WO2018128634A1

WO2018128634A1 - Method, apparatus, and target for material deposition on a substrate in a vacuum deposition process

Info

Publication number: WO2018128634A1
Application number: PCT/US2017/012741
Authority: WO
Inventors: Aki HOSOKAWA
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2017-01-09
Filing date: 2017-01-09
Publication date: 2018-07-12
Anticipated expiration: 2019-07-09
Also published as: CN110312821B; CN110312821A

Abstract

The present disclosure provides a method for material deposition on a substrate in a vacuum deposition process having a sputtering target is provided. The method includes providing a target temperature of the sputtering target during operation to be within a desired target temperature range for adjusting a gap width of a gap of two adjacent target segments of the sputtering target.

Description

METHOD, APPARATUS, AND TARGET FOR MATERIAL DEPOSITION ON A SUBSTRATE IN A VACUUM DEPOSITION PROCESS

FIELD

[0001 ] Embodiments of the present disclosure relate to an apparatus for material deposition on a substrate in a vacuum deposition process, a system for sputter deposition on a substrate, and a method for material deposition on a substrate in a vacuum deposition process. Embodiments of the present disclosure particularly relate to sputter sources, such as sputtering cathodes or rotatable sputtering cathodes.

BACKGROUND

100021 Techniques for layer deposition on a substrate include, for example, sputter deposition, thermal evaporation, and chemical vapor deposition (CVD). A sputter deposition process can be used to deposit a material layer on the substrate, such as a layer of a conducting or an insulating material. During the sputter deposition process, a target having a target material to be deposited on the substrate is bombarded with ions generated in a plasma region to dislodge atoms of the target materi al from a surface of the target. The dislodged atoms can form the material layer on the substrate.

[0003] Coated substrates can be used, for example, in semiconductor devices and thin film batteries. As an example, substrates for displays can be coated using sputter deposition. Further applications include insulating panels, organic light emitting diode (OLED) panels, substrates with TFT, color filters or the like. Moreover, thin film batteries, such as lithium-ion batteries, are used in a growing number of applications, such as cell phones, notebooks and implantable medical devices.

[0004] For material deposition e.g. on large area substrates, large targets are beneficial . However, it can be challenging to make targets, such as ceramic targets, Indium Tin Oxide (ΓΓΟ) targets, and Indium Gallium. Zinc Oxide (IGZO) targets larger in size. Due to manufacturing difficulty, there is a limitation of target size, for example ceramic target size. Because of the size limitation, targets, such as ceramic targets, can be designed segmented. A segmented design may result in gaps between segments. For example, the target can be provided with a segmented design, i .e. several segments of the target material can be fixed on a target support, for example, using a bonding material. However, at an interface or joint between neighboring segments, particles can be generated, leading to a reduction in quality of the material layer deposited on the substrate. Further, the bonding material can leak from the interface or joint between neighboring segments, e.g., when temperature changes occur, leading to the occurrence of arcing.

[0005] In view of the above, new methods for material deposition on the substrate in a vacuum deposition process having a sputtering target, new apparatuses for material deposition on a substrate in a vacuum deposition process, and targets for material deposition on a substrate that overcome at least some of the problems in the art are beneficial. The present disclosure particularly aims at providing methods, apparatuses, and targets that can avoid the occurrence of arcing and/or particle generation, e.g., at interfaces between neighboring target segments.

SUMMARY

[0006] In light of the above, a method for material deposition on the substrate, an apparatus for material deposition on a substrate in a vacuum deposition process, and a target for material deposition on a substrate are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0007] According to one embodiment of the present disclosure, a method for material deposition on a substrate in a vacuum deposition process having a sputtering target is provided. The method includes providing a target temperature of the sputtering target during operation to be within a desired target temperature range for adjusting a gap width of a gap of two adjacent target segments of the sputtering target.

[0008] According to another embodiment of the present disclosure, a sputtering target for material deposition on a substrate in a vacuum deposition process is provided. The sputtering target includes three or more target segments, wherein a first target segment of the three or more target segments has a first segment length and a second target segment of the three or more target segments has a second segment length, wherein the second segment length is larger than the first segment length, and wherein a third target segment is provided having a third segment length larger than the first segment length, and a first gap width of a first gap between the first target segment and the second target segment and a second gap width of a second gap between the second target segment and a third target segment, wherein the first gap width is smaller than the second gap width, particularly at a first temperature lower than an operating temperature.

[0009] According to a further embodiment of the present disclosure, an apparatus for material deposition on a substrate in a vacuum deposition process is provided. The apparatus includes a vacuum chamber configured for housing one or more sputtering cathodes, a determining unit configured to determine a gap width of a gap of two adjacent target segments of the one or more sputtering cathodes during operation, and a control unit, wherein the control unit is configured to adjust a parameter adapted to change a temperature of a sputtering target.

[0010] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatus include methods aspects for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

100111 So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following: Fig. 1 schematically shows a sputtering cathode and a sputtering target according to embodiments described herein;

Fig. 2 schematically shows a section of another sputtering cathode and another sputtering target having two or more target segments and one or more gap widths between adjacent target segments according to embodiments described herein;

Fig. 3 A, 3B, and 3C schematically show- a partial view? of a section of another sputtering cathode and another sputtering target having two or more target segments and one or more gap widths between adjacent target segments according to embodiments described herein;

Fig. 4 shows a graph illustrating the effect of temperature changes on a target gap width;

Fig. 5 shows a flow chart of a method of sputtering target gap width adjustment according to embodiments described herein;

Fig. 6 shows another flow chart of a method of sputtering target gap width adjustment by providing a predetermined speed of rotation according to embodiments described herein;

Fig. 7 shows another flow chart of a method of sputtering target gap width adjustment by adjusting a cooling element according to embodiments described herein;

Fig. 8 shows another flow chart of a method of sputtering target gap width adjustment and gap width control according to embodiments described herein; Fig. 9 shows schematically a deposition apparatus according to embodiments described herein;

Fig. 10 shows schematically another deposition apparatus according to embodiments described herein; and

Fie. 1 1 shows schematically a cross sectional view of another

deposition apparatus according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0012] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0013] Embodiments of the present disclosure generally refer to a method for a segmented sputtering target in a vacuum material deposition process. Embodiments of the present disclosure adjust the gap width of a gap of two adjacent targeted segments, i.e. a gap between adjacent target segments, during operation of the material deposition process by providing a desired target temperature. Accordingly, the gap width is adjusted by providing a target temperature within a desired target temperature range. For example, adjusting the gap width may result in an adjusted gap width. The adjusted gap width can be 0.1 mm or below. The embodiments described herein can be utilized for sputter deposition on large area substrates, e.g., for lithium battery manufacturing, electrochromic windows and/or display manufacturing. [0014] Embodiments described herein may particularly relate to display manufacture on large area substrates. According to some embodiments, large area substrates or carriers supporting one or more substrates, i .e. large area carriers, may have a size of at least 0.174 m². Typically, the size of the carrier can be about 1.4 m to about 8 m², more typically about 2 m to about 9 m² or even up to 12 m². Typically, the rectangular area in which the substrates are supported, for which methods, apparatuses, and targets according to embodiments described herein are provided, are carriers having sizes for large area substrates as described herein. For instance, a large area carrier, which would correspond to an area of a single large area substrate, can be GEN 5, which corresponds to about 1.4 m² substrates (1.1 m x 1.3 m), GEN 7.5, which corresponds to about 4.29 m² substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7m² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m" substrates (2.85 m ^x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented.

[0015] FIG. 1 shows a sputtering cathode 100 having a sputtering target 120. FIG. l shows a backing tube 110. The sputtering target 120 may be for example a ceramic target, such as an Indium Tin Oxide (ΠΌ) target or an Indium Gallium Zinc Oxide (IGZO) target. Target segments 122 of the sputtering target 120 are coupled to the backing tube, i.e. a backing portion of the sputtering cathode 100. Coupling of the target segments to the backing portion may be performed by different methods, i.e. bonding or soldering with a material. The target segments and the backing portion, e.g. the backing tube, are coupled by a bonding material 130 or a soldering material. The bonding material may be for example an indium based alloy. Coupling may also be performed by methods generally described as welding, i .e. diffusion bonding. Alternatively, non-bonded targets can be provided, wherein for example a backing tube supports the target without a bonding material.

[0016] The sputtering cathode may further include a flange portion 140 provided at an end of the backing tube. The flange portion can be utilized to mount the sputtering cathode in a deposition apparatus. The flange portion may also be referred to as a mounting portion . According to some embodiments, one flange portion can be provided. A sputtering target mounted with one flange portion is provided in a cantilever state. Alternatively, flange portions can be provided at two ends of the backing tube. [0017] As the sputtering target comprises several target segments, adjacent target segments have a gap 180, wherein the target segments are spaced apart from each other. The gap 80 between adjacent target segments 122 has a gap width. The gap width of the gap may be too large which leads to deposition of target material into the gap or leads to generation of particles at the gap. Consequently, the quality of the deposition process is reduced. Furthermore, target segments can expand or contract due to temperature changes. A too narrow gap width may lead to a contact of adjacent target segments, which can cause damage to the sputtering target. Therefore, the gap width has to be in a certain range to avoid the above mentioned effects. With current manufacturing technology, the accuracy of the gap width control is not precise enough. If the gap width is not controlled precisely enough, unwanted re-deposition may go into the gap and/or particles may be generated.

[0 18] According to embodiments described herein a gap width of 0.1 mm or below may be provided. A gap width may be larger than zero. Target gap width can be controlled during sputtering at operating temperature, for example at an operating temperature of around 120°C. Precise gap width control may be considered beneficial to avoid the above mentioned particle generation and/or re-deposition and/or the above mentioned damaging of the target or damage to the target.

[0019] In the following description, reference is made to a method for a sputtering cathode for a material deposition apparatus. According to embodiments of the present disclosure, a method for material deposition on a substrate in a vacuum deposition chamber having a sputtering target is provided. The method includes providing a target temperature of the sputtering target during operation to be within a desired target temperature range for adjusting a gap width of a gap of two adjacent target segments of the sputtering target, i.e. a gap between adjacent target segments.

[0020] Figs. 3A, 3B, and 3C show a schematic cross-sectional view of a section of a sputtering target having a target segment 122 and a gap between two adjacent target segments 122. Exempiarily, Fig. 3 A depicts a gap width 312 of a gap 310, wherein said gap width is the gap width at a defined temperature of the sputtering target, for example room temperature. The gap width at the defined temperature of the sputtering target, for example room temperature, has a value that is not yet in the desired gap width range. For example, the gap width at the defined temperature of the sputtering target, for example room temperature, can be above 0.1 mm . The gap width 312, at for example, room temperature, may be therefore above 0.1 mm. A desired temperature range, e.g. possible operating temperatures, can be the temperature range in which the gap width is larger than zero and equal or smaller than 0.1 mm

[00211 The inventors have found that it is possible to adjust the gap width by providing an operation temperature in a predetermined temperature range. The predetermined temperature range can be defined by the gap width 312 at, for example, room temperature. During operation of the sputtering cathode, the target segments 122 of the sputtering target 120 expand due to thermal expansion. FIG. 3B exemplarily illustrates the effect on the gap width 314 due to a change of the temperature of the sputtering target. According to some embodiments, which can be combined with other embodiments of the present disclosure, a cost efficient and/or accessible way to change the temperature of the sputtering target is to change the speed of rotation of a rotary sputtering target. The method of gap width adjustment by changing the speed of rotation will be described in more detail below.

[0022] FIG. 3B shows a sputtering target 120 that is not bonded to the backing tube 110. In Fig. 3B the temperature of the sputtering target 120 is higher than the temperature of the sputtering target of FIG. 3A. Hie segment length of the target segments 122 is expanded due to the free expansion of the target segments. The target segment has expanded in longitudinal direction towards the gap 310. Due to the expansion, the gap width 314 of the gap between two adjacent target segments 122 is smaller than the gap width 312 shown in FIG. 3A. The temperature of the target segment 122 may be higher near the exposed surface 320 than the temperature near the backing tube 110. The target segment 122 may therefore expand differently in the longitudinal direction at different target heights. FIG. 3B shows a gap tapered in the radial direction due to unequal expansion.

[0023] FIG. 3C shows a sputtering target 120 bonded to the backing tube 1 10 by a material 130. The material 130 may restrict the expansion of the target segments 122 in longitudinal direction towards the gap 310. The expansion at a defined temperature is therefore smaller than the expansion of a target segment 122 that is not bonded to the backing tube 1 10. Due to the expansion, the gap width 316 of the gap of two adjacent target segments 122 is smaller than the gap width 312 shown in FIG. 3A. The temperature of the target segment 122 may be larger near the exposed surface 320 than the temperature near the backing tube 110. The target segment 122 may therefore expand differently in the longitudinal direction at different target heights.

10024] According to some embodiments, which can be combined with other embodiments described herein, the segment length of a target segment 122 is 100 mm or above. Particularly, a target segment may have a segment length from 150 mm to 1500 mm. More particularly, a target segment may have a segment length from 300 mm to 900 mm, such as for example about 450 mm.

[0025] A gap width within a desired range is provided by utilizing the thermal expansion during operation of the sputtering target 120. Adjacent target segments 122 expand due to thermal expansion. Expansion of the adjacent target segments 122 leads to a narrower gap. The gap width of a gap 1 80 of adjacent target segments 122 can be controlled by determining a desired target temperature range. The thermal expansion depends on the segment length 124. With an increasing segment length 124, the expansion of the target segment increases.

[0026] The expansion further depends on the temperature. Exemplarily, a target segment may have a certain segment length at a temperature Ti . At a temperature T₂ > Tj, the target segment has a larger segment length. The gap width at T₂ is smaller than the gap width at Ti due to the increased segment length at T₂. A desired target temperature T_D may be determined by the formula as follows:

(Wo - W_D)

7n +

(I] + L₂)^■ a^■ σ

[0027] A predetermined gap width W₀ is defined by the temperature To. To may be for example a temperature at room temperature. The gap width Wo is the width of the gap of two adjacent target segments with one target segment having the segment length Li and the other one having the segment length L₂. WD is the desired gap width, particularly, a gap width of 0.1 mm or below. The material of the sputtering target has a coefficient of thermal expansion a. Further, a parameter σ is included. The value of the parameter may vary from above 0 to 1 , for example the parameter may be about 0.5. In some embodiments, the parameter o may further consist of two or more sub-para neters. For example the parameter may consist of two sub-parameters oi and σ₂, wherein the first sub-pararneter may be fractional expansion of a target segment towards the gap in the longitudinal direction, which may be about 0.5, the second sub-parameter may be a restriction coefficient due to restricted expansion of a bonded target segment. This restriction coefficient, which can be considered a bonding parameter and which may, for example, be due to a bonding material constraint, can have a value of 0.5 to 0.8.

[0028] Fig. 5 shows a flow chart of a method according to embodiments described herein. By providing a target temperature (box 510), a gap width of a gap of two adjacent target segments, i.e. a gap between adjacent target segments, is adjusted (box 520). Accordingly, a method for material deposition on the substrate in a vacuum deposition process having a sputtering target includes providing a target temperature of the sputtering target during operation. The target temperature during operation is provided within a desired temperature range for adjusting the gap width, for example a gap width between two adjacent target segments of the sputtering target. The gap width at, for example, room temperature between target segments of a target is known or can be determined. The gap width at, for example, room temperature, i.e. a temperature before operation, which may have a difference in gap width when compared to a desired gap width, can be determined. Accordingly, a predetermined temperature window or temperature range, in which the gap width during operation is within a desired gap width range, can be determined . The manufacturing parameters can be chosen to have the desired temperature range and, thus, the desired gap width range.

[0029] FIG. 1 shows a sputtering cathode 100 having a rotary sputtering target 120. An inner diameter 190 defines an inner space 160 of the sputtering cathode. The sputtering cathode 100 can comprise a magnet assembly (1120 in FIG. 11) placed inside the inner space 160. Particularly, the magnet assembly is a magnet assembly for magnetron sputtering. Sputtering heats up the surface from which the sputtering material is released. In magnetron sputtering, the plasma is trapped within a magnetic field near the target area. The sputtering target 120 and the backing tube 1 10 have an axis of rotation . Further, the sputtering target 120 and backing tube 110 may rotate together around the magnet assembly. It has to be understood that a rotation of the sputtering target 120 implies a rotation of the backing tube 110. For reasons of simplicity, only the rotation of the sputtering target is explicitly stated in the following section.

[0030] According to some embodiments, which can be combined with other embodiments described herein, the desired target temperature range is provided by a speed of rotation of a sputtering target. By rotating the sputtering target, the surface of the sputtering target is moved with respect to the magnetic field.

[0031] The speed of rotation determines the time a particular fraction of the total surface area is within the magnetic field with the trapped plasma heating up the particular fraction. Fig. 6 shows a flow chart of a method of sputtering target gap width adjustment. By providing a predetermined speed of rotation (box 610), the temperature of the sputtering target is provided (box 510). Correspondingly, the gap width of two adjacent target segments is adjusted (box 520). For example, the gap width is adjusted to be within a desired gap width range during operation. If the gap during sputtering is not in the gap width range of 0.1 mm or below, the target rotation speed can be adjusted so that the target gap shall be within the desired gap width range. This speed of rotation is typically 20 rpm or below. More typically, the speed of rotation is from 0.5 rpm to 12 rpm, such as, for example, 10 rpm. For example, a heat load for the sputtering target can significantly increase at very low RPM.

[0032] In manufacturing segmented sputtering targets, adjacent target segments have a preset gap width, i.e. a manufactured gap width. The gap width may vary, for example, between used manufacturing methods, different target materials or between production batches. The pre-set gap width can be measured and may even be a property of the target upon sale of the target. The gap width varies when the sputtering targets are operated at a fixed temperature of operation. The gap width can be adjusted by providing a speed of rotation, wherein the speed of rotation provides a target temperature within a desired target temperature range. The target temperature to be within a desired target temperature range can be determined by embodiments of the method described herein.

100331 FIG. 4 shows a graph illustrating the effect of temperature changes on a target gap width. The graph 430 shows the gap width of two adjacent target segments in dependency of the target temperature. The scale of the temperature axis starts at the lowest temperature To. For example. To is a temperature at room temperature. Sputtering targets can be operated up to a maximal temperature T_max. Exceeding this value may lead to cracking of the target material, for example at a temperature above 200°C. At the desired target temperature range TD 450, the gap width is within a preferred gap width range 460. The target temperature during operation of the sputtering target is typically from 75°C to 200°C, particularly from 100°C to 175°C, for example up to about 165°C. The target temperature may be, for example, the temperature at the surface of the target. In graph 420 and 410, the gap width at the temperature T₀ is smaller compared to graph 430. Further, the slopes of the graphs are different. A graph starting at a large gap width at T₀ may for example have an increased slope compared to a graph starting at a smaller gap width at T₀. The slope may depend on the segment length and/or target material and/or other parameters associated to the adjacent target segments, or a bonding parameter. Exemplarily, graph 430 starts with a larger gap width at TO than graph 410 at To. Additionally, the slope of graph 430 is greater than the slope of graph 410, Consequently, there is an intercept of graph 430 and graph 410 at a temperature point at which both graphs have the same gap width. Said temperature point is preferably within the desired target temperature range 450. In Fig. 4 the different gap widths represented by graphs 410, 420, and 430 are at the desired target temperature range 450 within the preferred gap width range 460.

[0034] A sputtering target may have two or more gap widths. Fig 2 shows schematically a cross-sectional view of a section of a sputtering cathode 100. In this embodiment, the adjacent target segments 210, 220, of the sputtering target have different segment lengths. Segment lengths may not be consistent between manufacturers depending on their manufacturing capabilities. Different gap width control may be performed per segment length. For example, the segment length 222 is smaller than the segment length 212. In the method according to embodiments described herein, the gap width is adjusted by utilizing the thermal expansion of adjacent target segments. According to some embodiments, which can be combined with other embodiments described herein, at an initial temperature To. the gap width 240 can be smaller than the gap width 250. By providing a target temperature during operation within a desired target temperature range, the gap widths 240 and 250 can be adjusted. As the target segments have different segment lengths, there is a temperature point at which both gap widths 240, 250 have the same gap width. Preferably, the gap widths 240 and 250 may be equal or within an equal gap width range in a desired target temperature range.

[0035] In light of the above, a sputtering target for material deposition on the substrate in a vacuum deposition process can be provided. The sputtering target can include three or more target segments, wherein a first target segment of the three or more target segments has a first length and a second target segment of the three or more target segments has a second length, which is larger than the first lengths. A third target segment of the three or more target segments may have a length similar to the second length. According to some embodiments, which can be combined with other embodiments described herein, a first gap width between the first target segment and the second target segment can be smaller when compared to a second gap width between the second target segment and the third target segment, for example at room temperature or at another temperature lower than the temperature during operation. Due to the smaller expansion of the first target segment as compared to, for example, the second target segment and the third target segment, the first gap width will decrease with a smaller slope (see FIG. 4) as compared to the second gap width. A temperature increase during operation enables to provide for a similar first gap width as compared to the second gap width during operation. According to some embodiments, which can be combined with other embodiments described herein, the first gap width and the second gap width can be similar within the desired temperature range of methods according to embodiments described herein. Beneficially, this desire temperature range is the temperature range in which both gap widths, the first gap width and the second gap width, are larger than zero and equal or smaller than 0.1 mm.

[0036] According to different embodiments, which can be combined with other embodiments described herein, the sputtering cathode may further comprise a cooling element or an internal cooling passage for cooling the magnet assembly and/or for cooling the sputtering target. FIG. 7 shows a flow chart of another method to adjust the gap width, in which the target temperature is provided by adjusting a cooling element (box 710). Cooling may be performed by a fluid coolant, such as water. Adjusting the flow rate of the coolant or a temperature of the coolant can provide adjustment of a cooling, i.e. a cooling of the cooling element. [0037] Fig. 11 schematically shows a cross-sectional view of a sputtering cathode 100. The sputtering cathode comprises a cooling channel 1030 and a magnet assembly 1120. The cooling channel 1030 is typically connected to a cooling unit 1020. The cooling source may introduce the coolant into the cooling channel 1030 from one end of the sputtering target. The coolant flows in an opposite direction within the target, i.e. the backing tube, and cools the magnet assembly 1120 and the backing tube with a target, respectively. Heat can be transferred from the magnet assembly and/or backing tube to the coolant by pumping the coolant through the cooling channel 1030 and the backing tube, respectively, with the coolant having a flow rate. The flow rate may, for example, be 15 1/min to 25 l/mm. e.g. around 20 l/'min. By adjusting the flow rate and/or the temperature of the coolant, the amount of heat transferred away from the sputtering target to the coolant can be regulated. Exemplariiy, by reducing the flo rate during operation of the sputtering cathode, the temperature of the sputtering cathode having the sputtering target can be increased.

[0038] FIG. 9 shows schematically a deposition apparatus 900 in a vacuum chamber 920 according to embodiments described herein. This apparatus has a sputtering cathode 100 comprising a sputtering target 120. The sputtering target 120 may be rotatable around an axis 1 0. This rotation can be performed by a motor unit 940. To control the motor unit 940, a motor control unit 950 can be provided. The motor control unit 950 can act as or can be in communication with a control unit for the methods provided herein. The control unit can be provided for adjusting the temperature during operation to be within a desire temperature range. The control unit may control the motor control unit and the speed of rotation of the sputtering target. The motor control unit 950 is adapted to provide a predetermined speed of rotation of the sputtering target 120. As an example, the motor control unit 950 can set a speed of rotation of the sputtering target 120 as a value of 20 rpm or below. Reference numeral 960 illustratively shows the sputtered material to be deposited on a substrate. A substrate may be positioned on a substrate support 930. For example, the substrate may be provided in a carrier and the earner is provided on a substrate support within the vacuum chamber 920.

[0039] The gap width may also be determined during operation of the material deposition process. FIG. 8 shows a flow chart of a method of target gap width control. The gap width of a gap of two adjacent target segments is adjusted by providing a target temperature (box 5 0, box 520). At box 810, the gap width of the adjusted gap is determined. Determining the actual gap width during operation may comprise a measuring procedure. If the determined gap width is not within a preferred gap width range, a re-adjustment (box 820) of the gap width can be provided by providing a new target temperature to re-adjust the gap width. For example, a re-adjustment of the temperature may be provided by varying the rotation speed of the target and/or varying the flow rate or the temperature of the coolant.

[0040] In some embodiments, the methods described herein may be embodied in a computer readable medium The computer readable medium has instructions stored thereon that, when executed, cause apparatus for material deposition to perform a method material deposition on a substrate in a vacuum deposition process in accordance with any of the methods described herein.

[0041] FIG. 10 shows a deposition apparatus 1000 comprising a determining unit 1010. The determining unit 1010 may be a device for measuring the gap width, for example an optical measurement tool. The actual gap width during operation is detected by the determining unit and a signal containing the information of the gap width is passed to a control unit 1040. The control unit 1040 determines whether the gap width has to be adjusted. The control unit 1040 may control the speed of rotation of the motor unit 940. Additionally or aiteraatively, the control unit may control the cooling unit 1020, for example the flow rate of a coolant through the cooling channel 1030. The cooling element can be an adjustable cooling element. If the actual gap width is not in the desired gap width range, the control unit can adj st the target temperature by re-adjusting the motor unit 940 and/or the cooling unit 1020 during operation of the material deposition process.

10042] According to embodiments described herein, the method for material deposition on a substrate in a vacuum deposition process having a sputtering target can be conducted by computer programs, software, computer software products and the interrelated controllers, which can have a CPU, a memory, a user interface, and input and output devices being in communication with the corresponding components of the apparatus for material deposition on a substrate. 100431 While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method for material deposition on a substrate in a vacuum deposition process having a sputtering target, the method comprising: providing a target temperature of the sputtering target during operation to be within a desired target temperature range for adjusting a gap width of a gap of two adjacent target segments of the sputtering target.

2. The method of claim 1, whe ein the gap width is 0.1 mm or below.

3. The method of any one of claims 1 to 2, wherein the sputtering target is rotating.

4. The method of claim 3, wherein the target temperature is provided to be within the desired target temperature range by providing a predetermined speed of rotation of the sputtering target.

5. The method of claim 4, wherein the predetermined speed of rotation is 20 rpm or below, particularly 0.5 rpm to 12 rpm.

6. The method of any of claims 1 to 5, wherein the target temperature is provided by adjusting a cooling element, particularly wherein at least one of a temperature of a coolant of the cooling element is controlled and a flow rate of the coolant of the cooling element is controlled.

7. The method of any one of claims 1 to 6, wherein the desired target temperature range is determined by at least one value selected from a group comprising of: a gap width at room temperature, a thermal expansion coefficient of a material of the sputtering target, a length of a target segment of the adjacent target segments, and a bonding parameter,

8. The method of claim 7, wherein the bonding parameter is 0.5 to 0,8.

9. The method of any one of claims 1 to 8, wherein the target temperature during the operation of the sputtering target is from 75°C to 200°C, particularly from 100°C to 175°C.

10. The method of any of claims 1 to 9, wherein the sputtering target is a ube, the two adjacent target segments being coaxial to the tube provided along an axis of the tube.

1 1. The method of any of claims 1 to 10, further comprising: determining the gap width of the gap during operation; and adjusting the target temperature of the sputtering target during operation for adjusting the gap width.

12. The method of claim 11 , wherein the target temperature is adjusted by at least one of adjusting a speed of rotation and adjusting a cooling.

13. A sputtering target for material deposition on a substrate in a vacuum deposition process, the sputtering target comprises: three or more target segments, wherein a first target segment of the three or more target segments has a first segment length and a second target segment of the three or more target segments has a second segment length, wherein the second segment length is larger than the first segment length, and wherein a third target segment is provided having a third segment length larger than the first segment length; and a first gap width of a first gap between the first target segment and the second target segment and a second gap width of a second gap between the second target segment and a third target segment, wherein the first gap width is smaller than the second gap width, particularly at a first temperature lower than an operating temperature.

14. An apparatus for material deposition on a substrate in a vacuum deposition process, comprising: a vacuum chamber configured for housing one or more sputtering cathodes; a determining unit configured to determine a gap width of a gap of two adjacent target segments of the one or more sputtering cathodes during operation; and a control unit, wherein the control unit is configured to adjust a parameter adapted to change a temperature of a sputtering target.

15. The apparatus according to claim 14, further comprising at least one of a motor control unit and an adjustable cooling element.

16. The apparatus according to any of claims 14 to 15, wherein the apparatus is configured to perform a method for material deposition on a substrate in a vacuum deposition process having a sputtering target, the method as described in any of claims 1 to 12, and/or wherem the apparatus comprises at least a sputtering target according to claim 13.