of hardness, strength, and easiness of purchase.

Referring to fig. 2, the upper surface of the shielding material (108) is located below the lower surface of each sputtering target member (104), and the bonding material (106) is preferably interposed between the upper surface of the shielding material (108) and the lower surface of each sputtering target member (104). In this case, the bonding material is not directly contacted with the shielding material, but the entire lower surface of the sputtering target member is directly contacted with the bonding material, and therefore, when the thermal conductivity of the shielding material is low, such as when an insulating shielding material is used, the thermal conductivity from the backing plate to the sputtering target member is improved. Further, since the shielding material is located below the lower surface of each sputtering target member, the plasma hardly reaches the shielding material during sputtering, and an effect that the shielding material is hardly sputtered can be obtained.

The width of the masking material is the same as or larger than the interval between adjacent sputtering target members, and the latter is more preferable. In other words, in the divided sputtering target in plan view, it is preferable that the shielding material is advanced more inward than the side edges of the adjacent sputtering target members facing each other. Thus, the region of the back plate shielded by the shielding material is larger than the above-described interval, and therefore the possibility of the back plate being sputtered can be further reduced.

The lower limit of the thickness of the masking material is preferably 0.1mm or more, and more preferably 0.3mm or more, from the viewpoint of the strength of the masking material and the shape at the time of maintenance operation. The upper limit of the thickness of the shielding material is preferably 1.0mm or less, more preferably 0.7mm or less, and still more preferably 0.5mm or less, from the viewpoint of suppressing deterioration of the thermal conductivity of the target.

(5. Linear spacer)

And a plurality of linear spacers arranged between the backing plate and each sputtering target member for adjusting the thickness of the bonding material. By using the linear spacer, there is an advantage that the sputtering target member is hard to break when the sputtering target member is placed thereon. For example, in the case of using a plate-shaped spacer, there are the following problems: since a local stress is applied from the edge portion of the spacer toward the back surface of the sputtering target member, the sputtering target member is easily broken during the cooling process after bonding and during sputtering, starting from the position to which the local stress is applied. On the other hand, since the linear spacer has a relatively round shape such as a circle, an ellipse, or an oval in cross section, the arrangement of the sputtering target member on the spacer makes it difficult for local stress to be applied to the back surface of the sputtering target member, and also makes it possible to obtain a cushioning effect by the bonding material present around the linear spacer. Therefore, by using the linear spacer, the sputtering target member is less likely to be broken when the sputtering target member is placed on the spacer.

From the viewpoint of reducing the local stress applied to the back surface of the sputtering target member, the lower limit of the diameter of each of the plurality of linear spacers is preferably 0.1mm or more, more preferably 0.3mm or more, and still more preferably 0.5mm or more. The upper limit of the diameter of each of the plurality of linear spacers is preferably 1.0mm or less, and more preferably 0.7mm or less, from the viewpoint of not deteriorating the heat transfer efficiency between the backing plate and the target. Here, the diameter of each linear spacer means a circle-equivalent diameter, that is, a diameter of a circle having a cross-sectional area equal to that of the linear spacer.

The length of each of the plurality of linear spacers (110) in the thickness direction of the shielding material (equal to the diameter of a circle when the cross section of the linear spacer is circular) is preferably larger than the thickness of the shielding material (108) (see fig. 2). The following structure described above can thereby be easily achieved: the upper surface of the shielding material (108) is located below the lower surface of each sputtering target member (104), and the bonding material (106) is interposed between the upper surface of the shielding material (108) and the lower surface of each sputtering target member (104). In order to avoid the risk that the height of the target is defined by the thickness of the shielding material, the length of each of the plurality of linear spacers in the thickness direction of the shielding material is preferably more than 0.1mm, more preferably more than 0.2mm, than the thickness of the shielding material. Since the heat transfer efficiency is deteriorated if the thickness of the bonding material between the target and the backing plate is too thick, the thickness of each of the plurality of linear spacers in the thickness direction of the shielding material is preferably 1.0mm or less, more preferably 0.5mm or less.

The linear spacer is preferably disposed at a position not overlapping the shielding material. If the linear spacer is disposed at a position overlapping the shielding material, that is, if the linear spacer is disposed above the shielding material or conversely below the shielding material, the sputtering surface of the sputtering target member disposed above the linear spacer is likely to be inclined with respect to the surface of the backing plate, making it difficult to manufacture a divided sputtering target having an upper surface on the same plane without height difference or undulation between a plurality of sputtering target members. Further, it is difficult to adjust the gap between the sputtering target members, and there is a problem that the gap between the sputtering target members is locally formed at a position where the gap is small, and the sputtering target members are easily broken at the time of sputtering.

The linear spacer is preferably made of a material having high heat transfer characteristics so as not to hinder heat transfer between the backing plate and the sputtering target member. In addition, in order to facilitate handling during the bonding operation, a material that is hard and non-plastic should be avoided as much as possible. From this viewpoint, the material of the linear spacer is preferably a metal selected from the group consisting of copper, titanium, iron, aluminum, nickel, and chromium, or an alloy containing one or more of these metals, more preferably copper, titanium, and aluminum, and still more preferably copper.

Preferably, each of the plurality of linear spacers does not have a portion extending from the outer peripheral side surface of the sputtering target member when the sputtering target is divided in a plan view. This is to prevent the linear spacer from being sputtered to give an unexpected negative effect on the characteristics of the sputtered film.

In the case where a specific one of the linear spacers does not have a portion extending from the outer peripheral side surface of the sputtering target member, both ends of the linear spacer disposed below the flat plate-shaped sputtering target member in a plan view of the flat plate-shaped sputtering target member can be disposed as follows, for example.

(1) A method of arranging both ends of one linear spacer at positions inside the outer peripheral side surface of the flat plate-like sputtering target member (see the linear spacer denoted by reference numeral 110c in fig. 1).

(2) The method of arranging the both ends of one linear spacer directly below (on the same plane as) the portion of the outer peripheral side surface of the sputtering target member where the shielding material is not arranged (see the linear spacers denoted by

reference numerals

110a,110b, and 110d in fig. 1).

(3) And a method of arranging one end of one linear spacer inside the outer peripheral side surface of the flat plate-shaped sputtering target member and the other end of the linear spacer directly below (on the same plane as) the portion of the outer peripheral side surface of the sputtering target member where the shielding material is not arranged.

Among these methods, the methods (2) and (3) are preferable, and the method (2) is more preferable, from the viewpoint that the linear spacer does not extend from the outer peripheral side surface of the sputtering target member and can be stably arranged at a predetermined position.

In the case of the method (1), since both ends of the linear spacer are positioned inside the outer peripheral side surface of the sputtering target member, it is difficult to temporarily fix the linear spacer at the time of positioning the linear spacer. Therefore, the linear spacer is at risk of deviating from a predetermined position.

In the case of the method (3), the linear spacer is disposed such that one end thereof is positioned directly below (on the same plane as) a portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed. Such an end can be formed as follows: starting to arrange the sputtering target member so as to extend from the outer peripheral side surface of the sputtering target member, which is to be arranged on the linear spacer, in a plan view, and temporarily fixing the sputtering target member to the backing plate by the extended end portion, and then cutting and removing the extended end portion; therefore, the advantage of higher positioning accuracy can be obtained as compared with the method (1). However, in the case of the method (3), since the other end portion of the linear spacer is located inside the outer peripheral side surface of the flat plate-shaped sputtering target member and cannot be temporarily fixed, the linear spacer may be displaced from a predetermined position.

In the case of the method (2), both ends of the linear spacer are disposed directly below (on the same plane as) the portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed. In this case, both ends of the linear spacer can be formed as follows: the sputtering target member is initially arranged so as to extend from the outer peripheral side surface of the sputtering target member which is to be arranged on the linear spacer in a plan view, and is temporarily fixed to the backing plate by the extended end portion, and then the extended end portion is cut and removed. Therefore, an advantage of further improving the positioning accuracy as compared with the method of (3) can be obtained. Preferably, all the linear spacers are arranged according to the method (2). In order to arrange all the linear spacers according to the method (2), the sputtering target members are preferably arranged in 2 rows × N columns (N is a natural number of 1 or more).

A more specific method of disposing the linear spacer by the method (2) will be exemplarily described. The method comprises the following steps: when at least one of the plurality of flat plate-shaped sputtering target members is seen as a rectangle in plan view, at least one of the plurality of linear spacers is disposed such that both ends thereof are positioned directly below an outer peripheral side surface of one of four sides constituting the at least one sputtering target member that is seen as a rectangle in plan view. In this case, in order to more effectively prevent the positional deviation of the linear pad spacer, the linear pad spacer is preferably bent and arranged between the backing plate and the sputtering target member in a V-shape in plan view (see the linear pad spacer denoted by reference numeral 110a in fig. 1) whose tip becomes thinner as it is separated from both ends, or bent and arranged in an equilateral trapezoid in plan view (see the linear pad spacer denoted by reference numeral 110d in fig. 1) whose tip becomes thinner as it is separated from both ends. The former method is more preferable because the effect of preventing the linear spacer from being displaced is more excellent.

The linear spacer is preferably arranged so as to be able to stably mount the flat sputtering target member. Therefore, when the linear pad spacer is disposed between the backing plate and the sputtering target member so that both ends thereof are positioned directly below the outer peripheral side surface of one of the four sides constituting the rectangular sputtering target member in plan view, such as when the linear pad spacer is bent and disposed in a V-shape in plan view whose tip end is tapered as it is separated from both ends, or when the linear pad spacer is bent and disposed in a trapezoidal shape in plan view whose tip end is tapered as it is separated from both ends, it is preferable that the linear pad spacer is disposed so that the center of gravity of the sputtering target member is positioned inside the figure (for example, V-shape or trapezoidal shape) drawn by the linear pad spacer (see the linear pad spacers denoted by

reference numerals

110a and 110d in fig. 1).

A more specific method of disposing the linear spacer by the method of (2) will be described as an example. The method includes: when at least one of the plurality of flat plate-shaped sputtering target members is rectangular in plan view, the arrangement is performed such that each end of at least one of the plurality of linear spacers is positioned directly below each outer peripheral side surface of two adjacent sides among the four sides constituting the at least one rectangular sputtering target member in plan view (see the linear spacer denoted by reference numeral 110b in fig. 1). In this case, the linear spacer may be disposed between the backing plate and the at least one sputtering target member having a rectangular shape in plan view in an L shape (see reference numeral 110b in fig. 1).

In this case, the linear spacer is also preferably arranged so as to stably support the flat plate-like sputtering target member. From this viewpoint, it is preferable that each of the ends of at least two linear spacer members is positioned directly below each of the outer peripheral side surfaces of two adjacent sides out of the four sides constituting one rectangular sputtering target member in a plan view, and the two linear spacer members are arranged so as to sandwich the center of gravity of the sputtering target member (see reference numeral 110b in fig. 1).

< B. method for manufacturing divided sputtering target

The method for manufacturing a divided sputtering target according to an embodiment of the present invention includes, for example, the steps of:

step a (FIG. 3 a), disposing a masking material (108) on a backing plate (102),

step b (FIG. 3 b) of disposing a plurality of linear spacers (110) for adjusting the thickness of the bonding material (106) at positions on the back plate (102) that do not overlap the masking material (108),

step c (FIG. 3 c) of heating the shielding material (106), the backing plate (102) on which the linear spacer (110) is arranged, and the plurality of flat sputtering target members (104) and applying the bonding material (106) to the bonding surfaces,

step d (FIG. 3 d) of bonding a shielding material 108, the backing plate 102 having the linear spacers 110 arranged thereon, and the flat sputtering target member 104 with the molten bonding material 106,

and e, cooling to solidify the bonding material (106).

In step b, the linear spacer is preferably arranged to have a portion extending from a portion of the outer peripheral side surface of the sputtering target member, which is to be arranged on the linear spacer, where the shielding material is not arranged, in a plan view, and the extended portion is temporarily fixed to the backing plate at a position not overlapping with the sputtering target member to be arranged. This is to improve the positional accuracy of the linear spacer. The method of temporary fixation is not particularly limited, and for example, a method of temporarily fixing the extended portion of the linear spacer to the back plate using an adhesive tape is exemplified. The tape preferably does not damage the backing sheet and can be easily peeled off. Fig. 4 is a schematic plan view showing a state in which a plurality of linear spacers are temporarily fixed by an adhesive tape (109) before a plurality of flat plate-shaped sputtering target members are bonded by a bonding material in step b of manufacturing the divided sputtering target according to the embodiment of fig. 1.

In step c, any known method can be used as a method of applying the bonding material to the bonding surfaces of the backing plate and the plurality of flat sputtering target members. For example, ultrasonic welding, plating, vapor deposition, and the like can be cited. Among them, ultrasonic welding is preferable because of high bonding strength.

Preferably, after step e is performed, the extended portion of the linear spacer used for temporary fixation is cut and removed. Specifically, the extended portion is cut and removed so that the cut surface of the linear spacer is positioned directly below the portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed. When the shielding material protrudes from the outer peripheral side surface of each sputtering target member, the protruding portion is preferably cut and removed. Thereby, the cut surface of the shielding material is positioned directly below (on the same plane as) the outer peripheral side surface of the sputtering target member.

After step e, a step of removing the bonding material (106) exposed in the space between the adjacent sputtering target members and exposing the shielding material (108) is preferably further performed (fig. 3 e). As a method of removing the bonding material, for example, a method of digging by using a clearance bonding material removing jig is cited. As the gap bonding material removing jig, a jig having a sharp cutter can be used so that the bonding material fitted into the gap between the adjacent sputtering target members can be scooped up. The tip of the cutter is preferably hook-shaped in order to efficiently scoop the joining material. The gap bonding material removing jig may be made of, for example, metal (for example, stainless steel), and PEEK (polyetheretherketone, etc.) that does not damage the back plate may be used. From the viewpoint of improving the workability of removing the bonding material and the production efficiency, the removal of the bonding material is preferably performed at a temperature of 80 to 150 ℃, more preferably at a temperature of 90 to 130 ℃, and still more preferably at a temperature of 100 to 120 ℃ when the bonding material is cooled. If the temperature of the bonding material is too low, the bonding material may become hard and the operability of the removing operation may deteriorate.

< C. film formation method >

According to an embodiment of the present invention, there is provided a film formation method including sputtering a divided sputtering target. The sputtering method is not limited, and an RF magnetron sputtering method, a DC magnetron sputtering method, an AC magnetron sputtering method, a pulsed DC magnetron sputtering method, or the like can be suitably used.

[ examples ] A

Hereinafter, the embodiments are shown for easy understanding of the present invention and advantages thereof, but the present invention is not limited to the embodiments.

< 1. Fabrication of divided sputtering target >

(Back plate)

Rectangular copper back plates in plan view having the dimensions shown in table 1 were prepared in accordance with the test numbers.

(masking Material)

As a masking material, a polyamideimide resin sheet (thickness 0.3 mm) having a product name of TPS TI-5013 manufactured by Toray plastics Seiko Co., ltd was prepared.

(spacer)

As a linear spacer, a copper wire having a circular cross section with a diameter of 0.5mm was prepared.

As a plate-like spacer, a copper plate 20mm in length, 10mm in width and 0.5mm in thickness was prepared.

(joining Material)

As a bonding material, indium metal was prepared.

(sputtering target Member)

As a sputtering target member, a rectangular plate-shaped sputtering target member of IGZO having a length of 63mm, a width of 254mm and a thickness of 6mm was prepared.

(examples 1 to 7)

A masking material (108) is arranged or fixed on a back plate (102) by a double-sided tape (product name double-sided Kapton tape manufactured by Temple John), and a plurality of linear spacers (110) for adjusting the thickness of a joining material (106) are arranged at positions on the back plate (102) which do not overlap with the masking material (108).

Next, in examples 1 to 6, the linear spacer (110) was disposed so as to have a portion extending from a portion of the outer peripheral side surface of the sputtering target member (104) which is to be disposed above the linear spacer and to which no shielding material is disposed in a plan view, and the extended portion was temporarily fixed to the backing plate at a position which does not overlap with the sputtering target member which is to be disposed (see fig. 5-1, 6-1, 7-1, 8-1, 9-1, and 10-1). One-sided tape (manufactured by Temple Jordan Co., ltd., product name Kapton tape) was used for temporary fixation. In example 7, temporary fixation was not performed.

Then, a masking material (108), a backing plate (102) on which a linear spacer (110) is arranged, and a plurality of flat plate-shaped sputtering target members (104) corresponding to the test numbers are heated, and a bonding material (106) is applied to each bonding surface by ultrasonic welding.

Then, a shielding material (108), the backing plate (102) on which the linear spacers (110) are arranged, and a plurality of flat sputtering target members (104) are bonded together by the melted bonding material (106), and then the bonding material (106) is solidified by cooling. In the cooling of the bonding material, when the bonding material is in the range of 80-150 ℃, the bonding material (106) exposed in the space (103) between the adjacent sputtering target members (104) is removed by a digging method by using a gap bonding material removing jig made of SUS, and the shielding material (108) is exposed. Next, in examples 1 to 6, the extended portion of the linear spacer (108) used in the temporary fixing was cut and removed by a cutter or the like so that the cut surface was located directly below the portion of the outer peripheral side surface of the sputtering target where the shielding material was not disposed, and then the tape was peeled off. In addition, the shielding material is also cut at the portion protruding from the outer peripheral side surface.

Thus, divided sputtering targets of examples 1 to 7 in which a plurality of sputtering target members were arranged were produced by the method described in Table 1 (see FIGS. 5-2, 6-2, 7-2, 8-2, 9-2, 10-2, and 11).

Comparative example 1

A masking material (108) is disposed or fixed on a back plate (102) by a double-sided tape (product name of temple manufacture is double-sided Kapton tape), and a plurality of plate-shaped spacers (110) for adjusting the thickness of a joining material (106) are disposed at positions on the back plate (102) that do not overlap with the masking material (108). At this time, the plate-shaped spacer (110) is fixed to the back plate by an adhesive.

Then, a shielding material (108), a backing plate (102) on which a plate-shaped spacer (110) is arranged, and a plurality of flat plate-shaped sputtering target members (104) are heated, and a bonding material (106) is applied to each bonding surface by ultrasonic welding.

Then, a shielding material (108), the backing plate (102) on which the plate-shaped spacer (110) is arranged, and a plurality of flat plate-shaped sputtering target members (104) are bonded together by the melted bonding material (106), and then, the bonding material (106) is solidified by cooling.

Then, the bonding material (106) exposed in the space (103) between the adjacent sputtering target members (104) is removed by a scooping method using a gap bonding material removal jig made of SUS, and the shielding material (108) is exposed.

Thus, a divided sputtering target of comparative example 1 in which a plurality of sputtering target members are arranged was produced by the method described in table 1 (see fig. 12).

Comparative example 2

A masking material (108) is disposed on the backplate (102).

Then, the backing plate (102) on which the shielding material (108) is disposed and the plurality of flat plate-like sputtering target members (104) are heated, and the bonding surfaces are coated with a bonding material (106) by ultrasonic welding.

Then, the backing plate (102) on which the shielding material (108) is disposed is bonded to a plurality of flat plate-shaped sputtering target members (104) with the molten bonding material (106), and then the bonding material (106) is solidified by cooling.

Thus, a divided sputtering target of comparative example 2 in which a plurality of sputtering target members were arranged was produced by the method described in table 1 (see fig. 13).

< 2. Evaluation of characteristics >

The divided sputtering targets of examples and comparative examples prepared in the above procedure were evaluated as follows. The results are shown in table 1.

(1) Presence or absence of cracking

Each of the divided sputtering targets was set in a sputtering apparatus, magnetron sputtering was performed at an input power of 1.5kW, and film formation was performed on a glass substrate for 50 minutes. Then, the presence or absence of cracking of each sputtering target member was visually confirmed. The evaluation was carried out according to the following criteria.

5: no cracking was observed.

3: although no cracking was observed in this test, since there was no bonding material between the target member and the masking material, the thermal conductivity locally deteriorated, and there was a risk of cracking the target.

1: cracking occurs.

(2) Evaluation of height difference

By the height difference measurement using the depth gauge, the height difference of the facing sides of the sputtering target members adjacent to each other (height difference of the joint) among the plurality of sputtering target members is determined. The measured height difference was evaluated according to the following criteria.

5: very good (all measurement positions (all joints) are less than 0.05 mm)

4: good (all measurement positions are less than 0.10 mm)

3: within standard (all measurement positions are less than 0.20 mm)

2: outside standard (with 1 place more than 0.20 mm)

1: outside standard (more than 0.20mm in many places)

(3) Positional offset of spacer

Flaw detection patterns were obtained by visual inspection and ultrasonic flaw detection according to the following criteria, and evaluated.

5: the spacer is substantially free from deviation from the target position

4: the spacer is only slightly offset from the target position

3: although the spacer is easily deviated from the target position, the following criteria are satisfied

Reference: none of the following phenomena (a) to (B) was observed.

(A) The spacers overlap the masking material.

(B) The spacer extends beyond the outer side of the sputtering target member.

For reference, fig. 14 shows a flaw detection diagram showing the arrangement of a plurality of linear spacers in the divided sputtering target of example 4.

< 3. Investigation >

In comparative example 1, since no spacer was used, the 2 sides of the sputtering target member near the four-corner side of the backing plate where no masking material was disposed tended to sink, and the evaluation of the level difference was not good.

In comparative example 2, since the plate-shaped spacer was used, a local stress was applied from the edge portion of the spacer toward the back surface of the sputtering target member, and the sputtering target member was broken.

On the other hand, in examples 1 to 7, the use of the linear spacers can suppress cracking and reduce the level difference. In particular, in examples 1 to 5 in which both ends of the wire were temporarily fixed, the positional deviation of the spacer was small, and the operability was excellent.

[ TABLE 1]

Description of the reference numerals

100. Segmented sputter target

102. Back plate

103. Gap

104. Sputtering target member

106. Bonding material

108. Masking material

109. Adhesive tape

110 (110 a,110b,110c,110 d) Linear spacer

Claims

1. A divided sputtering target is provided with:

a plurality of flat sputtering target members arranged on the backing plate with a gap therebetween,

a bonding material disposed between the backing plate and each sputtering target member,

a shielding material disposed in the gap between adjacent sputtering target members,

a plurality of linear spacers arranged between the backing plate and each sputtering target member at positions not overlapping the shielding material for adjusting the thickness of the bonding material,

one end or both ends of at least one of the plurality of linear spacers are positioned directly below a portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed,

at least one of the plurality of flat plate-shaped sputtering target members is rectangular in plan view, and at least one of the plurality of linear spacers has both ends positioned directly below an outer peripheral side surface of one of four sides constituting the at least one sputtering target member rectangular in plan view, or each end is positioned directly below each outer peripheral side surface constituting two adjacent sides.

2. The split sputtering target according to claim 1, wherein none of the plurality of linear spacers has a portion extending from the outer peripheral side surface of the sputtering target member in a plan view.

3. The divided sputtering target according to claim 1, wherein at least one of the plurality of linear spacers has both ends located directly below an outer peripheral side surface of one of four sides constituting the at least one sputtering target member having a rectangular shape in plan view, and is disposed between the backing plate and the at least one sputtering target member having a rectangular shape in plan view in a V-shape in plan view in which a tip end thereof becomes narrower as it goes away from the both ends.

4. The divided sputtering target according to claim 1, wherein at least one of the plurality of linear spacers has both ends located directly below the outer peripheral side surface of one of the four sides constituting the at least one sputtering target member having a rectangular shape in plan view, and is arranged between the backing plate and the at least one sputtering target member having a rectangular shape in plan view in an equilateral trapezoid shape whose tip becomes narrower as it goes away from the both ends.

5. The divided sputtering target according to claim 1, wherein each end of at least one of the plurality of linear spacers is positioned directly below each of outer peripheral side surfaces of two adjacent sides among the four sides constituting the at least one rectangular sputtering target member viewed in plan, and is arranged in an L-shape in plan view between the backing plate and the at least one rectangular sputtering target member viewed in plan.

6. The divided sputtering target according to any one of claims 1 to 5, wherein the plurality of flat plate-like sputtering target members are formed of an oxide semiconductor.

7. The split sputtering target according to any one of claims 1 to 5, wherein the plurality of linear spacers have a diameter of 0.1mm to 1.0mm.

8. The split sputtering target according to any one of claims 1 to 5, wherein the material of the plurality of linear spacers is a metal selected from the group consisting of copper, titanium, iron, aluminum, nickel, and chromium, or an alloy containing one or more of the metals.

9. The divided sputtering target according to any one of claims 1 to 5, wherein the upper surface of the shielding material is located lower than the lower surface of each sputtering target member, and the bonding material is interposed between the upper surface of the shielding material and the lower surface of each sputtering target member.

10. The split sputtering target according to claim 9, wherein the length of the plurality of linear spacers in the thickness direction of the shielding material is larger than the thickness of the shielding material.

11. The divided sputtering target according to claim 9, wherein the width of the shielding material disposed in the gap is the same as or larger than the interval between the sputtering target members adjacent to each other.

12. The divided sputtering target according to any one of claims 1 to 5, wherein each of the plurality of flat plate-like sputtering target members is rectangular in plan view and is arranged in 2 rows by N columns on the backing plate, where N is a natural number of 1 or more.

13. The divided sputtering target according to any one of claims 1 to 5, wherein the material of the shielding material has an insulating property.

14. The segmented sputtering target according to any one of claims 1 to 5, wherein a masking material is exposed in the gap.

15. A film forming method comprising sputtering the divided sputtering target according to any one of claims 1 to 5.

16. A method for manufacturing the divided sputtering target according to any one of claims 1 to 5, comprising:

step a, a shielding material is configured on the back plate,

a step b of disposing a plurality of linear spacers for adjusting the thickness of the bonding material at positions on the back plate that do not overlap the masking material,

a step c of heating the shielding material, the backing plate on which the linear spacer is arranged, and the plurality of flat sputtering target members and applying a bonding material to each bonding surface,

a step d of bonding the shielding material, the backing plate on which the linear spacer is arranged, and the plurality of flat sputtering target members with the melted bonding material,

step e, cooling to solidify the bonding material,

wherein in step b, the linear spacer is arranged to have a portion extending from a portion of the outer peripheral side surface of the predetermined sputtering target member arranged above the linear spacer, on which the shielding material is not arranged, in a plan view, and the extended portion is temporarily fixed to the backing plate at a position not overlapping the predetermined sputtering target member arranged,

after the step e is performed, the extended portion is cut and removed so that a cut surface is located directly below a portion of the outer peripheral side surface of the sputtering target member where the shielding material is not disposed.