Method of depositing a thin film transistor layer on a substrate and sputter deposition apparatus

Abstract

A method (480, 580) of depositing layers of a thin film transistor on a substrate using a sputter deposition source comprising at least one first electrode pair and at least one second electrode pair, the method comprising moving (482, 582) the substrate to a first vacuum chamber; depositing (484, 584) a first layer of the layers on the substrate by supplying a bipolar pulsed DC voltage to the at least one first electrode pair, wherein a first material of the first layer comprises a first metal oxide; moving (486, 586) the substrate from the first vacuum chamber to a second vacuum chamber without breaking vacuum; and depositing (488, 588) a second layer of the layers on the first layer by supplying a bipolar pulsed DC voltage to the at least one second electrode pair, wherein a second material of the second layer comprises a second metal oxide, the second material being different from the first material.

Description

Technical Field

[0001] This disclosure relates to the fabrication of semiconductor devices, particularly thin-film transistors. This disclosure relates to methods for depositing thin-film transistor layers on a substrate. This disclosure further relates to sputtering deposition equipment. Background Technology

[0002] Forming thin layers on substrates is a relevant issue, especially in the field of thin-film transistors (TFTs). One method for forming layers on substrates in the fabrication of TFTs is sputtering. During sputtering, atoms are ejected from a sputtering target by bombarding it with high-energy particles of plasma (e.g., excited ions of inert or reactive gases). The ejected atoms can then deposit on the substrate, thus forming a sputtered material layer on the substrate.

[0003] Known methods for depositing layers on a substrate for thin-film transistor fabrication use a static deposition process, wherein the substrate is positioned in front of a sputtering electrode of a deposition source. The deposition source may include at least one sputtering electrode, such as a sputtering cathode carrying a sputtering target, or a DC-driven array of sputtering electrodes for direct current (DC) sputtering.

[0004] The fabrication of thin-film transistors can involve the deposition of various layers, including, for example, a gate insulating layer, a channel layer for forming a channel between the source and drain, or a source-drain layer for forming the source and drain.

[0005] Providing thin-film transistors (TFTs) with consistent and stable performance, for applications such as displays, remains challenging. For example, the performance of TFTs can be unstable under stress, such as during the application of voltage to the TFT and / or at high temperatures. In particular, the performance of TFTs with high carrier mobility can be unstable. For instance, it may be difficult to apply TFTs with high carrier mobility in high-resolution movable panels.

[0006] Therefore, there has been a need for improved methods and sputtering deposition equipment for depositing thin-film transistor layers on substrates. More specifically, it would be desirable to provide thin-film transistors with high carrier mobility and high stability (especially under pressure). Summary of the Invention

[0007] Based on the foregoing, a method for depositing a thin-film transistor layer on a substrate, as well as a sputtering deposition apparatus, is provided according to the independent claims. Other aspects, advantages, and features of this disclosure will become apparent from the dependent claims, the specification, and the drawings.

[0008] One aspect of this disclosure relates to a method for depositing a layer of a thin-film transistor on a substrate using a sputtering deposition source, the sputtering deposition source including at least one first electrode pair and at least one second electrode pair. The method includes: moving the substrate to a first vacuum chamber; depositing a first layer of the layer on the substrate by supplying a bipolar pulsed DC voltage to at least one first electrode pair, wherein a first material of the first layer comprises a first metal oxide; moving the substrate from the first vacuum chamber to a second vacuum chamber without disrupting the vacuum; and depositing a second layer of the layer on the first layer by supplying a bipolar pulsed DC voltage to at least one second electrode pair, wherein a second material of the second layer comprises a second metal oxide, the second material being different from the first material.

[0009] On the other hand, sputtering deposition equipment is involved, particularly sputtering deposition equipment for depositing layers of thin-film transistors on a substrate. The sputtering deposition equipment includes a first vacuum chamber and a second vacuum chamber, arranged such that the substrate can be transferred between the first and second vacuum chambers without disrupting the vacuum. The sputtering deposition equipment includes a sputtering deposition source comprising at least one first electrode pair and at least one second electrode pair, wherein at least one first electrode pair is disposed in the first vacuum chamber and at least one second electrode pair is disposed in the second vacuum chamber. The sputtering deposition source further includes a power supply arrangement configured to supply a bipolar pulsed DC voltage to at least one first electrode pair and at least one second electrode pair. At least one first electrode pair includes a first target having a first target material, the first target material comprising a first metal oxide. At least one second electrode pair includes a second target having a second target material, the second target material comprising a second metal oxide and differing from the first target material.

[0010] The embodiments also relate to apparatus for performing the disclosed methods and include apparatus elements for performing various described method aspects. These method aspects may be performed via hardware components, a computer programmed with suitable software, by any combination of both, or in any other manner. Furthermore, embodiments according to this disclosure also relate to methods for operating the described apparatus. Methods for operating the described apparatus include method aspects for performing each function of the apparatus. Attached Figure Description

[0011] To gain a more detailed understanding of the features described above, reference can be made to embodiments that provide a more specific description of the disclosure. The accompanying drawings illustrate embodiments of the disclosure and are described below. Typical embodiments are depicted in the drawings and are described in detail below.

[0012] Figure 1 A schematic view of a sputtering deposition source according to some embodiments described herein;

[0013] Figure 2 A graph showing a bipolar pulsed DC voltage and a corresponding current that can be applied to an electrode pair in a sputtering deposition source according to an embodiment described herein;

[0014] Figure 3 A schematic drawing of an exemplary thin-film transistor is shown, the exemplary thin-film transistor comprising a layer deposited by a method or sputtering deposition source according to embodiments described herein;

[0015] Figure 4 A flowchart illustrating the method according to the implementation described herein; and

[0016] Figure 5 The flowchart illustrates a method according to another implementation described herein. Detailed Implementation

[0017] Reference will now be made in detail to various embodiments, with examples of the embodiments depicted in the figures. The examples are provided by way of illustration and are not intended to be limiting. For example, a feature that is illustrated or described as a part of one embodiment may be used on or in combination with any other embodiment to produce yet another embodiment. This disclosure is intended to include such modifications and variations.

[0018] In the following description of the accompanying drawings, the same reference numerals indicate the same or similar parts. Generally, only differences with respect to individual embodiments are described. Unless otherwise stated, the description of an element or aspect in one embodiment may also apply to the corresponding element or aspect in another embodiment.

[0019] The process of coating a substrate with a material described herein typically refers to a thin-film application. The terms "coating" and "deposition" are used synonymously. According to some embodiments, coating or deposition is performed by sputtering.

[0020] The sputtering deposition apparatus according to the embodiments described herein includes a first vacuum chamber and a second vacuum chamber. The first and second vacuum chambers are arranged such that a substrate can be transferred between the first and second vacuum chambers without disrupting the vacuum. Specifically, the sputtering deposition apparatus is configured such that the substrate can be moved from the first vacuum chamber to the second vacuum chamber without exposing it to a non-vacuum environment, particularly without exposing it to an environment with atmospheric pressure. The first vacuum chamber can be at least partially separated from the second vacuum chamber by a chamber wall of either the first or second vacuum chamber. The chamber wall may have slit openings. The slit openings can be configured such that a substrate, particularly the substrate and a substrate carrier holding the substrate, can be moved from the first vacuum chamber to the second vacuum chamber via the slit openings. In some embodiments, the slit openings may be closable or sealable by using a chamber valve.

[0021] According to an embodiment, a sputtering deposition apparatus includes a sputtering deposition source. The sputtering deposition source includes electrode pairs, particularly at least one first electrode pair and at least one second electrode pair. Each electrode in the electrode pair can be configured to provide target material to be deposited on a substrate. For example, each electrode can include a target made of the target material to be deposited on the substrate, such as a cylindrical target. Furthermore, each electrode can be configured to rotate together with the target material about a corresponding rotation axis. The electrodes of the electrode pair can be adjacent electrodes. For example, each electrode pair can include a first electrode and a second electrode, arranged at a distance of 50 cm or less, particularly 30 cm or less.

[0022] Sputtering can typically be performed using either diode sputtering or magnetron sputtering. Magnetron sputtering is particularly advantageous because the deposition rate can be very high. The magnet assembly can be housed within a rotatable electrode. By arranging the magnet assembly within the rotatable electrode, i.e., within the cylindrical target, free electrons above the target surface are forced to move within the magnetic field generated by the magnet assembly and cannot escape. The magnet assembly can be rotatable within the electrode. Magnetron sputtering can improve the deposition rate.

[0023] Figure 1 An exemplary embodiment of a sputtering deposition apparatus 100 is shown. The sputtering deposition apparatus 100 includes a first vacuum chamber 130 and a second vacuum chamber 140. A substrate 110 can be moved from the first vacuum chamber 130 to the second vacuum chamber 140 without disrupting the vacuum. In particular, the substrate 110 can be held by a substrate carrier. The substrate carrier holding the substrate 110 can move along a substrate transport track in a downstream direction 112. Figure 1As shown, a substrate 110 can be moved from a first vacuum chamber 130 to a second vacuum chamber 140 through a slit opening 114 in the chamber wall 116 in a downstream direction 112. The sputtering deposition apparatus 100 can be configured to continuously move the substrate 110 during deposition in the first vacuum chamber 130 and during deposition in the second vacuum chamber 140.

[0024] According to some embodiments, sputtering deposition equipment is configured for dynamic coating of a substrate, particularly in a first vacuum chamber and / or a second vacuum chamber. For example, the sputtering deposition equipment can be configured to continuously move the substrate along a substrate transport track during layer deposition. In another embodiment, the sputtering deposition equipment can be configured for static coating of a substrate. The substrate can enter the coating area prior to deposition, particularly within the coating area of ​​the first or second vacuum chamber. After entering the coating area, the sputtering deposition equipment can be configured to deposit a layer on the substrate. The substrate is held within the coating area during deposition. The sputtering deposition equipment can be configured to remove the substrate from the coating area after deposition. In particular, the vacuum chamber, such as the first or second vacuum chamber, can be sealable or closable relative to the environment or an adjacent vacuum chamber during deposition, for example, by using a chamber valve.

[0025] According to an embodiment, the sputtering deposition source of the sputtering deposition apparatus includes at least one first electrode pair disposed in a first vacuum chamber and at least one second electrode pair disposed in a second vacuum chamber. The at least one first electrode pair and / or at least one second electrode pair may include at least two or at least three electrode pairs, for example, exactly two or exactly three electrode pairs. The sputtering deposition source includes a power supply arrangement configured to supply a bipolar pulsed DC voltage to at least one first electrode pair and at least one second electrode pair. Figure 1 In the illustrated embodiment, the sputtering deposition apparatus 100 includes a sputtering deposition source having two first electrode pairs 132 arranged in a first vacuum chamber 130 and two second electrode pairs 142 arranged in a second vacuum chamber 140. A bipolar pulsed DC voltage is supplied to the first electrode pairs 132 and the second electrode pairs 142 by a power supply arrangement 120. The power supply arrangement 120 may include a DC power supply 124 and a pulse unit 122.

[0026] Figure 2This is a graph showing the variation of a bipolar pulsed DC voltage over time (t), which can be applied to an electrode pair in a sputtering deposition source according to embodiments described herein. A first graph 250 shows a first voltage U1 applied to a first electrode of the electrode pair, and a second graph 252 shows a second voltage U2 applied to a second electrode of the electrode pair. The second voltage U2 can be, for example, an inverted version of the first voltage U1. In an exemplary embodiment, a bipolar square wave or rectangular wave voltage is applied to the electrode pair. In practice, the positive and negative portions of the first and second voltages can only be approximately constant. Corresponding voltages can be applied synchronously to each of at least one first electrode pair and at least one second electrode pair.

[0027] In addition, Figure 2 The first figure 250 illustrates the time-varying current (1) flowing between the electrodes of the electrode pair during operation. The current may follow the shape of the applied voltage waveform. In particular, the frequency of the current may correspond to the frequency of the applied voltage.

[0028] According to an embodiment, at least one first electrode pair includes a first target having a first target material, the first target material comprising a first metal oxide. At least one second electrode pair includes a second target having a second target material, the second target material comprising a second metal oxide. Specifically, the second target material differs from the first target material. In an embodiment, at least one of the first and second target materials may be a semiconductor.

[0029] In embodiments, a sputtering deposition apparatus can be configured to deposit layers of thin-film transistors on a substrate. Specifically, the sputtering deposition apparatus can be configured to deposit layers according to embodiments of the methods described herein. Specifically, a first target material can be configured for a first layer of the deposited layer, wherein the first material of the first layer includes the material of the first target material, particularly a first metal oxide of the first target material. A second target material can be configured for a second layer of the deposited layer, wherein the second material of the second layer includes the material of the second target material, particularly a second metal oxide of the second target material. Specifically, the first and second target materials can be configured to deposit channel layers of the thin-film transistors. In some embodiments, the first and second target materials can at least substantially correspond to the first material of the first layer and the second material of the second layer, respectively, configured according to embodiments described herein.

[0030] In some embodiments, the first and second targets are rotating targets. For example... Figure 1As shown, the first electrode pair 132 includes a first target 134 and the second electrode pair includes a second target 144. Each of the first target 134 and the second target 144 is a rotating target. In particular, each of the first target 134 and the second target 144 is rotatable about a respective rotation axis A.

[0031] According to an embodiment, the sputtering deposition apparatus may include a substrate transport track along which the substrate can be transported. Specifically, the substrate can be moved along the substrate transport track to a first vacuum chamber and / or from the first vacuum chamber to a second vacuum chamber. During transport and / or during substrate processing, particularly during layer deposition, the substrate may be carried along the substrate transport track by a substrate carrier.

[0032] In some embodiments, the sputtering deposition apparatus may include at least one additional vacuum chamber having at least one additional electrode pair of a sputtering deposition source disposed within the sputtering deposition apparatus. The sputtering deposition apparatus, particularly the substrate transport track of the sputtering deposition apparatus, may be configured such that a substrate can be moved from a second vacuum chamber to at least one additional vacuum chamber without breaking the vacuum. The at least one additional electrode pair may include at least one additional target, wherein one of the at least one additional target comprises an additional target material. This additional target material may differ from the second target material, particularly from the first target material and from the second target material. In embodiments, this additional target material may have a different carrier mobility and / or a different carrier concentration relative to the second target material.

[0033] A method for depositing a thin-film transistor layer on a substrate is provided, according to embodiments that can be combined with other embodiments. A sputtering deposition source including at least one first electrode pair and at least one second electrode pair is used to deposit the thin-film transistor layer. In particular, the sputtering deposition source of the sputtering deposition apparatus according to the embodiments described herein can be used to deposit the thin-film transistor layer.

[0034] exist Figure 3 The image shows an exemplary drawing of a thin-film transistor 360. Fabrication of the thin-film transistor 360 may include a method of depositing layers of the thin-film transistor 360 according to embodiments described herein. The thin-film transistor 360 includes a support substrate 362. A gate electrode 364 is formed on the support substrate 362. A gate insulating layer 366 is deposited on the gate electrode 364. The gate insulating layer 366 includes an insulating material. For example, the gate insulating layer 366 may include silicon nitride (SiN). x ), silicon dioxide (SiO) x ), SiO x N (1-x) Materials with high dielectric constants, especially Alx O y ZrO x HfO x or GeO x , or any combination thereof.

[0035] A channel for a thin-film transistor 360 can be formed on the gate insulating layer 366. The channel may include a semiconductor material. The channel may be conductive, particularly in the on-state of the thin-film transistor, and non-conductive in the off-state. Specifically, the channel can be formed by depositing a first layer 368, particularly forming the front channel of the thin-film transistor 360, and by depositing a second layer 370, particularly forming the rear channel of the thin-film transistor 360. The first layer 368 may be formed of a first material and the second layer 370 may be formed of a second material, different from the first material. Each of the first and second materials may be a semiconductor material. For example, the first layer 368 may include partially oxidized indium gallium zinc oxide (IGZO) and the second layer 370 may include fully oxidized IGZO. According to another example, the first layer 368 may be formed of a composition of IGZO and a transparent conductive oxide (such as indium tin oxide (ITO), indium zinc oxide (IZO), or aluminum zinc oxide (AZO)), and the second layer 370 may, for example, include IGZO without the transparent conductive oxide.

[0036] The thin-film transistor 360 further includes a source / drain layer 374. The source / drain layer 374 may include a conductive material. The source / drain layer 374 may include or be composed of metal. For example, the source / drain layer 374 may include Mo, Ti, Ta, Cr, (Ta, Cr), Cu, Ag, Al, alloys thereof, or any combination thereof. The source / drain layer 374 may be structured, for example, by photolithography to form the source and drain of the thin-film transistor 360. The thin-film transistor 360 may be further processed by back-channel etching. In particular, the back-channel, such as the second layer 370, may be partially etched. The thin-film transistor 360 further includes a passivation layer 376 deposited on the source / drain layer 374.

[0037] Figure 3 For illustrative purposes, specific types of thin-film transistors are shown, specifically thin-film transistors with an anti-interlaced configuration. In some embodiments, the methods and apparatus disclosed herein can be configured for depositing layers of thin-film transistors with an anti-interlaced configuration, particularly for the fabrication of thin-film transistors including back-channel etching. Embodiments of the methods and apparatus described herein can also, or alternatively, be used for depositing layers of thin-film transistors that are not anti-interlaced.

[0038] Figure 4The flowchart illustrates method 480 for depositing a thin-film transistor layer according to an embodiment described herein. At 482, method 480 includes moving a substrate into a first vacuum chamber. In an embodiment, the substrate can be moved from a loading locking chamber or from a previously processed chamber into the first vacuum chamber.

[0039] In method 480 (484), the method includes depositing a first layer on a substrate by supplying a bipolar pulsed DC voltage to at least one first electrode pair, wherein a first material of the first layer comprises a first metal oxide. In some embodiments, the first layer forms a channel of a thin-film transistor, particularly a front channel of the thin-film transistor. In embodiments, the first layer is deposited on a gate insulating layer of the thin-film transistor. The gate insulating layer may comprise or be composed of an insulating material.

[0040] In step 486, the substrate is moved from the first vacuum chamber to the second vacuum chamber without disrupting the vacuum. Moving the substrate from the first vacuum chamber to the second vacuum chamber without disrupting the vacuum prevents atmospheric gases, especially atmospheric oxygen, from interacting with the first layer. Interactions with atmospheric gases can alter the material properties of the first layer and / or affect the operation of the thin-film transistor.

[0041] In method 480 (488), the method includes depositing a second layer on the first layer by supplying a bipolar pulsed DC voltage to at least one second electrode pair. The second material of the second layer comprises a second metal oxide, wherein the second material differs from the first material of the first layer. In some embodiments, the second layer forms the rear channel of the thin-film transistor. Specifically, the channel may be a dual-channel layer structure. In other embodiments, the second layer may form the intermediate channel layer of the thin-film transistor. The stability of the thin-film transistor under pressure can be improved by depositing more than one layer of different materials, particularly by depositing the first and second layers according to embodiments.

[0042] According to some embodiments, one of the first material and the second material includes a metal different from the other of the first material and the second material. Specifically, one of the first metal oxide and the second metal oxide may include a metal different from the other of the first metal oxide and the second metal oxide. In embodiments, particularly in embodiments of sputtering deposition apparatus, one of the first target material and the second target material includes a metal different from the other of the first target material and the second target material.

[0043] In some embodiments that can be combined with other embodiments, the first metal oxide of the first material or the first target material comprises a first stoichiometric element and the second metal oxide of the second material or the second target material comprises a second stoichiometric element. The second stoichiometry may differ from the first stoichiometry. In particular, the element may include at least two elements selected from the group consisting of indium, gallium, and zinc.

[0044] In an embodiment, the first metal oxide includes an element in a first oxidation state and the second metal oxide includes an element in a second oxidation state, which is different from the first oxidation state. For example, the first and second metal oxides may include at least one element selected from the group consisting of indium, gallium, zinc, tin, and aluminum, especially indium, gallium, and zinc. The first oxidation state of the at least one element in the first metal oxide may be different from the second oxidation state of the at least one element in the second metal oxide.

[0045] According to embodiments, the first material or the first target material has a different carrier mobility relative to the second material or the second target material. Specifically, the first metal oxide may have a different carrier mobility relative to the second metal oxide. The term "carrier mobility" as used herein refers to the mobility of charge carriers in a material, such as a semiconductor material. Specifically, carrier mobility may refer to the mobility of holes and / or electrons. For example, one of the first material and the second material may have a high carrier mobility. The other of the first material and the second material may have a low or moderate carrier mobility. A high carrier mobility may be greater than 30 cm⁻¹. 2 / Vs, especially above 50cm 2 Carrier mobility per unit volume (Vs). Low carrier mobility can be below 10 cm⁻¹. 2 / Vs, especially below 7cm 2 / Vs or less than 5cm 2 The carrier mobility is / Vs. A moderate carrier mobility can be a mobility in the range between high and low carrier mobility. In another embodiment, one of the first and second materials may have a high or moderate carrier mobility. The other of the first and second materials may have a low carrier mobility.

[0046] In an exemplary embodiment of the sputtering deposition apparatus, one of the first and second target materials may have a high carrier mobility. The other of the first and second target materials may have a low or medium carrier mobility. In another embodiment, one of the first and second target materials may have a high or medium carrier mobility. The other of the first and second target materials may have a low carrier mobility.

[0047] In some embodiments, the first material has a different carrier concentration relative to the second material. Specifically, the first metal oxide may have a different carrier concentration relative to the second metal oxide. In embodiments, the first target material may have a different carrier concentration relative to the second target material. The term "carrier concentration" as used herein refers to the concentration of charge carriers in a material, such as a semiconductor material. Specifically, carrier concentration may refer to the concentration of holes and / or electrons.

[0048] In some embodiments, the first material may have a higher carrier mobility and / or carrier concentration than the second material. In embodiments of sputtering deposition apparatus, the first target material may have a higher carrier mobility and / or carrier concentration than the second target material.

[0049] In another embodiment, the first material may have a lower carrier mobility and / or carrier concentration than the second material. In another embodiment of the sputtering deposition apparatus, the first target material may have a lower carrier mobility and / or carrier concentration than the second target material.

[0050] According to embodiments, at least one of the first and second metal oxides is indium gallium zinc oxide (IGZO), indium zinc tin oxide (IZTO), indium gallium zinc tin oxide (IGZTO), indium tin oxide (ITO), indium zinc oxide (IZO), or aluminum zinc oxide (AZO). In some embodiments, the first metal oxide may be one of IGZO, IZTO, IGZTO, ITO, IZO, or AZO, and the second metal oxide may be a different one selected from the group consisting of IGZO, IZTO, IGZTO, ITO, IZO, or AZO. For example, one of the first and second metal oxides may be a transparent conductive oxide, especially ITO, IZO, or AZO, and the other of the first and second metal oxides may be IGZO.

[0051] In some embodiments, the first metal oxide and the second metal oxide may comprise different compositions of one of IGZO, IZTO, IGZTO, ITO, IZO, or AZO. For example, one of the first metal oxide and the second metal oxide may comprise IGZO with a 1:1:1 (indium:gallium:zinc) composition, and the other of the first metal oxide and the second metal oxide may comprise different compositions of IGZO, such as 1:a:b (indium:gallium:zinc), where at least one of a and b is not equal to 1, for example, greater than or less than 1.

[0052] In exemplary embodiments, the first metal oxide may include indium, gallium, and zinc in a first oxidation state. The second metal oxide may include indium, gallium, and zinc in a second oxidation state, wherein the second oxidation state is higher or lower than the first oxidation state. In some embodiments, one of the first and second oxidation states may be a fully oxidized state. The combination of a first layer of a first material and a second layer of a second material with different carrier mobilities and / or different carrier concentrations can advantageously expand the process window of thin-film transistors with higher mobility and / or higher stability under pressure.

[0053] In some embodiments, at least one of the first material and the second material, particularly one of the first material and the second material, includes another metal oxide, particularly other than the first metal oxide and / or the second metal oxide. In embodiments, the other metal oxide included in the first material may be different from the first metal oxide. The other metal oxide included in the second material may be different from the second metal oxide. In some embodiments, the other metal oxide may be included in one of the first material and the second material. In other embodiments, the first material and the second material may include the other metal oxide. The first material and the second material may have different contents (e.g., mass fraction) of the other metal oxide.

[0054] According to embodiments, the other metal oxide may include aluminum oxide, especially Al2O3, and / or tin oxide, especially SnO2. Alternatively, the other metal oxide may include at least one transparent conductive oxide, especially indium tin oxide (ITO), indium zinc oxide (IZO), and / or aluminum zinc oxide (AZO). In particular, the first metal oxide and / or the second metal oxide may be IGZO, IZTO, IGZTO, ITO, IZO, or AZO. Including another metal oxide, such as a transparent conductive oxide, in the first or second material can increase at least one of the carrier concentration and carrier mobility of the respective material. In particular, the mobility of thin-film transistors can be improved. According to embodiments of the sputtering deposition apparatus, at least one of the first and second target materials, especially one of the first and second target materials, includes another metal oxide.

[0055] According to some embodiments, the first and second layers can be deposited as a layer stack, particularly a bilayer. In other embodiments, the first, second, and third layers can be deposited as a layer stack, particularly a trilayer. In embodiments, the layer stack can form a layered channel for a thin-film transistor.

[0056] According to the implementation, process gases may be provided during deposition. Process gases may include inert gases (such as argon) and / or reactive gases (such as oxygen, nitrogen, hydrogen and ammonia, ozone, active gases, or the like).

[0057] According to some embodiments, the substrate is continuously moved during the deposition of the first layer and during the deposition of the second layer (“dynamic coating”). Dynamic coating of the substrate, particularly the dynamic deposition of the first and second layers, can provide a consistent layer thickness, especially without target imprinting and / or process drift during the target lifetime. In another embodiment, the first and second layers can be deposited by static coating. The substrate can enter the coating area before deposition, after which the layers are deposited on the substrate. The substrate is held within the coating area during deposition and is removed from the coating area after deposition. In particular, a vacuum chamber, such as a first or second vacuum chamber, can be sealable or shut off relative to the environment or an adjacent vacuum chamber during deposition, for example, by using a chamber valve.

[0058] According to embodiments that can be combined with other embodiments described herein, the method may include moving a substrate to at least one other vacuum chamber for depositing at least one additional layer, such as a third layer, on the substrate. The substrate can be moved without breaking the vacuum. The at least one additional layer can be deposited using at least one other electrode pair. In particular, a bipolar pulsed DC voltage can be supplied to the at least one other electrode pair. The first layer, the second layer, and at least one other layer can form a layered channel of a thin-film transistor, such as a multilayer channel. The first layer can particularly form the front channel of the channel. In some embodiments, the at least one other layer may include another channel layer. The other channel layer may include another material. In particular, the other material may have at least one of a different carrier mobility and a different carrier concentration relative to the second material.

[0059] For example, Figure 5 An exemplary flowchart of method 580 according to an embodiment described herein is shown. Specifically, steps 582 to 588 of method 580 can be... Figure 4Methods 480 correspond to 482 to 488. At 590, method 580 includes moving the substrate from the second vacuum chamber to the third vacuum chamber without disrupting the vacuum. At 592, a third layer is deposited on the second layer using at least one third electrode pair. A bipolar pulsed DC voltage can be supplied to the third electrode pair. The third material of the third layer may include a third metal oxide, which is different from the second material. The third material may have at least one of different carrier mobilities and different carrier concentrations relative to the second material. In embodiments, the third metal oxide may be IGZO, IZTO, IGZTO, ITO, IZO, or AZO. The third material may further include another metal oxide, such as tin oxide, aluminum oxide, and / or at least one transparent conductive oxide, such as ITO, IZO, and / or AZO.

[0060] According to this disclosure, the term "substrate" as used herein includes both inflexible and flexible substrates. Inflexible substrates include, for example, glass substrates, wafers, transparent crystal sheets such as sapphire or the like, or glass plates. Flexible substrates include, for example, rolls or foils. According to some embodiments, the embodiments described herein can be used for display PVD, i.e., sputtering deposition on a large-area substrate for the display market. Deposition equipment can be configured to deposit layers on at least one of semiconductor, metal, and glass substrates. In particular, deposition equipment can be configured to manufacture at least one of semiconductor devices and display devices.

[0061] According to some embodiments, the corresponding substrate carrier, which can support one or more substrates, can have a diameter of at least 1m. 2 The dimensions can range from approximately 0.67m. 2 (0.73m x 0.92m, i.e., GEN4.5) to approximately 8m 2 More specifically from about 2m 2 up to about 9m 2 or even up to 12m 2 The substrate or carrier provided for the structures, apparatus (such as cathode assemblies) and methods according to the embodiments described herein can be a large-area substrate as described herein. For example, the large-area substrate or substrate carrier can be GEN 4.5, which has a thickness of approximately 0.67m. 2 The substrate (0.73m x 0.92m) corresponds to GEN 5, which is approximately 1.4m. 2 The substrate (1.1m x 1.3m) corresponds to GEN 7.5, which is approximately 4.29m. 2 The substrate (1.95m x 2.2m) corresponds to GEN 8.5, which is approximately 5.7m. 2The substrate (2.2m x 2.5m) corresponds to, or even GEN 10, which is approximately 8.7m. 2 The substrate (2.94m x 3.37m) is compatible. Similarly, even higher generations, such as GEN 11 and GEN 12, and their corresponding substrates can be implemented.

[0062] According to some embodiments that can be combined with other embodiments described herein, the substrate can be transported along a substrate transport track and / or during processing, particularly during deposition, in a substantially vertical orientation. As used herein, "substantially vertical" is understood, especially when referring to substrate orientation, to allow deviations from the vertical direction or orientation of ±20° or less, for example, ±10° or less. This deviation can be provided, for example, because substrate supports with some deviation from the vertical orientation can result in a more stable substrate position. Still, substrate orientation, for example, during transport along a substrate transport track and / or during substrate processing, is considered substantially vertical and is considered different from horizontal substrate orientation.

[0063] The bipolar pulsed DC voltage mentioned in this article is a voltage with alternating polarity (“bipolar”) applied to the electrodes of the electrode pair. Thus, the first electrode of the electrode pair alternately acts as the cathode and anode, and the second electrode of the electrode pair alternately acts as the anode and cathode.

[0064] The difference between bipolar pulsed DC sputtering and conventional AC sputtering (such as MF sputtering or RF sputtering) is that the voltage waveform is not sinusoidal. Instead, the voltage waveform can be temporarily substantially constant (direct current, "DC"). For example, the waveform of a bipolar pulsed DC voltage can be rectangular or square. In particular, the positive portion of the waveform can be temporarily substantially constant and / or the negative portion of the waveform can be temporarily substantially constant, especially unlike a sinusoidal voltage.

[0065] In some embodiments, the electrodes of the electrode pair may alternately serve as the anode and cathode. In particular, a single electrode that continuously serves as the anode may not be provided.

[0066] In some implementations, the frequency of the bipolar pulsed DC voltage can be at least 1 kHz, especially at least 10 kHz or at least 30 kHz, and / or at most 100 kHz, especially at most 80 kHz or at most 50 kHz.

[0067] In particular, sputtering with bipolar pulsed DC voltage allows for improved arc suppression, can have reduced process stability issues, and / or can provide higher layer consistency control, especially compared to conventional DC sputtering. Furthermore, the rectangular waveform voltage in DC bipolar sputtering can allow for reduced deposition rate loss, especially compared to conventional AC sinusoidal wave sputtering methods.

[0068] In some embodiments that can be combined with other embodiments described herein, the power supply arrangement can be configured such that each electrode in an electrode pair (in particular at least one first electrode pair and at least one second electrode pair) is supplied with a positive voltage, in particular a positive DC voltage, and a negative voltage, in particular a negative DC voltage. The electrodes of the electrode pair can alternately act as cathodes and anodes, in particular with respect to the other electrode of the same electrode pair.

[0069] In some embodiments, each of at least one first electrode pair and at least one second electrode pair may be connected to a DC power supply arranged in a power supply configuration via a pulse unit. The number of pulse units and / or the number of DC power supplies may correspond to the number of electrode pairs. The pulse unit may be configured to convert the DC voltage supplied by the DC power supply into a bipolar pulsed DC voltage.

[0070] At least one DC power supply, particularly each DC power supply, can be configured to provide a power of at least 1 kW, particularly at least 10 kW, and / or a maximum of 200 kW, particularly a maximum of 100 kW. Alternatively or additionally, at least one power supply, particularly each DC power supply, can be configured to provide a voltage of 100 V or greater and 1000 V or less. For example, at the output of the pulse unit, the voltage amplitude can periodically vary between a first value of +500 V and a second value of -500 V.

[0071] The term "vacuum" as used in this disclosure can be understood as a space substantially devoid of matter, such as a space in which all or most of the air or gas has been removed, except for the process gas used in deposition processes, such as sputter deposition. For example, the term "vacuum" can be understood in the sense of a technical vacuum having a vacuum pressure of less than, for example, 10 mbar. One or more vacuum pumps, such as turbopumps and / or cryogenic pumps, can be connected to a vacuum chamber, particularly to a first vacuum chamber and / or a second vacuum chamber, to provide a vacuum in the vacuum chamber for substrate processing such as layer deposition.

[0072] The embodiments described herein offer advantages in improving at least one of the stability and mobility of thin-film transistors (TFTs). Specifically, the process window for depositing layers for high-stability and high-mobility TFTs can be expanded. More specifically, the stability of TFTs under bias stress and / or thermal stress can be improved. Furthermore, the transistor threshold voltage of the TFT can be controlled close to 0V. The embodiments can provide the deposition of layers for TFTs with consistent and stable performance. In particular, deposition can be performed without target imprinting, without process drift, and / or without arcing.

[0073] Although the foregoing describes embodiments of the present disclosure, other and further embodiments of the present disclosure may be contemplated without departing from the basic scope of the present disclosure, and the scope of the present disclosure is defined by the appended claims.

Claims

1. A method (480, 580) for depositing a thin-film transistor layer on a substrate, the method using a sputtering deposition source comprising at least one first electrode pair and at least one second electrode pair, the method comprising: The substrate is moved (482, 582) to the first vacuum chamber, wherein a first vacuum pump is coupled to the first vacuum chamber; A first layer of the layer (484, 584) is deposited on the substrate by supplying a bipolar pulsed DC voltage to the at least one first electrode pair, wherein the first material of the first layer comprises a first metal oxide, and wherein the first layer forms the front channel of the thin film transistor. The substrate is moved from the first vacuum chamber (486, 586) to the second vacuum chamber without breaking the vacuum, wherein the second vacuum pump is coupled to the second vacuum chamber, and the first vacuum chamber and the second vacuum chamber share a chamber wall; and A second layer (488, 588) is deposited on the first layer by supplying a bipolar pulsed DC voltage to the at least one second electrode pair, wherein the second material of the second layer comprises a second metal oxide, the second material being different from the first material, and wherein the second layer forms the rear channel of the thin-film transistor; The movement of the substrate from the first vacuum chamber (486, 586) to the second vacuum chamber includes, during the deposition of the first layer and the second layer, the substrate being continuously moved from the first vacuum chamber to the second vacuum chamber through a slit opening in the chamber wall that separates the first vacuum chamber from the second vacuum chamber. and The first material has a lower carrier mobility and a lower carrier concentration than the second material, wherein the first material has a lower than 30 cm⁻¹ concentration. 2 The carrier mobility is / Vs, and the second material has a carrier mobility greater than 30 cm⁻¹. 2 / Vs carrier mobility.

2. The method of claim 1, wherein one of the first metal oxide and the second metal oxide comprises a metal different from the other of the first metal oxide and the second metal oxide.

3. The method of claim 1, wherein the first metal oxide comprises a first stoichiometric element, and wherein the second metal oxide comprises a second stoichiometric element, the second stoichiometry being different from the first stoichiometry.

4. The method of claim 3, wherein the elements comprise at least two elements selected from the group consisting of indium, gallium, and zinc.

5. The method of claim 1, wherein one of the first material and the second material further comprises another metal oxide, or wherein the first material and the second material have different contents of another metal oxide; and wherein the other metal oxide comprises at least one of tin oxide, aluminum oxide and transparent conductive oxide.

6. The method of claim 1, wherein one of the first material and the second material further comprises another metal oxide, or wherein the first material and the second material have different contents of another metal oxide; and wherein the other metal oxide comprises at least one of the following: tin oxide; aluminum oxide; and ITO, IZO or AZO.

7. The method of claim 1, wherein at least one of the first metal oxide and the second metal oxide is IGZO, IZTO, IGZTO, IZO, ITO or AZO.

8. The method of claim 1, wherein the first layer is deposited on the gate insulating layer.

9. The method of claim 1, wherein the method further comprises: The substrate is moved (590) from the second vacuum chamber to the third vacuum chamber without breaking the vacuum. and A third layer (592) is deposited on the second layer.

10. The method of claim 1, wherein the method further comprises: The substrate is moved (590) from the second vacuum chamber to the third vacuum chamber without breaking the vacuum. and A third layer (592) is deposited on the second layer using at least one third electrode pair.

11. A sputtering deposition apparatus (100), comprising: A first vacuum chamber (130) coupled to a first vacuum pump, a second vacuum chamber (140) coupled to a second vacuum pump, and a chamber wall that at least partially separates the first vacuum chamber and the second vacuum chamber, the first vacuum chamber, the second vacuum chamber and the chamber wall being arranged such that a substrate can be transferred between the first vacuum chamber (130) and the second vacuum chamber (140) through a slit opening in the chamber wall without breaking the vacuum; and Sputtering deposition source, said sputtering deposition source includes At least one first electrode pair (132) and at least one second electrode pair (142), wherein the at least one first electrode pair (132) is arranged in the first vacuum chamber (130), and wherein the at least one second electrode pair (142) is arranged in the second vacuum chamber (140); and A power supply arrangement (120) is configured such that the at least one first electrode pair (132) and the at least one second electrode pair (142) supply a bipolar pulse DC voltage; The at least one first electrode pair (132) includes a first target (134) having a first target material, the first target material including a first metal oxide, and wherein the first target material is configured to deposit a first layer of a thin film transistor to form a front channel of the thin film transistor; and The at least one second electrode pair (142) includes a second target (144) having a second target material, the second target material including a second metal oxide and the second target material being different from the first target material, and wherein the second target material is configured to deposit a second layer of the thin film transistor to form a rear channel of the thin film transistor; The first vacuum chamber, the second vacuum chamber, and the sputtering deposition source are arranged such that during the deposition of a first layer on the substrate using the at least one first electrode pair and during the deposition of a second layer on the substrate using the at least one second electrode pair, the substrate can be continuously moved from the first vacuum chamber to the second vacuum chamber through the slit opening, and transferred between the first vacuum chamber and the second vacuum chamber; and The first target material has a lower carrier mobility and a lower carrier concentration than the second target material, wherein the first target material has a concentration of less than 30 cm⁻¹. 2 The carrier mobility is / Vs, and the second target material has a carrier mobility greater than 30 cm⁻¹. 2 / Vs carrier mobility.

12. The sputtering deposition apparatus (100) of claim 11, wherein the first target (134) and the second target (144) are rotating targets.

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