A process for copper coating on transparent polymer surface

Abstract

The present invention discloses a process for copper coating on a transparent polymer surface, comprising: S01 plasma cleaning the transparent polymer surface; S02 depositing a multilayer oxide layer on the transparent polymer surface; S03 plasma etching the transparent polymer surface; and S04 copper coating the transparent polymer surface. By designing a unique process for copper coating on a transparent polymer surface, the present invention uses this process to produce fine copper-clad polymer circuits, completely resolving the technical challenge of dendrite formation in environments with narrow line widths and line spacings.

Description

Technical Field

[0001] The invention discloses a process for copper coating on the surface of a transparent polymer. Background Art

[0002] Flexible displays refer to deformable and bendable display devices made of soft materials. Currently, flexible LEDs and OLEDs are the mainstream, with flexible liquid crystal displays (LCDs) also developing in parallel. As LED and OLED technologies mature, a variety of products utilizing these technologies have emerged. A light-emitting diode (LED) display is a device system that displays information by controlling the light emission of an LED matrix. In certain special applications, such as glass curtain walls, store windows, 3D billboards, and stage backdrops, LED display modules require high light transmittance. Furthermore, bendable and retractable displays facilitate installation, transportation, and maintenance in non-planar areas. Achieving high bonding strength and a long lifespan for transparent polymer copper-clad substrates has always been a technical challenge in this industry. Furthermore, the problem of dendrites caused by electromigration in fine circuits during actual use is a significant factor affecting the lifespan of transparent devices.

[0003] The generation of dendrites during use in fine circuits, leading to circuit failure, has long been a technical bottleneck in the industry. Fine circuits have narrow line widths and spacings, and transparent polymers easily absorb water. This, under the action of an electric field, causes copper migration and dendrite growth, leading to interconnection between two lines and rendering the circuits useless. Traditionally, a covering film has been added, but this only addresses the problem on the upper surface; the copper on the lower surface still faces dendrite growth after the polymer matrix absorbs water. This invention primarily addresses the technical challenge of dendrites by designing a special method for copper-coating a transparent polymer surface. This method, used to prepare fine circuits etched with copper-coated polymers, completely avoids dendrite formation in environments with narrow line widths and spacings. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a process for copper coating on the surface of a transparent polymer to address the problems existing in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A process for copper coating on a transparent polymer surface, the process specifically comprising the following steps:

[0007] S01 Surface plasma cleaning of transparent polymers:

[0008] The transparent polymer surface is sequentially cleaned with a Penning source and a Kaufman source to achieve oxygen embedding and oxygen addition, and then used for standby;

[0009] Among them, during the Penning source cleaning process, the high energy of oxygen ions facilitates the combination of O and H, thereby achieving the formation of hydroxyl free radicals, and the number of hydroxyl free radicals on the surface of the transparent polymer should not be less than 10%;

[0010] And, in the Kaufman source cleaning process, in order to achieve oxygen addition, the resistance is lower than 10 16 Ω; and oxygen combines with C to form a bond, and the CO bond is conducive to the increase of surface energy; but if the surface resistance exceeds 10 16 Ω, the Penning source treatment is repeated, and after the gas plasma cleaning is completed, the transmittance does not drop more than 5%. (Because the higher the resistance, the less CO bonds, OH groups, and C groups are formed on the surface, which is directly related to the hydrophilicity of the polymer surface).

[0011] In addition, after the low-energy cleaning, the surface roughness of the substrate is 0.1-0.4 microns. Roughness that is too high or too low cannot meet practical requirements, and the roughness parameters need to be controlled by adjusting parameters such as the air intake volume.

[0012] S02 deposits multilayer oxides on transparent polymer surfaces:

[0013] Using low-energy ion beam technology, a layer of oxide is first deposited on the surface of the transparent polymer treated with SO1. After the deposition is completed, the oxygen supply is stopped and a thin layer of metal is deposited. The oxide layer and the thin metal layer are set as a unit cycle. The cycle is repeated 1-20 times to complete the deposition of multiple layers of oxide.

[0014] S03 plasma etching of multi-layer oxides on the surface of transparent polymer:

[0015] Plasma etching of the surface oxide of the transparent polymer treated with SO2 using plasma technology:

[0016] S04 copper coating on the oxide layer of transparent polymer:

[0017] The process of copper coating the surface of the transparent polymer is completed by depositing extremely thin copper using low-energy ion beam technology and electron beam evaporation technology.

[0018] It should be noted that in step S02, the same oxide multilayer or mixed oxide multilayer can be used; and after the deposition is completed, the surface roughness of the oxide is between 0.01-0.1 μm, and the transmittance decreases by no more than 8%.

[0019] In addition, the addition of the metal layer can not only significantly improve the toughness of the oxide and reduce the internal stress by more than 50%, but also realize the absorption and solidification of water and oxygen, etc., greatly improving the overall water vapor stability; and controlling the thickness ratio of the metal layer and the oxide layer between 0.02-0.2 to significantly enhance the transmittance of light and maintain the light transmittance of the transparent polymer; furthermore, the metal / metal oxide multilayer structure plays a vital role in the overall resistance to water vapor intrusion into copper. For transparent polymers with high water absorption, it can greatly reduce the water vapor entering the copper on this side of the polymer, greatly reducing the probability of dendrite formation.

[0020] Preferably, in step S01, the Penning source cleaning voltage is 20-40 KV, the processing time is 1-5 min, and the oxygen flow rate is 10-50 sccm.

[0021] Furthermore, in step S01, the Kaufman source cleaning voltage is 10-20 KV, the processing time is 1-5 min, and the oxygen flow rate is 10-50 sccm.

[0022] Preferably, the deposition thickness of the oxide is 10-20 nm, and the deposition thickness of the thin metal layer is 1-5 nm; and the oxide is at least one of aluminum oxide, magnesium oxide, and zirconium oxide.

[0023] Furthermore, the deposition beam current is 100-400 mA, the temperature during the deposition process is 100-150° C., the deposition rate is 10-40 nm / min, and the oxygen flow rate is 20-80 sccm.

[0024] Preferably, in step S03, the etching beam current is 100-800 mA, the etching time is 1-5 min, the etching depth is 1-5 nm, and the width is 3-10 nm.

[0025] It is worth noting that plasma etching of the multilayer oxide on the surface of the transparent polymer can not only increase the overall light transmittance by 1-7%, but also increase the number of dangling bonds on the surface of the transparent polymer by more than 10%.

[0026] Preferably, in step S04, the current during ion beam deposition is 90-200 A, the beam current is >600 mA, and the deposition rate is not less than 10 nm / min; the electron beam evaporation power is not less than 30 kW, the deposition rate is not greater than 5 μm / min, the roll-to-roll speed is not less than 3 m / min, the thickness of the copper foil is 3-8 μm, and the surface roughness of the copper foil is 0.05-0.2 μm.

[0027] By coating the surface of the transparent polymer oxide layer with copper, the thickness uniformity within a width of 500mm can be reduced to no more than 8%, the copper foil can be folded no less than 1,500 times, the consumption factor is less than 0.04, the water absorption rate is less than 4%, and the extended tear strength is greater than 4g.

[0028] Compared with the prior art, the process for copper coating on a transparent polymer surface disclosed in the present invention has the following advantages:

[0029] 1. The present invention proposes a process for copper coating on a transparent polymer surface. By cleaning the polymer and adding it, the polymer matrix has a very good bonding strength with the oxide layer and the subsequent copper film layer, thereby enhancing its peel strength.

[0030] 2. The gas ion source is highly operable in cleaning, resulting in good physical and chemical stability of the polymer after treatment;

[0031] 3. The nanostructure based on Hall ion source micro-etching has a hydrophilic structure and a large specific surface area, which can greatly increase the surface energy and also has anti-reflection properties;

[0032] 4. The present invention can perfectly avoid the formation of dendrites caused by electromigration due to water vapor during use, thereby solving the technical bottleneck problem of ultra-fine circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] Figure 1 Flowchart of the copper-clad process on transparent polymer surfaces.

[0035] Figure 2 Schematic diagram of the structure of copper clad on the surface of transparent polymer.

[0036] Figure 3 Graph showing the copper foil bonding strength of Examples 1-4.

[0037] Figure 4 The number of dendrites per square millimeter in Examples 1-4 (100h in a double 85 environment, voltage 50V).

[0038] Figure 2 middle:

[0039] 201 transparent polymer substrate, 202 multi-layer oxide adjustment layer, 203 copper cladding layer. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0041] In order to better understand the present invention, the following Figure 1 The present invention is further specifically described in the following examples, but they should not be construed as limiting the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the above invention contents are also considered to fall within the scope of protection of the present invention.

[0042] Example 1:

[0043] S01: None

[0044] S02: depositing multiple layers of oxide on the transparent polymer using low-energy ion beam technology to perform multi-layer oxidation deposition on the polymer, first depositing a first oxide layer of aluminum oxide with a deposition thickness of 10-20 nm, with deposition parameters such as a beam current of 100-400 mA, a temperature of 100-150° C. during deposition, a deposition rate of 10-40 nm / min, and an oxygen flow rate of 20-80 sccm; after the first oxide layer is completed, the oxygen supply is stopped, and a second ultra-thin metal layer is deposited with a deposition thickness of 1-5 nm; the first oxide layer and the second metal layer constitute a unit cycle, and the number of cycles repeated is 1-20 times;

[0045] S03: Plasma etching of multilayer oxides on transparent polymer surfaces

[0046] The polymer surface oxide is etched by plasma, with an etching beam current of 100-800mA, an etching time of 1-5min, an etching depth of 1-5nm, and a width of 3-10nm.

[0047] S04: Copper cladding on the surface of transparent polymer oxide layer

[0048] Low-energy ion beam technology and electron beam evaporation technology are used to deposit extremely thin copper. During ion beam deposition, the current is 90-200A, the beam current is >600mA, and the deposition rate is 10nm / min; the electron beam evaporation power is not less than 30KW, the deposition rate is 3μm / min, the roll-to-roll speed is 3m / min, and the thickness of the copper foil is 5μm.

[0049] Example 2:

[0050] S01: Roll-to-roll plasma cleaning of transparent polymer, followed by Penning source cleaning and Kaufman cleaning: Penning source voltage 20-40KV, processing time 1-5min, oxygen flow rate 10-50sccm; Kaufman source voltage 10-20KV, processing time 1-5min, oxygen flow rate 10-50sccm, resistance less than 10 16 Ω;

[0051] S02: None

[0052] S03: None

[0053] S04: Copper cladding on the surface of transparent polymer oxide layer

[0054] Low-energy ion beam technology and electron beam evaporation technology are used to deposit extremely thin copper. During ion beam deposition, the current is 90-200A, the beam current is >600mA, and the deposition rate is 10nm / min; the electron beam evaporation power is not less than 30KW, the deposition rate is 3μm / min, the roll-to-roll speed is 3m / min, and the thickness of the copper foil is 5μm.

[0055] Example 3:

[0056] S01: Roll-to-roll plasma cleaning of transparent polymer, followed by Penning source cleaning and Kaufman cleaning: Penning source voltage 20-40KV, processing time 1-5min, oxygen flow rate 10-50sccm; Kaufman source voltage 10-20KV, processing time 1-5min, oxygen flow rate 10-50sccm, resistance less than 10 16 Ω;

[0057] S02: depositing multiple layers of oxide on the transparent polymer using low-energy ion beam technology to perform multi-layer oxidation deposition on the polymer, first depositing the first oxide layer, which is aluminum oxide, with a deposition thickness of 15 nm, with deposition parameters such as a beam current of 100-400 mA, a temperature of 100-150° C. during deposition, a deposition rate of 20 nm / min, and an oxygen flow rate of 20-80 sccm; after the first oxide layer is completed, the oxygen supply is stopped, and a second ultra-thin metal layer is deposited with a deposition thickness of 1 nm; the first oxide layer and the second metal layer constitute a unit cycle, and the cycle is repeated 15 times;

[0058] S03: Plasma etching of multilayer oxides on transparent polymer surfaces

[0059] The polymer surface oxide is etched by plasma, with an etching beam current of 100-800mA, an etching time of 1-5min, an etching depth of 1-5nm, and a width of 3-10nm.

[0060] S04: Copper cladding on the surface of transparent polymer oxide layer

[0061] Low-energy ion beam technology and electron beam evaporation technology are used to deposit extremely thin copper. During ion beam deposition, the current is 90-200A, the beam current is >600mA, and the deposition rate is 10nm / min; the electron beam evaporation power is not less than 30KW, the deposition rate is 3μm / min, the roll-to-roll speed is 3m / min, and the thickness of the copper foil is 5μm.

[0062] Example 4:

[0063] S01: Roll-to-roll plasma cleaning of transparent polymer, followed by Penning source cleaning and Kaufman cleaning: Penning source voltage 20-40KV, processing time 1-5min, oxygen flow rate 10-50sccm; Kaufman source voltage 10-20KV, processing time 1-5min, oxygen flow rate 10-50sccm, resistance less than 10 16 Ω;

[0064] S02: depositing multiple layers of oxide on the transparent polymer using low-energy ion beam technology to perform multi-layer oxidation deposition on the polymer, first depositing the first oxide layer, which is aluminum oxide, with a deposition thickness of 20 nm, with deposition parameters such as a beam current of 100-400 mA, a temperature of 100-150° C. during deposition, a deposition rate of 20 nm / min, and an oxygen flow rate of 20-80 sccm; after the first oxide layer is completed, the oxygen supply is stopped, and a second ultra-thin metal layer is deposited with a deposition thickness of 3 nm; the first oxide layer and the second metal layer constitute a unit cycle, and the cycle is repeated 15 times;

[0065] S03: Plasma etching of multilayer oxides on transparent polymer surfaces

[0066] The polymer surface oxide is etched by plasma, with an etching beam current of 100-800mA, an etching time of 1-5min, an etching depth of 1-5nm, and a width of 3-10nm.

[0067] S04: Copper cladding on the surface of transparent polymer oxide layer

[0068] Low-energy ion beam technology and electron beam evaporation technology are used to deposit extremely thin copper. During ion beam deposition, the current is 90-200A, the beam current is >600mA, and the deposition rate is 10nm / min; the electron beam evaporation power is not less than 30KW, the deposition rate is 3μm / min, the roll-to-roll speed is 3m / min, and the thickness of the copper foil is 5μm.

[0069] Depend on Figure 3 As shown, the bonding strength of Example 1 without plasma cleaning is greatly affected, with a bonding strength of 0.32 N / cm. The bonding strength of Example 2 is 0.81 N / cm. The bonding strengths of Examples 3 and 4 are 0.79 and 0.76 N / cm, respectively. The addition of multilayer oxide has a side effect on the bonding strength, and the introduction of multiple layers can significantly reduce the impact on the bonding strength.

[0070] Depend on Figure 4 As shown, Example 1, without plasma cleaning, significantly impacts the compactness of the multilayer oxide. After 100 hours in a dual 85 environment at 50V, the number of dendrites is 8 per square millimeter. However, the greatest impact is achieved by the absence of multilayer oxide, with a dendrite count of 32, indicating complete failure. Examples 3 and 4 both achieved zero dendrites, demonstrating that the addition of multilayer oxide significantly suppresses dendrite formation.

[0071] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for copper coating on a transparent polymer surface, characterized in that: The process specifically comprises the following steps: S01 Surface plasma cleaning of transparent polymers: The transparent polymer surface is sequentially cleaned with a Penning source and a Kaufman source to achieve oxygen embedding and oxygen addition, and then used for standby; The resistance of the Kaufman source during cleaning is less than 10 16 Ω; S02 deposits multilayer oxides on transparent polymer surfaces: Using low-energy ion beam technology, a layer of oxide is first deposited on the surface of the transparent polymer treated with SO1. After the deposition is completed, the oxygen supply is stopped and a thin layer of metal is deposited. The oxide layer and the thin metal layer are set as a unit cycle. The cycle is repeated 1-20 times to complete the deposition of multiple layers of oxide. The deposited thickness of the oxide is 10-20 nm, and the deposited thickness of the thin metal layer is 1-5 nm; and the oxide is at least one of aluminum oxide, magnesium oxide, and zirconium oxide; The deposition beam current is 100-400 mA, the temperature during deposition is 100-150° C., the deposition rate is 10-40 nm / min, and the oxygen flow rate is 20-80 sccm. S03 plasma etching of multi-layer oxides on the surface of transparent polymer: Plasma etching is performed on the surface oxide of the transparent polymer treated with SO2 using plasma technology; S04 copper coating on the oxide layer of transparent polymer: The process of copper coating the surface of the transparent polymer is completed by depositing extremely thin copper using low-energy ion beam technology and electron beam evaporation technology.

2. The process for copper coating on a transparent polymer surface according to claim 1, characterized in that: In step S01, the Penning source cleaning voltage is 20-40 KV, the processing time is 1-5 min, and the oxygen flow rate is 10-50 sccm.

3. The process for copper coating on a transparent polymer surface according to claim 1 or 2, characterized in that: In step S01, the Kaufman source cleaning voltage is 10-20 KV, the processing time is 1-5 minutes, and the oxygen flow rate is 10-50 sccm.

4. The process for copper coating on a transparent polymer surface according to claim 1, wherein: In step S03, the etching beam current is 100-800 mA, the etching time is 1-5 min, the etching depth is 1-5 nm, and the width is 3-10 nm.

5. The process for copper coating on a transparent polymer surface according to claim 1, characterized in that: In step S04, the current during ion beam deposition is 90-200A, the beam current is >600mA, and the deposition rate is not less than 10nm / min; the electron beam evaporation power is not less than 30KW, the deposition rate is not greater than 5μm / min, the roll-to-roll speed is not less than 3m / min, the thickness of the copper foil is 3-8μm, and the surface roughness of the copper foil is 0.05-0.2μm.

Images