Method for pre-treating influence on copper plating

Abstract

The invention discloses a method for influence of pretreatment on copper plating, and the method for influence of pretreatment on copper plating comprises the following steps: S11, preparing materials; s12, plasma processing equipment is arranged; s13, plasma gas is selected; s14, carrying out plasma treatment; s15, in the plasma treatment process, the change of the surface of the material is monitored in real time; s16, after the preset treatment time is up, the plasma treatment equipment is shut down, and the treated material is taken out; the method further comprises an expansion process and a degumming process. Through plasma treatment, the hydrophilicity of the surface of the material is remarkably improved, the follow-up chemical copper plating process is facilitated, protrusions on the surface of the material are increased through plasma treatment, the specific surface area and the surface roughness are increased, and the adhesive force and uniformity of a chemical copper plating layer are improved; impurities on the surface of the material are effectively removed, the surface uniformity is improved, and the quality of a chemical copper plating layer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of copper plating, specifically to a method for the influence of pretreatment on copper plating. Background Technique

[0002] Electroless copper plating is a low-cost and simple production process. The development goal of electroless copper is to chemically deposit on different materials to achieve corresponding physical properties. Electroless copper plating is mainly used in industries such as the PCB industry, packaging substrate industry, FPC, capacitive touch screen, current collector, etc. Different sub-fields have inconsistent requirements for the quality of copper deposition. The main technical indicators of concern are: appearance characteristics, thickness requirements, peel strength, internal stress, and reliability of product quality. These characteristics are all related to the coating material itself. The quality of the coating material affects the quality of the final product. Therefore, pretreatment of the material before copper plating is one of the methods to improve copper plating.

[0003] However, there are some problems in the existing electroless copper plating technology. These problems limit the quality and application range of the copper plating layer. Many non-conductive materials, such as polytetrafluoroethylene, have a low surface energy, resulting in poor surface hydrophilicity, which hinders the adsorption and reduction of copper ions on the material surface, thus affecting the electroless copper plating process; due to the microscopic unevenness of the material surface, untreated materials are prone to form uneven coatings during electroless copper plating, affecting the appearance and performance of the product; before electroless copper plating, there may be impurities such as fillers and adhesives on the material surface, and these impurities will affect the adhesion and uniformity of the coating. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for the influence of pretreatment on copper plating to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for the influence of pretreatment on copper plating, the method comprising the following steps:

[0006] S11: Prepare materials, select the base material polytetrafluoroethylene that needs to be electrolessly copper-plated;

[0007] S12: Set the plasma treatment equipment, adjust the parameters of the plasma treatment equipment, and set the power to 5 Kw and the frequency to 40 KHz;

[0008] S13: Select the plasma gas;

[0009] S14: Perform plasma treatment, put the base material into the plasma treatment equipment, introduce the selected plasma gas, and start the treatment. The treatment time is 5 - 20 min;

[0010] S15: During the plasma treatment process, monitor the changes on the material surface in real time, including the increase in hydrophilicity, the increase in surface protrusions, and the changes in specific surface area and surface roughness;

[0011] S16: After reaching the predetermined treatment time, turn off the plasma treatment equipment and take out the treated material;

[0012] The method further includes the following steps:

[0013] S21: Prepare the material, select the substrate material that needs to be electrolessly copper-plated, and ensure that the material surface is clean;

[0014] S22: Swelling treatment, put the material into the swelling equipment, set the swelling temperature to 70 - 80 °C, and the swelling time to 5 - 10 minutes to remove some fillers and impurities on the material surface and increase the surface roughness of the material;

[0015] S23: Degumming treatment, after the swelling treatment, put the material into the degumming equipment, set the degumming temperature to 75 - 85 °C, and the degumming time to 10 - 20 minutes to thoroughly remove impurities such as glue on the material surface;

[0016] The degumming treatment includes a degumming device. The degumming device includes a degumming tank. There is an opening at the top of the degumming tank. A cover plate is arranged at the opening of the degumming tank. A controller is arranged on one side of the degumming tank. An outlet pipe is arranged on one side of the degumming tank. A control valve is arranged on the outlet pipe. A driving motor is arranged on one side of the degumming tank. The output end of the driving motor is provided with a rotating shaft. The rotating shaft is rotatably connected to the degumming tank through a bearing. A rotating baffle is arranged on the outer side of the rotating shaft. The end of the rotating baffle fits on the inner side of the degumming tank. The two rotating baffles close the lower part inside the degumming tank. A support block is arranged on the top of the rotating baffle. A first adjusting screw is inserted into the support block. The first adjusting screw is internally and externally threaded with the support block. The end of the first adjusting screw is rotatably connected to a clamping block. A first gasket is arranged on the inner side of the bottom of the clamping block. A second adjusting screw is inserted into the clamping block. The bottom of the second adjusting screw is rotatably connected to a butting plate. A second gasket is arranged on the bottom of the butting plate. The first gasket and the second gasket are arranged opposite to each other. A fixing seat is arranged on one side of the rotating baffle where the support block is located. A fixing shaft is arranged on the fixing seat. A butting strip block is rotatably sleeved on the fixing shaft. A torsion spring is sleeved on the fixing shaft. One end of the torsion spring is fixedly connected to the butting strip block and the other end is fixedly connected to the fixing shaft;

[0017] S24: During the swelling and degumming processes, monitor the change in the surface roughness of the material to ensure that the surface conditions required for electroless copper plating are met;

[0018] S25: After completing the swelling and degumming steps, take out the material. At this time, the material surface should have the roughness and cleanliness suitable for electroless copper plating.

[0019] Preferably, the plasma gas includes but is not limited to H2, N2, Ar2, CF4.

[0020] Preferably, the thickness of the polytetrafluoroethylene substrate material is 10 - 100 microns.

[0021] Preferably, the degree of vacuum of the plasma processing equipment reaches 10 -3 Torr.

[0022] Preferably, the volume ratio of H2 in the plasma gas is 10 - 30%, the volume ratio of N2 is 10 - 30%, the volume ratio of Ar2 is 40 - 60%, and the volume ratio of CF4 is 5 - 15%.

[0023] Preferably, when the plasma is being processed, the distance between the substrate material and the plasma gas is 10 - 30 mm.

[0024] Preferably, the change in the hydrophilicity of the material surface is quantified using a contact angle measuring instrument.

[0025] Preferably, the substrate material is cleaned using an ultrasonic cleaner, and the cleaning time is 3 - 5 minutes.

[0026] Preferably, when monitoring the change in the surface roughness of the material, a scanning electron microscope is used for observation.

[0027] Preferably, before electroless copper plating of the material, after treatment, it is dried, the drying temperature is 60 - 80 °C, and the drying time is 10 - 15 minutes.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. Through plasma treatment in the present invention, the hydrophilicity of the material surface is significantly improved, which is beneficial to the subsequent electroless copper plating process. Plasma treatment increases the protrusions on the material surface, increases the specific surface area and surface roughness, and is beneficial to improving the adhesion and uniformity of the electroless copper plating layer.

[0030] 2. Through the expansion and degumming process in the present invention, impurities on the material surface are effectively removed, and the surface uniformity is improved, which is beneficial to improving the quality of the electroless copper plating layer. Through plasma treatment and expansion and degumming processes, the quality of the electroless copper plating layer is significantly improved, the surface is smooth and the uniformity is good. This method can reduce the removal steps of impurities such as impurities and glue on the material surface and reduce production costs.

[0031] 3. The design of the rotating baffle in the present invention enables the substrate to rotate uniformly in the degumming solution, ensuring full contact between the degumming solution and the substrate surface, improving the degumming efficiency and quality. The use of the first adjusting screw and the second adjusting screw enables the device to adapt to substrates of different sizes and shapes, improving the versatility of the equipment. The clamping block and the abutting plate fix the substrate, and the torsion spring provides elastic force to ensure the stability of the substrate during the degumming process, preventing it from moving due to the centrifugal force and ensuring the stability of the degumming process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flowchart of the plasma treatment method of the present invention.

[0033] Figure 2 It is a flowchart of the swelling degumming treatment method of the present invention.

[0034] Figure 3 It is a schematic structural diagram of the degumming device of the present invention.

[0035] Figure 4 It is a schematic structural diagram of the interior of the degumming tank of the present invention.

[0036] Figure 5 For the present invention Figure 4 The enlarged schematic structural diagram at position A in.

[0037] Figure 6 It is a schematic structural diagram of the fixing seat of the present invention.

[0038] In the figure: degumming tank 1; opening 2; cover plate 3; controller 4; liquid outlet pipe 5; drive motor 6; rotating shaft 61; rotating baffle 62; support block 7; first adjusting screw 71; clamping block 72; first gasket 73; second adjusting screw 74; abutting plate 75; second gasket 76; fixing seat 8; fixing shaft 81; abutting strip 82; torsion spring 83. SPECIFIC EMBODIMENTS

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] Please refer to Figures 1 to 2 , the present invention provides a technical solution: a method for the influence of pretreatment on copper plating, the method includes the following steps:

[0041] S11: Prepare the substrate material, and select polytetrafluoroethylene with a thickness of 50 microns as the substrate material for electroless copper plating;

[0042] S12: Set up the plasma processing equipment, adjust the parameters of the plasma processing equipment, set the power to 5 Kw, the frequency to 40 KHz, and ensure that the vacuum degree of the equipment reaches 10^-3 Torr;

[0043] S13: Select the plasma gas. According to the characteristics of the substrate material, select a plasma gas mixture, in which the volume ratio of H2 is 20%, the volume ratio of N2 is 20%, the volume ratio of Ar2 is 50%, and the volume ratio of CF4 is 10%;

[0044] S14: Conduct plasma processing. Place the substrate material into the plasma processing equipment, keep the distance between the material and the plasma gas at 20 mm, introduce the plasma gas, and start the processing. The processing time is set to 15 minutes;

[0045] S15: Monitor the surface changes of the material. During the plasma processing, use a contact angle measuring instrument to monitor the hydrophilicity changes of the material surface in real time, and use a scanning electron microscope to observe the increase in surface protrusions and the changes in specific surface area and surface roughness;

[0046] S16: Complete the processing. After reaching the predetermined processing time, turn off the plasma processing equipment, take out the processed material, and cool it to room temperature in a dust-free environment.

[0047] This method further includes the following steps:

[0048] S21: Prepare the substrate material. Select polytetrafluoroethylene with a thickness of 50 microns as the substrate material for electroless copper plating, and use an ultrasonic cleaner for cleaning. The cleaning time is 4 minutes to ensure the cleanliness of the material surface;

[0049] S22: Expansion treatment. Place the material into the expansion equipment, set the expansion temperature to 75 degrees Celsius, and the expansion time to 8 minutes to remove some fillers and impurities on the material surface and increase the surface roughness of the material;

[0050] S23: Degumming treatment. After the expansion treatment, place the material into the degumming equipment. The degumming temperature is set to 75 - 85 degrees Celsius, and the degumming time is 10 - 20 minutes to thoroughly remove impurities such as glue on the material surface;

[0051] The degumming treatment includes a degumming device. The degumming device includes a degumming tank 1, which is used to hold the degumming liquid and the workpiece and is the main container for the degumming treatment. An opening 2 is provided at the top of the degumming tank 1, which facilitates the putting in and taking out of the workpiece. A cover plate 3 is lapped at the opening 2 of the degumming tank 1. A controller 4 is installed on one side of the degumming tank 1, which is used to control the operating parameters of the degumming device, such as temperature, time, and stirring speed. A high-temperature generator is installed on the degumming tank 1, which is not shown in the attached drawings and is a common device in the prior art and will not be elaborated here. An outlet pipe 5 is installed on one side of the degumming tank 1, and a control valve is installed on the outlet pipe 5. The outlet pipe 5 is used to discharge the waste liquid in the degumming tank.

[0052] A driving motor 6 is fixedly installed on one side of the degumming tank 1. The output end of the driving motor 6 is fixedly connected to a rotating shaft 61. The rotating shaft 61 is rotatably connected to the degumming tank 1 through a bearing. A rotating baffle 62 is fixedly connected to the outside of the rotating shaft 61. The end of the rotating baffle 62 fits against the inside of the degumming tank 1. The height of the degumming liquid is flush with the bottom of the rotating baffle 62 in the horizontal state. The two rotating baffles 62 close the lower part inside the degumming tank 1 to ensure the relative constancy of the temperature.

[0053] Inject the degumming liquid into the degumming tank 1, then set the parameters of the degumming process, such as temperature and time, through the controller 4. Open the cover plate 3, put the workpiece to be degummed into the degumming tank 1, then cover the cover plate 3 again to seal the degumming tank 1. Start the driving motor 6, the rotating shaft 61 starts to rotate, driving the rotating baffle 62 to rotate, so that the substrate is in full contact with the degumming liquid and the degumming liquid is stirred. The controller 4 adjusts the temperature of the degumming liquid according to the preset parameters to ensure that the degumming process is carried out at an appropriate temperature.

[0054] A support block 7 is fixedly connected to the top of the rotating baffle 62. A first adjusting screw 71 is inserted into the support block 7. The first adjusting screw 71 is connected with the support block 7 by internal and external threads. The end of the first adjusting screw 71 is rotatably connected to a clamping block 72. A first gasket 73 is welded on the inner side of the bottom of the clamping block 72. The first gasket 73 is made of a strong alkali-resistant material, 316 stainless steel. The end of the first gasket 73 is in an arc-shaped structure and is distributed at intervals, which is used for the comprehensiveness of subsequent substrate degumming. By connecting the support block 7 with internal and external threads, the distance between the two clamping blocks 72 is adjusted. The two clamping blocks 72 are used to fix the substrate.

[0055] A second adjusting screw 74 is inserted into the clamping block 72. The bottom of the second adjusting screw 74 is rotatably connected to a contact plate 75. A second gasket 76 is welded to the bottom of the contact plate 75. The first gasket 73 and the second gasket 76 are arranged opposite to each other. The second gasket 76 is made of a strong alkali-resistant material, 316 stainless steel. The end of the second gasket 76 is in an arc-shaped structure and is distributed at intervals.

[0056] On one side of the support block 7 on the rotating baffle 62, there is a fixedly connected fixing seat 8. On the fixing seat 8, there is a fixedly connected fixing shaft 81. A contacting strip block 82 is rotatably sleeved on the fixing shaft 81. A torsion spring 83 is sleeved on the fixing shaft 81. The surface of the torsion spring 83 is added with a strong alkali-resistant material, using 316 stainless steel. One end of the torsion spring 83 is fixedly connected to the contacting strip block 82, and the other end is fixedly connected to the fixing shaft 81.

[0057] The substrate is placed at the bottom of the rotating baffle 62 and fixed by the clamping blocks 72 and the contacting plates 75 on both sides. The first adjusting screw 71 and the second adjusting screw 74 are used to adjust the position and pressure of the substrate to ensure the stability of the substrate during the debonding process. The torsion spring 83 provides elastic force to keep the contacting strip block 82 in contact with the substrate, preventing the substrate from moving due to centrifugal force during the rotation of debonding.

[0058] S24: Monitor the change in the surface roughness of the material. During the swelling and debonding processes, use SEM to monitor the change in the surface roughness of the material to ensure that the surface conditions required for electroless copper plating are achieved.

[0059] S25: Complete the pretreatment. After completing the swelling and debonding steps, take out the material. At this time, the surface of the material should have the roughness and cleanliness suitable for electroless copper plating.

[0060] Before electroless copper plating, the treated material is dried. The drying temperature is 60 - 80 °C, and the drying time is 10 - 15 minutes.

[0061] Adopt the methods of swelling and debonding to pretreat the materials for electroless copper plating, mainly to remove impurities such as fillers and adhesives on the surface of the materials and increase the surface roughness. As shown in the following table

[0062]

[0063] As can be seen from the above table, by the methods of swelling and debonding, the surface roughness of the raw materials for electroless copper plating can be increased, which greatly improves the copper plating quality of the materials. In addition, the surface roughness of the coating is also related to the swelling temperature, swelling time, debonding temperature, and debonding time.

[0064] The quality of electroless copper plating is closely related to the pretreatment of the materials for copper plating. Through plasma treatment or swelling and debonding processes, the specific surface area of the copper-plated materials can be increased, the roughness of the materials can be increased, and thus the quality of electroless copper plating can be increased.

[0065] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for the effect of pretreatment on copper plating, characterized in that: The method comprises the following steps: S11: Prepare materials and select polytetrafluoroethylene, a base material to be subjected to chemical copper plating; S12: Setting the plasma treatment equipment, adjusting the parameters of the plasma treatment equipment, setting the power to 5Kw and the frequency to 40KHz; S13: Selecting plasma gas; S14: Plasma treatment is performed, the substrate material is placed in a plasma treatment device, a selected plasma gas is introduced, and treatment is started, and the treatment time is 5-20 minutes; S15: During the plasma treatment process, real-time monitoring of changes in the material surface, including the increase in hydrophilicity, the increase in surface protrusions, and the changes in specific surface area and surface roughness; S16: After the predetermined processing time is reached, the plasma processing equipment is turned off and the processed material is taken out; The method further comprises the following steps: S21: Prepare materials, select the base material that needs to be electrolessly copper plated, and ensure that the surface of the material is clean; S22: expansion treatment, placing the material into an expansion device, setting the expansion temperature to 70-80 degrees Celsius, and the expansion time to 5-10 minutes, so as to remove some fillers and impurities on the surface of the material and increase the roughness of the surface of the material; S23: Glue removal treatment: after the expansion treatment, the material is placed in the glue removal equipment, the glue removal temperature is set to 75-85 degrees Celsius, the glue removal time is 10-20 minutes, and the glue and other impurities on the surface of the material are completely removed; The degumming treatment comprises a degumming device, which comprises a degumming pool (1), an opening (2) is arranged at the top of the degumming pool (1), a cover plate (3) is arranged on the degumming pool (1) at the opening (2), a controller (4) is arranged on one side of the degumming pool (1), a liquid outlet pipe (5) is arranged on one side of the degumming pool (1), a control valve is arranged on the liquid outlet pipe (5), a driving motor (6) is arranged on one side of the degumming pool (1), a rotating shaft (61) is arranged at the output end of the driving motor (6), the rotating shaft (61) is rotatably connected to the degumming pool (1) through a bearing, a rotating baffle (62) is arranged on the outer side of the rotating shaft (61), the end of the rotating baffle (62) is attached to the inner side of the degumming pool (1), the rotating baffles (62) on both sides seal the lower part of the interior of the degumming pool (1), a supporting block (7) is arranged on the top of the rotating baffle (62), and a first adjusting screw (71) is inserted into the supporting block (7). ), the first adjusting screw (71) and the supporting block (7) are connected by internal and external threads, the end of the first adjusting screw (71) is rotatably connected to a clamping block (72), a first gasket (73) is provided on the inner side of the bottom of the clamping block (72), a second adjusting screw (74) is inserted into the clamping block (72), the bottom of the second adjusting screw (74) is rotatably connected to an abutment plate (75), the bottom of the abutment plate (75) is provided with a second gasket (76), the first gasket The sheet (73) and the second gasket (76) are arranged opposite to each other, a fixed seat (8) is arranged on the rotating baffle (62) at one side of the supporting block (7), a fixed shaft (81) is arranged on the fixed seat (8), an abutting bar (82) is rotatably sleeved on the fixed shaft (81), a torsion spring (83) is sleeved on the fixed shaft (81), one end of the torsion spring (83) is fixedly connected to the abutting bar (82), and the other end is fixedly connected to the fixed shaft (81); S24: During the expansion and debonding process, monitor the roughness change of the material surface to ensure that the surface conditions required for chemical copper plating are met; S25: After the expansion and degumming steps are completed, the material is taken out. At this time, the surface of the material should have a roughness and cleanliness suitable for chemical copper plating.

2. The method for the effect of pretreatment on copper plating according to claim 1, characterized in that: The plasma gas includes but is not limited to H2, N2, Ar2, and CF4.

3. The method for the effect of pre-treatment on copper plating according to claim 1, characterized in that: The thickness of the base material polytetrafluoroethylene is 10-100 microns.

4. The method for the effect of pretreatment on copper plating according to claim 1, characterized in that: The vacuum degree of the plasma treatment equipment reaches 10 -3 Entrust.

5. The method for the effect of pre-treatment on copper plating according to claim 2, characterized in that: The volume proportion of H2 in the plasma gas is 10-30%, the volume proportion of N2 is 10-30%, the volume proportion of Ar2 is 40-60%, and the volume proportion of CF4 is 5-15%.

6. The method for the effect of pre-treatment on copper plating according to claim 2, characterized in that: When the plasma is being processed, the distance between the substrate material and the plasma gas is 10-30 mm.

7. The method for the effect of pretreatment on copper plating according to claim 1, characterized in that: The change in hydrophilicity of the material surface was quantified using a contact angle meter.

8. The method for the effect of pre-treatment on copper plating according to claim 1, characterized in that: The base material is cleaned using an ultrasonic cleaner for 3-5 minutes.

9. The method for the effect of pre-treatment on copper plating according to claim 1, characterized in that: When monitoring the change of the surface roughness of the material, a scanning electron microscope is used for observation.

10. The method for the effect of pretreatment on copper plating according to claim 1, characterized in that: The material is dried before chemical copper plating, the drying temperature is 60-80 degrees Celsius, and the drying time is 10-15 minutes.

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