Increasing adhesion through interface bonding layer
By introducing an interfacial bonding layer (IBL) between the glass substrate and the metal layer, and using metal oxides, nitrides and oxynitrides to form a stable interface, the problem of mechanical stress embrittlement and hydrolytic degradation of traditional FMM in large-size AMOLED panels is solved, achieving high adhesion and long-term stability, which is suitable for high-resolution OLED manufacturing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN MAXVISION TECHNOLOGY CO LTD
- Filing Date
- 2025-11-11
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional FMMs are prone to embrittlement due to mechanical stress in large-size AMOLED panels, leading to mask misalignment and deformation. Segmented mask design causes alignment difficulties, and the adhesion between the glass substrate and the metal layer is insufficient, resulting in severe hydrolytic degradation, which affects the stability and lifespan of the manufacturing process.
An interfacial bonding layer (IBL) is introduced, which uses metal oxides, nitrides and oxynitrides to form covalent or ionic bonds with the glass substrate and the upper metal layer, forming a stable interface, eliminating Si-OH groups, enhancing adhesion and resisting hydrolytic degradation.
It improves the adhesion and stability between the glass substrate and the metal layer, prevents delamination, ensures alignment accuracy and reliability for multiple uses in the manufacturing process of high-resolution OLEDs, and is suitable for microOLED and large-size AMOLED displays.
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Figure CN122013104A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic light-emitting diode (OLED) display manufacturing, focusing on enhancing the adhesion, stability, and durability of masking technology, solving the bonding challenges between the substrate and the metal layer, and ensuring reliable performance in the precise organic material deposition required for high-resolution displays. Background Technology
[0002] Traditional fine metal masks (FMMs) based on Invar alloys are widely used for precise RGB material deposition, but they face limitations when applied to larger AMOLED panels. Invar alloys are chosen for their low coefficient of thermal expansion (CTE); however, they are prone to embrittlement under mechanical stress, which can lead to mask misalignment and deformation, especially in larger display panels. Furthermore, segmented mask designs for larger substrates can cause alignment difficulties and reduce production efficiency.
[0003] In microOLED manufacturing, the demand for ultra-fine pixel patterns (over 2000 ppi) challenges the capabilities of traditional f-mode masks, even when using advanced materials such as silicon nitride (FSM). However, silicon nitride-based masks are generally unsuitable for mass production due to their susceptibility to failure under mechanical stress.
[0004] Patent application number 113209991, filed on September 12, 2024, is based on the development of FMM and OMM technologies in the manufacturing of AMOLED and microOLED displays. These prior technologies aim to address challenges such as scalability, mechanical stability, and accuracy, thereby improving the deposition of high-resolution organic materials for various display sizes.
[0005] Despite these advances, several key issues remain unresolved, particularly in GS-FMM and GS-OMM structures that combine glass substrates with metal layers. Major challenges include insufficient interlayer adhesion, hydrolytic degradation, and long-term stability. These issues can affect mask alignment during manufacturing and shorten operational lifespan across multiple uses.
[0006] In GS-FMM and GS-OMM structures, poor adhesion between the glass substrate and the metal layer is a significant challenge. The glass substrate typically has Si–OH (silanol) groups on its surface, which readily absorb moisture, leading to hydrolytic degradation and a gradual weakening of adhesion. This degradation is accelerated by cleaning cycles and environmental exposure, resulting in delamination and interface failure.
[0007] A robust solution requires chemical and mechanical stability at the interface to resist environmental degradation and maintain adhesion over repeated use. However, existing methods have not fully met the requirements for hydrolytic adhesion resistance at glass-metal interfaces, indicating room for improvement in adhesion technology during OLED mask manufacturing. Summary of the Invention
[0008] This invention introduces an interfacial bonding layer (IBL) to improve the adhesion between the glass substrate and the metal layer in glass-substrate fine metal mask (GS-FMM) and metal-organic mask (GS-OMM) processes during OLED manufacturing. Unlike traditional methods that rely on direct adhesion or common metals (such as titanium, chromium, or nickel), this invention emphasizes the use of metal oxides, nitrides, and oxynitrides as IBLs. These IBLs can form covalent or ionic bonds with the glass substrate and the upper metal layer, thereby establishing a strong and hydrolytically resistant stable interface.
[0009] The selected IBL materials, such as Al2O3, Si3N4, SiON, and HfO2, not only possess chemical stability but also exhibit a coefficient of thermal expansion (CTE) below 15 ppm / °C, thereby reducing potential thermal stress. This helps prevent problems such as delamination or cracking during deposition while maintaining strong adhesion.
[0010] The core function of IBL (Insulated Glass Layer) is as a passivating coating, covering the Si–OH groups on the glass surface that are susceptible to degradation. This degradation typically occurs due to exposure to air, moisture, and repeated cleaning cycles, weakening the interface over time. By removing these reactive groups, IBL forms a stable and hydrolysis-resistant surface, thereby promoting reliable adhesion to the overlying metal layers. In critical steps such as back-side HF etching, the IBL, base metal layer (BML), and aperture metal layer (AML) are protected by a thick photoresist (PR) or UV film to ensure they are unaffected by the process.
[0011] The application of IBL in this invention significantly improves the long-term stability and performance of GS-FMM and GS-OMM structures. Enhanced adhesion prevents delamination during prolonged exposure to moisture or cleaning processes, and maintains alignment accuracy in high-resolution OLED manufacturing. This ensures the mask can withstand multiple deposition and cleaning cycles without performance degradation, making it suitable for microOLED and large-size AMOLED displays.
[0012] This invention provides a comprehensive solution by addressing key issues in OLED mask manufacturing, such as adhesion stability, chemical durability, and mechanical properties. This solution is applicable to various display sizes, ensuring consistent reliability and high yield throughout the manufacturing process. Attached Figure Description
[0013] Figure 1 This diagram illustrates the structure of a glass-substrate fine metal mask (GS-FMM) for micro-OLED applications. Figure 1 A is the top view of GS-FMM. Figure 1 B is a cross-sectional view, showing its layered structure and the parts exposed to the environment.
[0014] Figure 2 A summary table of key interfacial bonding layers (IBLs) is provided, including Al2O3, Si3N4, SiON, and HfO2. Each IBL possesses unique properties, such as chemical stability, Si–OH passivation effect, and adhesion characteristics, making them suitable for improving durability and performance in OLED manufacturing.
[0015] Figure 3 A cross-sectional view of a GS-FMM with a single interface bonding layer (IBL) applied on a glass substrate is shown. In this example, Al2O3 is used as the IBL, and a base metal layer (BML) and an open-cell metal layer (AML) are deposited on it.
[0016] Figure 4 A cross-sectional view of a GS-FMM with a multilayer interface bonding layer (IBL) applied on a glass substrate is shown. In this structure, Al2O3 and Si3N4 layers are deposited sequentially to provide enhanced adhesion and stability, and a base metal layer (BML) and an open-hole metal layer (AML) are stacked on top of them.
[0017] Figure 5 A GS-FMM structure with an adhesion-promoting layer (APL) added between the interface bonding layer (IBL) and the metal layer is described. This configuration includes Al2O3 as the IBL, followed by the addition of an adhesion-promoting layer (selected from nickel, chromium, or titanium), a base metal layer (BML), and an open-cell metal layer (AML).
[0018] Figure 6 A simplified GS-FMM structure is illustrated, which contains only one metal layer, namely an open-hole metal layer (AML) deposited directly on the interface bonding layer (IBL). This configuration is suitable for micro-OLED applications with a low requirement for the number of metal layers. Detailed Implementation
[0019] Figure 1 The structural configuration of a glass substrate fine metal mask (GS-FMM) designed for micro OLED applications is described. Figure 1 A is a plan view of GS-FMM. Figure 1B is a cross-sectional view, showing in detail its layered structure and the portions exposed to the environment. In the cross-sectional view, the substrate metal layer (BML) 13 and the aperture metal layer (AML) 14 are directly exposed to the external environment. The glass substrate 11 forms the structural support for the mask, providing dimensional stability, while the substrate metal layer (BML) 13 and the aperture metal layer (AML) 14 perform the functions required for precise material deposition. The substrate metal layer (BML) 13 is deposited directly on the glass substrate 11, serving as the adhesion interface and the electrode layer for forming the aperture metal layer (AML) 14 during the electroforming (EF) process. The aperture metal layer (AML) 14 is used to define the precise aperture required for OLED manufacturing, ensuring the accuracy and quality of the high-resolution display process.
[0020] Both the base metal layer (BML) 13 and the aperture metal layer (AML) 14 are exposed to environmental stresses such as moisture, oxidation, and repeated cleaning cycles. This exposure may affect the adhesion of the interface between the glass substrate 11 and the base metal layer (BML) 13, as well as the interface between the base metal layer (BML) 13 and the aperture metal layer (AML) 14, leading to delamination or mask misalignment during manufacturing. While thermal cycling introduces stress, hydrolytic degradation due to moisture absorption poses a more significant threat, especially at the interface between the glass substrate 11 and the base metal layer (BML) 13.
[0021] The main challenge lies at the interface between the glass substrate 11 and the base metal layer (BML) 13, where the Si–OH (silanol) groups on the surface of the glass substrate 11 are susceptible to moisture absorption, weakening adhesion over time. Conventional adhesion-enhancing layers (APL) 17 (such as titanium, chromium, or nickel) are commonly used to improve adhesion, but they are still susceptible to hydrolytic degradation, potentially leading to delamination under harsh cleaning conditions.
[0022] To address these adhesion challenges, a more reliable solution is needed to stabilize the glass surface 11 and prevent hydrolytic degradation. This invention introduces interfacial bonding layers (IBLs) 15 and 16 between the glass substrate 11 and the base metal layer (BML) 13 to eliminate Si–OH groups and create a stable and hydrolysis-resistant interface. Specific details of the IBLs will be further described in subsequent sections.
[0023] One of the most effective interfacial bonding layers (IBL) is alumina (Al₂O₃) 15, used to enhance the adhesion between glass 11 and the metal. When deposited on the glass surface 11, alumina (Al₂O₃) 15 acts as a passivation layer, neutralizing reactive Si–OH groups that weaken adhesion over time. The passivation process involves a series of chemical reactions between alumina (Al₂O₃) 15 and hydroxyl groups on the glass surface, forming a stable, hydrolysis-resistant interface that firmly bonds to the base metal layer (BML) 13.
[0024] The surface of the glass substrate 11 naturally contains highly reactive and hygroscopic Si–OH (silanol) groups. When alumina (Al2O3) 15 is deposited using atomic layer deposition (ALD) or chemical vapor deposition (CVD) processes, it reacts directly with these silanol groups through a series of hydrolysis and condensation reactions: Initial hydrolysis: In the first stage, the hydroxyl groups on the glass surface react with the aluminum precursor (such as trimethylaluminum, TMA) introduced during the deposition process, replacing the Si–OH groups with the intermediate Si–O–Al groups and releasing methane (CH4) or other byproducts, depending on the chemical properties of the precursor.
[0025] Reaction formula: Si–OH + Al(CH3)3 → Si–O–Al + 3CH4.
[0026] Condensation reaction: In the subsequent stage, the adjacent Si–O–Al groups react further with the Al–OH groups formed in the hydrolysis step, releasing water molecules and establishing a stable Al–O–Si bond network.
[0027] Reaction formula: Si–O–Al + Al–OH → Si–O–Al–O–Al + H2O.
[0028] The Al–O–Si bond forms a chemically stable interface, eliminating reactive Si–OH groups, thus giving the surface hydrolysis resistance and moisture-proof properties.
[0029] Once the alumina (Al2O3) layer 15 covers the surface of the glass substrate 11, the passivated surface is ready for metal layer deposition. Strong Al–O–Si bonds ensure that the base metal layer (BML) 13 deposited thereon adheres reliably to the glass substrate 11. This adhesion mechanism provides the mask with the necessary adhesion strength under repeated cleaning cycles and mechanical stress, thereby preventing delamination or degradation.
[0030] Silicon nitride (Si3N4)16 is another effective interfacial bonding layer (IBL) that promotes adhesion between the glass substrate 11 and the base metal layer (BML) 13. Similar to aluminum oxide (Al2O3)15, silicon nitride (Si3N4)16 acts as a passivation layer, eliminating reactive Si–OH groups on the glass surface and thus preventing hydrolytic degradation. Silicon nitride (Si3N4)16 also forms a chemically stable interface, supporting the deposition of metal layers with strong and durable adhesion.
[0031] The deposition of silicon nitride (Si3N4)16 is typically performed using chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD). In this process, silicon-based precursors such as silane (SiH4) or tetraethoxysilane (TEOS) react with a nitrogen source such as ammonia (NH3) to form a thin silicon nitride (Si3N4) film. After film deposition, two key reaction steps occur with the Si–OH groups on the surface of the glass substrate 11: Silicon-nitrogen and Si–OH interaction: During deposition, the Si–N bonds from the silicon nitride (Si3N4) layer 16 interact with the hydroxyl groups on the surface of the glass substrate 11. The hydroxyl groups are replaced by Si–N–Si bridges, releasing water as a byproduct.
[0032] Reaction formula: Si–OH + NH3 + SiH4 → Si–N–Si + H2O + other byproducts.
[0033] Condensation and Network Formation: As the silicon nitride (Si3N4) layer 16 grows, additional Si–N–Si bonds are formed, creating a dense cross-linked network that completely covers the surface of the glass substrate 11. This network effectively seals reactive Si–OH groups, preventing moisture absorption and ensuring long-term hydrolysis resistance.
[0034] Once the silicon nitride (Si3N4) layer 16 is formed, the passivated surface provides a chemically stable platform for the subsequent deposition of the base metal layer (BML) 13. The Si–N bonds promote strong adhesion, ensuring the metal layer is firmly attached to the glass substrate 11. Furthermore, the silicon nitride (Si3N4) 16 exhibits high chemical resistance to cleaning agents and environmental exposure, contributing to the durability of glass substrate fine metal masks (GS-FMM) or glass substrate open metal masks (GS-OMM) during repeated cleaning and use cycles.
[0035] Silicon oxynitride (SiON) is another candidate material for interfacial bonding layers (IBLs), combining the properties of silicon dioxide (SiO2) and silicon nitride (Si3N4). SiON provides a balance of chemical stability, moisture resistance, and adhesion strength between the glass substrate 11 and the base metal layer (BML) 13. Its structure contains both Si–O and Si–N bonds, making it particularly suitable for passivating glass surfaces and ensuring long-term durability.
[0036] Silicon oxynitride (SiON) is typically deposited via chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD), using silicon and nitrogen sources such as silane (SiH4) or tetraethoxysilane (TEOS), with the addition of ammonia (NH3) and oxygen. The resulting SiON film contains both oxygen and nitrogen atoms, which can effectively interact with the Si–OH groups on the surface of the glass substrate 11. The process is as follows: Si–OH group reaction: In the initial stage of deposition, nitrogen atoms from the SiON layer react with Si–OH groups to form Si–N–Si bridges. These bridges replace hydroxyl groups and release water, thereby reducing the surface's sensitivity to moisture.
[0037] Reaction formula: Si–OH + NH3 → Si–N–Si + H2O.
[0038] Formation of mixed Si–O and Si–N bonds: As deposition continues, the silicon oxynitride (SiON) layer gradually forms a mixed network of Si–O and Si–N bonds, further sealing the surface and preventing moisture penetration. The coexistence of oxygen and nitrogen enhances chemical resistance and provides strong anchoring points, facilitating the deposition of subsequent metal layers.
[0039] Silicon oxynitride (SiON) offers greater flexibility in terms of chemical bonding and environmental resistance. Si–N bonds facilitate strong adhesion to the metal layer, while Si–O bonds ensure good compatibility with the glass substrate. This dual bonding characteristic makes the SiON layer a stable passivation interface, resistant to hydrolysis and ensuring long-term adhesion.
[0040] After the surface of the glass substrate 11 is passivated by the silicon oxynitride (SiON) layer, the base metal layer (BML) 13 can be reliably deposited on it, forming strong covalent or ionic bonds with the metal layer. Furthermore, silicon oxynitride (SiON) exhibits good chemical resistance to cleaning solutions, making it suitable for multiple deposition and cleaning cycles. The combined properties of silicon oxynitride (SiON)—including chemical resistance, adhesion strength, and moisture resistance—make it an ideal interfacial bonding layer (IBL) material for glass substrate fine metal mask (GS-FMM) and glass substrate open metal mask (GS-OMM) applications.
[0041] Hafnium oxide (HfO2) is another promising interfacial bonding layer (IBL) material used to enhance the adhesion between the glass substrate 11 and the base metal layer (BML) 13. Hafnium oxide (HfO2) possesses high chemical stability, excellent moisture resistance, and strong metal-oxide bonding properties. After deposition on the surface of the glass substrate 11, it effectively passivates reactive Si–OH groups, ensuring a durable and hydrolysis-resistant interface.
[0042] Hafnium oxide (HfO2) can be deposited on the surface of glass substrate 11 by atomic layer deposition (ALD) or chemical vapor deposition (CVD) to form a thin and uniform capping layer. The passivation process is as follows: Si–OH group reaction: In the initial stage of deposition, the hafnium precursor (such as HfCl4) reacts with the hydroxyl groups on the surface of glass substrate 11 to form Si–O–Hf bonds and release HCl or other byproducts. This reaction replaces the Si–OH groups, forming a stable interface.
[0043] Reaction formula: Si–OH + HfCl4 → Si–O–Hf + HCl.
[0044] Condensation and Network Formation: As deposition continues, adjacent Si–O–Hf bonds undergo further condensation reactions to form a dense HfO2 network, completely covering the surface of the glass substrate 11 and eliminating residual hydroxyl groups. This network provides excellent resistance to hydrolysis and prevents moisture from penetrating the interface.
[0045] Hafnium oxide (HfO2) exhibits excellent chemical resistance to highly corrosive cleaning agents, including hydrofluoric acid-based cleaners, and maintains stable performance during repeated ultrasonic cleaning cycles. Its high dielectric constant and strong metal-oxide ionic bonds ensure that the substrate metal layer (BML)13 remains firmly attached even under mechanical or environmental stress.
[0046] Hafnium oxide (HfO2) has a coefficient of thermal expansion of approximately 5–6 ppm / °C, which is compatible with glass substrate 11 (approximately 3 ppm / °C), thereby reducing the risk of thermal stress during OLED manufacturing. Thanks to its combined advantages in thermal expansion compatibility, chemical stability, and bonding strength, hafnium oxide (HfO2) ensures the stability of glass substrate fine metal masks (GS-FMM) or glass substrate open metal masks (GS-OMM) during multiple deposition and cleaning cycles.
[0047] In summary, hafnium oxide (HfO2) serves as an ideal interfacial bonding layer (IBL), providing a stable metal adhesion interface by eliminating Si–OH groups and exhibiting excellent chemical resistance under environmental degradation conditions. These properties make it particularly suitable for high-precision OLED manufacturing, ensuring the reliable adhesion and durability required for long-term performance.
[0048] Figure 2This paper presents an overview of four interfacial bonding layers (IBLs)—alumina (Al₂O₃)₁₅, silicon nitride (Si₃N₄)₁₆, silicon oxynitride (SiON), and hafnium oxide (HfO₂)—and illustrates how they promote adhesion between the glass substrate 11 and the metal layer by eliminating Si–OH groups. Each IBL establishes a stable chemical bond at the interface of the glass substrate 11, thereby enhancing the hydrolysis resistance and mechanical durability of OLED mask applications.
[0049] Alumina (Al₂O₃)₁₅ removes Si–OH groups through hydrolysis and condensation reactions, forming strong Al–O–Si bonds to replace reactive hydroxyl groups. Typical precursors include trimethylaluminum (TMA) and water, but other precursors such as aluminum chloride (AlCl₃) or aluminum isopropoxy can also be used, providing flexibility for the deposition process. The formation method is not limited to specific precursors or atomic layer deposition (ALD) / chemical vapor deposition (CVD) processes and can be optimized according to manufacturing requirements. Once the alumina (Al₂O₃) layer is established, it forms robust Al–O–Metal bonds with the substrate metal layer (BML)₁₃, resulting in strong adhesion. Its coefficient of thermal expansion is approximately 8 ppm / °C, exhibiting good compatibility with the glass substrate 11.
[0050] Silicon nitride (Si3N4)16 forms Si–N–Si bridges through the reaction of ammonia (NH3) with precursors such as silane (SiH4), thereby removing Si–OH groups and generating a dense cross-linked network to ensure high chemical stability. Silicon nitride (Si3N4)16 effectively bonds to the metal layer through Si–N–Metal bonds, forming a reliable interface. Its coefficient of thermal expansion is approximately 3 ppm / °C, which is highly compatible with the glass substrate 11, reducing thermal stress during OLED manufacturing.
[0051] Silicon oxynitride (SiON) combines the advantages of silicon nitride (Si3N4) and silicon dioxide (SiO2), forming a hybrid network structure composed of Si–O and Si–N bonds. This structure provides enhanced chemical resistance and greater bonding flexibility with glass and metal layers. The precursor combination for SiON typically includes tetraethoxysilane (TEOS), ammonia (NH3), and oxygen (O2). Its versatility makes it suitable for a variety of OLED applications, and its coefficient of thermal expansion (CTE) of approximately 3–7 ppm / °C provides moderate thermal stability.
[0052] Hafnium oxide (HfO2) passivates the surface of the glass substrate 11 by forming Si–O–Hf bonds that are highly resistant to hydrolysis. Its deposition can be achieved using precursors such as hafnium tetrachloride (HfCl4) or hafnium isopropoxide. Hafnium oxide (HfO2) forms Hf–O–Metal ionic bonds with the metal layer, ensuring durable adhesion. Its coefficient of thermal expansion is approximately 5–6 ppm / °C, which matches well with the glass substrate 11, effectively preventing thermal stress during OLED manufacturing.
[0053] Interfacial Bonding Layer (IBL) Summary: Alumina (Al₂O₃)¹⁵, silicon nitride (Si₃N₄)¹⁶, silicon oxynitride (SiON), and hafnium oxide (HfO₂) each possess unique advantages in chemical bonding, thermal stability, and moisture resistance. Appropriate IBL materials can be flexibly selected based on manufacturing requirements, such as chemical resistance, coefficient of thermal expansion (CTE) matching, and bond strength. Furthermore, the use of different deposition processes and precursors further enhances flexibility, enabling manufacturers to adapt to specific needs. By eliminating Si–OH groups, these IBLs ensure strong adhesion to the glass substrate¹⁶ interface and contribute to maintaining the structural stability of the mask during repeated deposition, cleaning, and environmental exposure cycles.
[0054] In addition to the main interfacial bonding layer (IBL) candidates (such as alumina (Al2O3)15, silicon nitride (Si3N4)16, silicon oxynitride (SiON), and hafnium oxide (HfO2)), other metal oxides, nitrides, or oxides of nitride can be selected as IBLs depending on specific manufacturing requirements. These materials share the same goal: passivating the surface of the glass substrate 11, enhancing adhesion to the metal layer, and minimizing thermal stress. Several other candidate materials are listed below: Zirconia (ZrO2): provides high chemical stability and can form Si–O–Zr bonds with the surface of the glass substrate 11 to promote adhesion. Zirconia (ZrO2) also exhibits resistance to corrosion and harsh cleaning cycles, making it a preferred material in harsh environments.
[0055] Titanium oxide (TiO2): Although titanium oxide (TiO2) is not usually the first choice for passivating Si–OH groups, it has excellent metal adhesion and chemical durability, making it suitable for multilayer structures.
[0056] Aluminum nitride (AlN): Known for its high thermal conductivity, aluminum nitride (AlN) provides good metal bonding performance and has a certain ability to neutralize the hydroxyl groups on the surface of the glass substrate.
[0057] Magnesium oxide (MgO): Although less commonly used, magnesium oxide (MgO) offers good chemical stability and has the potential to serve as a moisture-proof passivation layer.
[0058] These additional interfacial bonding layer (IBL) candidates expand the range of available materials to meet the needs of different process and environmental conditions. For example, zirconium oxide (ZrO2) performs well in highly corrosive environments, while aluminum nitride (AlN) is more ideal for applications requiring high thermal conductivity. The selection of the interfacial bonding layer (IBL) can be flexibly tailored to environmental exposure, cleanliness requirements, and thermal stability requirements.
[0059] Regardless of the material chosen, the deposition process can be optimized according to its specific characteristics. Atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), and other vapor deposition methods can all achieve thin, uniform coatings with high process flexibility. Precursors for different materials can be selected based on manufacturing requirements; for example, zirconium oxide (ZrO2) can be deposited using zirconium chloride (ZrCl4) or zirconium tetraethoxylate [Zr(OCH2CH3)4], while aluminum nitride (AlN) is suitable for deposition using aluminum chloride (AlCl3) and ammonia (NH3). This flexibility ensures optimal interfacial bonding layer (IBL) composition and structure, thereby enhancing adhesion and ensuring long-term stability.
[0060] Immediately following plasma cleaning, physical vapor deposition (PVD) of the metal layer is another potential approach to improve adhesion between the glass substrate 11 and the metal layer. Plasma cleaning removes surface contaminants and breaks Si–OH groups, exposing active Si sites on the glass surface. When the metal layer is subsequently deposited immediately via PVD, the new active surface can bond more effectively to the metal layer. However, while plasma cleaning combined with PVD deposition can enhance adhesion, it is not an ideal solution. The process may leave residual hydroxyl groups, and its adhesion strength and durability are generally not as good as those achieved using interfacial bonding layers (IBLs) such as alumina (Al2O3) 15 or silicon nitride (Si3N4) 16. Furthermore, factors such as ambient humidity can still cause interface degradation over time.
[0061] Figure 3A cross-sectional schematic diagram of a glass-substrate fine metal mask (GS-FMM) is shown, in which an interfacial bonding layer (IBL) is deposited on a glass substrate 11. In this example, alumina (Al2O3) 15 is used as the IBL; however, any candidate IBL material (including alumina (Al2O3) 15, silicon nitride (Si3N4) 16, silicon oxynitride (SiON), hafnium oxide (HfO2), zirconium oxide (ZrO2), titanium oxide (TiO2), magnesium oxide (MgO), or aluminum nitride (AlN)) can be used depending on specific manufacturing requirements. The thickness of the IBL ranges from 1 to 200 nm, preferably about 100 nm, to ensure optimal adhesion and maintain structural integrity. A base metal layer (BML) 13 with a coefficient of thermal expansion (CTE) of less than 20 ppm / °C is deposited on the IBL, followed by the deposition of another open-pore metal layer (AML) 14 with the same low CTE, forming a functional mask structure. The aperture metal layer (AML) 14 can be made of Invar alloy or other low CTE metals to provide dimensional stability during material deposition. This structure illustrates how the interface bonding layer (IBL) passivates the glass surface and enhances the adhesion between the glass substrate 11 and the cover metal layer, while the base metal layer (BML) 13 and the aperture metal layer (AML) 14 minimize thermal stress during OLED manufacturing.
[0062] Figure 4 A cross-sectional view of a glass substrate fine metal mask (GS-FMM) with a double-layer interface bonding layer (IBL) structure is shown, in which alumina (Al2O3) 15 and silicon nitride (Si3N4) 16 are sequentially deposited on a glass substrate 11. However, multi-layer interface bonding layers (IBLs) can be used according to process requirements, allowing for free combination of any candidate materials, including alumina (Al2O3) 15, silicon nitride (Si3N4) 16, silicon oxynitride (SiON), hafnium oxide (HfO2), zirconium oxide (ZrO2), titanium oxide (TiO2), magnesium oxide (MgO), or aluminum nitride (AlN). The total thickness of the interface bonding layers (IBLs) ranges from 1 to 200 nm, preferably about 100 nm, and can be distributed among multiple layers as needed. A base metal layer (BML) 13, with a coefficient of thermal expansion (CTE) of less than 20 ppm / °C, is deposited on top of an interfacial bonding layer (IBL), followed by an open-cell metal layer (AML) 14 (such as Invar alloy) with a similar CTE. This dual-layer interfacial bonding layer (IBL) structure provides enhanced passivation and adhesion, ensuring stable mask performance through multiple fabrication and cleaning cycles.
[0063] Figure 5A cross-sectional view of a glass-substrate fine metal mask (GS-FMM) incorporating a multilayered metal structure is shown. In this configuration, alumina (Al2O3) 15 is deposited as an interfacial bonding layer (IBL) on a glass substrate 11, followed by an adhesion promoting layer (APL) 17. The APL 17 can be made of metals such as nickel (Ni), chromium (Cr), or titanium (Ti) to enhance the adhesion between the IBL and subsequent metal layers. A base metal layer (BML) 13 and an aperture metal layer (AML) 14 are then deposited sequentially to complete the mask structure. This design ensures strong adhesion between multilayers and maintains high structural stability during manufacturing and cleaning processes.
[0064] Figure 6 A simplified glass-substrate fine metal mask (GS-FMM) structure is demonstrated, in which only one metal layer—an aperture metal layer (AML) 14—is deposited above the interface bonding layer (IBL). This aperture metal layer (AML) 14 is made of a metal with a coefficient of thermal expansion (CTE) of less than 20 ppm / °C to minimize thermal stress during OLED manufacturing. The aperture metal layer (AML) 14 can be deposited via atomic layer deposition (ALD), chemical vapor deposition (CVD), or physical vapor deposition (PVD), depending on process requirements. This simplified structure is suitable for micro-OLED production, maintaining functionality and reliability even with a smaller number of layers.
[0065] While the above illustrations use a glass-substrate fine metal mask (GS-FMM) as a representative structure, the same configuration and principles apply to glass-substrate open metal masks (GS-OMM). Both mask types benefit from the integration of interfacial bonding layers (IBLs) such as alumina (Al2O3)15 and silicon nitride (Si3N4)16, significantly improving adhesion, passivation, and chemical resistance. IBLs can be deposited using atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), or other vapor phase methods to provide manufacturing flexibility based on process requirements. The thickness of the IBL can be adjusted from 1 to 200 nm depending on the specific application requirements to ensure optimal adhesion and protective performance.
[0066] Symbol Explanation 11: Glass substrate 12: Display area 13: Base Metal Layer (BML) 14: Aperture Metal Layer (AML) 15: Alumina (Al2O3), interfacial bonding layer (IBL) 16: Silicon nitride (Si3N4), second interface bonding layer (IBL) 17: Adhesion-enhancing layer (APL)
Claims
1. A glass substrate fine metal mask (GS-FMM) or a glass substrate open metal mask (GS-OMM), comprising: A glass substrate; One or more interfacial bonding layers (IBLs) are deposited on the glass substrate, wherein each interfacial bonding layer (IBL) is selected from one or more of metal oxides, metal nitrides or metal oxynitrides, and the interfacial bonding layers (IBLs) are used to passivate the Si-OH groups on the glass surface to prevent hydrolytic degradation and enhance the adhesion to the overlying metal layer. And one or more metal layers deposited on the interface bonding layer (IBL) to form a mask structure.
2. The mask according to claim 1, wherein the interface bonding layer (IBL) is selected from one or more of the following materials: aluminum oxide (Al2O3), silicon nitride (Si3N4), silicon oxynitride (SiON), hafnium oxide (HfO2), zirconium oxide (ZrO2), titanium oxide (TiO2), magnesium oxide (MgO) or aluminum nitride (AlN).
3. The mask according to claim 1, wherein the interface bonding layer (IBL) is formed by atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) or other vapor deposition methods.
4. The mask according to claim 1, wherein the thickness of the interface bonding layer (IBL) ranges from 1 nanometer to 200 nanometers, preferably 100 nanometers.
5. The mask according to claim 1, wherein the coefficient of thermal expansion (CTE) of the interface bonding layer (IBL) is less than 15 ppm / °C, so as to reduce the thermal stress between the glass substrate and the overlying metal layer.
6. The mask according to claim 1, wherein the one or more metal layers comprise a multilayer structure including an adhesion promoting layer (APL), a base metal layer (BML), and an opening metal layer (AML).
7. The mask of claim 1, wherein the mask comprises a single-layer metal layer (AML) deposited on an interface bonding layer (IBL).
8. The mask according to claim 1, wherein the glass substrate is plasma cleaned and then metal is deposited by physical vapor deposition (PVD).