Plasma etching apparatus and method for etching a resist

Abstract

The application discloses a kind of plasma etching equipment and etching glue removing method, by embedding permanent magnet group in electrode plate, the magnetization surface of permanent magnet group and the plane of electrode plate are perpendicular to each other, the magnetization surface of the permanent magnet group and the plane of the electrode plate are perpendicular to each other, to make the magnetic field generated between different electrode plates in energized state and the alternating electric field generated on the electrode plate perpendicular to each other, under the action of alternating electric field, reaction gas is ionized into plasma, by the reasonable arrangement of magnetic field, under the action of magnetic field, the concentration and chemical activity of plasma increase, to improve the etching speed and uniformity of the residue glue in hole.

Description

Technical Field

[0001] This invention relates to the field of plasma etching technology, and in particular to a plasma etching apparatus and a method for etching and removing resist. Background Technology

[0002] In the fabrication of printed circuit boards, especially high-density interconnect circuit boards, after laser-processed blind vias or mechanically drilled through-holes, a via metallization process is required to enable electrical conduction between layers through the metallized vias. However, due to the localized high temperatures generated during the drilling process of laser-drilled or mechanically drilled vias, residual adhesive material often remains inside the vias after drilling. To prevent quality problems in the subsequent metallization process, this material must be removed before metallization.

[0003] Currently, plasma etching equipment is the most commonly used method in the industry for removing residual adhesive inside holes. The principle is to evacuate the cavity containing the circuit board, then introduce oxygen and carbon tetrafluoride gas. A high-frequency converted high-voltage electric field is applied to the electrode plates on both sides of the circuit board, causing the gas to generate active plasma. In this way, the surface of the component to be cleaned is bombarded under the dual action of physical and chemical processes, turning the polymer residue to be removed from the surface into ions or gas. After vacuuming, the residue is removed from the surface and inside the holes, thus achieving the cleaning purpose.

[0004] However, with the rapid development of the electronics industry in recent years, the ever-increasing functions and requirements in fields such as 5G communication, AI artificial intelligence, telecommunications, military, aviation and aerospace, and medical applications have driven the demand for complex, high-performance circuit boards. This has led to high-density multilayer board structures, high-TG rigid boards ranging from 4 to 48 layers or more, double-sided PTFE, mixed-pressure PTFE multilayer boards, ceramic resin composite substrates, multilayer flexible boards, and rigid-flex boards. These high-end board structures seek high aspect ratios and smaller hole diameters, making it more difficult to remove contaminants from the drilled holes. In addition, some 5G circuit board products have large panel sizes, with single board dimensions exceeding 685.8 mm. To improve the capacity of plasma desmearing, large-cavity plasma machines have begun to be gradually applied, but the large-cavity design does not provide ideal uniformity for desmearing.

[0005] To improve the etching and degumming rate, the industry has adopted several measures, such as increasing electrode power, gas flow rate, and chamber temperature. While these methods have some effect, they increase production costs, and beyond a certain point, the speed improvement becomes insignificant, and may even lead to board burn-out. To improve the uniformity of plasma etching and degumming, the current approach is primarily to alter the gas flow field distribution, such as optimizing the inlet pipe layout, adjusting the outlet baffle opening size, and adding openings to the electrodes or mounting brackets. While these methods have some effect, as the chamber size increases, these approaches based on changing the airflow field are insufficient to meet the higher demands for etching and degumming speed and uniformity.

[0006] Therefore, there is an urgent need to develop an etching device that improves the ability to remove adhesive and the uniformity of etching. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a plasma etching apparatus and an etching and resist removal method to improve etching speed and resist removal uniformity.

[0008] In view of this purpose, embodiments of the present invention provide a plasma etching apparatus, including an etching chamber, wherein an etching chamber is formed inside the etching chamber; the etching chamber is provided with an inlet for filling with reactive gas and an exhaust port for evacuation; a plurality of first electrode plates and second electrode plates are disposed in the etching chamber, the first electrode plates and second electrode plates are arranged parallel to each other and spaced apart, an alternating electric field is generated between the first electrode plates and second electrode plates when energized, and a magnetic field perpendicular to the alternating electric field is provided between the first electrode plates and second electrode plates.

[0009] Optionally, the etching chamber is divided into a first region and a second region, and the magnetic field includes a first magnetic field and a second magnetic field. The first magnetic field is arranged in the first region, and the second magnetic field is arranged in the second region.

[0010] The plasma density in the first region is greater than the plasma density in the second region, and the magnetism of the first magnetic field is less than that of the second magnetic field.

[0011] Optionally, both the first electrode plate and the second electrode plate are provided with a plurality of mounting slots in parallel, and a group of permanent magnets for generating a magnetic field perpendicular to the alternating electric field is installed in the mounting slots.

[0012] Optionally, the permanent magnet groups in each column are spaced 10mm to 150mm apart.

[0013] Optionally, it further includes a first conductive rod, a second conductive rod, and a power source, wherein the positive terminal of the power source is connected to the first electrode plate through the first conductive rod, and the negative terminal of the power source is connected to the second electrode plate through the second conductive rod.

[0014] Optionally, the etching chamber is provided with an air inlet pipe assembly, which is connected to an air supply device; a flow meter is connected to the air inlet of the air inlet pipe assembly, which is used to monitor the gas flow rate flowing into the etching chamber from the air inlet.

[0015] Optionally, the bottom of the etching chamber is provided with the air extraction port, and the etching chamber is connected to a vacuum pump through the air extraction port; an air extraction baffle is provided on the inner side of the etching chamber near the air extraction port, and the air extraction baffle is used to uniformly discharge the residual etching gas.

[0016] Optionally, a pressure gauge is provided on the side of the etching chamber, and the pressure gauge is connected to the etching chamber to detect the real-time pressure inside the etching chamber.

[0017] In addition, an etching method for removing adhesive is provided, using the aforementioned plasma etching equipment, comprising the following steps:

[0018] The printed circuit board to be de-adhesive-removed is placed in the etching chamber;

[0019] The pressure inside the etching chamber is brought to a preset pressure value.

[0020] A first mixed reactive gas is introduced into the etching chamber, and the first electrode plate and the second electrode plate are energized to generate an alternating electric field perpendicular to the magnetic field. The molecules in the first mixed reactive gas are ionized under the action of the alternating electric field and the magnetic field to form a first plasma, which then bombards the printed circuit board to make the temperature of the printed circuit board reach a preset temperature value.

[0021] A second mixed reactive gas is introduced into the etching chamber. The molecules of the second mixed reactive gas are ionized under the action of the alternating electric field and magnetic field to form a second plasma, which then etches away the residual adhesive on the printed circuit board.

[0022] Optionally, the first mixed reaction gas includes oxygen and nitrogen; the second mixed reaction gas includes oxygen and carbon tetrafluoride.

[0023] The beneficial effects of the present invention: The embodiments of the present invention provide a plasma etching device and an etching method for removing adhesive. By embedding a permanent magnet assembly in an electrode plate, the magnetized surface of the permanent magnet assembly is perpendicular to the plane of the electrode plate. This ensures that the magnetic field generated between different electrode plates under energized conditions is perpendicular to the alternating electric field generated on the electrode plate. Under the action of the alternating electric field, the reactive gas is ionized into plasma. Through the reasonable arrangement of the magnetic field, the concentration and chemical activity of the plasma increase under the action of the magnetic field, and its diffusion ability and speed are improved, allowing it to penetrate deeper into the interior of micropores with high aspect ratios for reactive etching, thereby improving the etching speed and uniformity of residual adhesive in the pores. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of a plasma etching device provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the internal structure of a plasma etching apparatus for placing a printed circuit board, provided in an embodiment of the present invention.

[0027] Figure 3 A diagram illustrating the interaction between the electric and magnetic fields when a plasma etching device is powered on, provided as an embodiment of the present invention;

[0028] Figure 4 This invention provides a diagram illustrating the movement trajectories of electrons and ions when a plasma etching device is powered on.

[0029] Figure 5 This is a flowchart illustrating the steps of an etching and adhesive removal method provided in an embodiment of the present invention.

[0030] In the diagram: 100, Etching chamber; 1, Etching box; 101, Air inlet; 102, Air extraction port; 21, First electrode plate; 22, Second electrode plate; 3, Permanent magnet assembly; 4, Printed circuit board; 51, First conductive rod; 52, Second conductive rod; 6, Air inlet pipe assembly; 7, Flow meter; 8, Vacuum pump; 9, Air extraction baffle; 10, Pressure gauge; 11, Power supply. Detailed Implementation

[0031] This invention provides a plasma etching apparatus and an etching method for removing adhesive, which improves etching speed and adhesive removal uniformity.

[0032] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1:

[0035] To improve the speed and uniformity of plasma etching for removing adhesive residue, and to address the technical challenge of removing contaminants from holes after drilling in existing plasma etching equipment designed for high aspect ratios and smaller hole diameters on various high-end boards, this paper aims to optimize existing equipment for removing residual adhesive residue from holes using plasma etching.

[0036] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the overall structure of a plasma etching apparatus provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of a plasma etching apparatus provided in an embodiment of the present invention; as shown. Figure 1-3As shown, a plasma etching apparatus includes an etching chamber 1, the interior of which is formed an etching chamber 100. The etching chamber 100 is provided with an inlet 101 for introducing reactive gas and an exhaust port 102 for evacuating a vacuum. The reactive gas can be oxygen or carbon tetrafluoride. A plurality of electrode plates 2 are disposed inside the etching chamber 100. The electrode plates 2 include a first electrode plate 21 and a second electrode plate 22. The first electrode plate 21 and the second electrode plate 22 are parallel to each other and spaced apart. An alternating electric field is generated between the first electrode plate 21 and the second electrode plate 22 when energized. A magnetic field perpendicular to the alternating electric field is provided between the first electrode plate 21 and the second electrode plate 22. A printed circuit board 4 is placed between the first electrode plate 21 and the second electrode plate 22. The printed circuit board 4 is placed between the two electrode plates. Permanent magnet groups 3 are embedded in both the first electrode plate 21 and the second electrode plate 22. The magnetized surface of the permanent magnet group 3 is perpendicular to the plane of the electrode plate 2. When the electrode plate 2 is energized, an alternating electric field and a magnetic field perpendicular to each other are generated between the electrode plates 2. The electric field lines of the alternating electric field are perpendicular to the magnetic field lines of the magnetic field. Under the action of the alternating electric field, the reactive gas is ionized to form plasma. The plasma is an ionized gaseous substance composed of positive and negative ions generated after the atoms and atomic groups that have been deprived of some electrons are ionized. The active components of the plasma include: ions, electrons, atoms, and active groups. The plasma undergoes physical collision and chemical reaction with the polymer residue in the through holes or blind holes of the printed circuit board 4 to remove the residue in the surface holes.

[0037] By applying a magnetic field perpendicular to the alternating electric field, the plasma ionization rate of the reactive gas in the etching chamber 100 is increased. Under the influence of the magnetic field, the plasma concentration increases, enhancing its diffusion capacity and speed. This increases the heating rate of plasma bombardment heating during the heating stage. In the etching and desmearing stage, a higher plasma concentration is obtained, which significantly accelerates the chemical reaction of etching and desmearing, allowing for deeper reactive etching into micropores with high aspect ratios, thus increasing the etching speed and production efficiency.

[0038] Working principle: When an electric current is applied to the electrode plate, an alternating electric field is generated. This field ionizes the molecules of the reactant gas into plasma. The active components of the plasma include ions, electrons, atoms, and active particles. By utilizing the properties of these active components, the residual adhesive inside the holes is etched, thereby removing the adhesive. There are two main types of reactions between plasma and the material surface: one is a chemical reaction driven by free radicals, and the other is a physical reaction driven by plasma. Furthermore, plasma is uncharged and highly conductive. When a strong current passes through it, it undergoes violent contraction due to electromagnetic effects, generating temperatures exceeding several million degrees Celsius.

[0039] Electrons in the plasma oscillate uniformly between the two electrode plates, while ions, due to their large mass and small amplitude, do not oscillate violently; relative to the oscillation of electrons, ions can be considered essentially stationary. Under the constraint of this magnetic field, the reciprocating motion of electrons between the electrode plates becomes helical rotation, greatly increasing their travel distance and thus increasing the collision frequency with neutral particles in the plasma, such as... Figure 4 As shown, increasing the plasma density, i.e., increasing the density of active particles, enhances the chemical activity of the plasma, thereby enhancing the chemical reactions of the reactants within the plasma. The increased density of ions with a certain energy enhances the migration ability of their attached atoms on the surface, thus generating surface defects and altering surface chemical properties, promoting surface chemical reactions and diffusion, and increasing the amount of active material diffusing into the borehole. Simultaneously, the plasma's active components generate crystal defects through collisions, adsorb and activate substances, inject high-energy bombardment materials, generate electron discharge sites, and reflect and inject surface particles, all contributing to increased surface and borehole etching rates. Furthermore, the application of a magnetic field to control the plasma's movement improves the uniformity and speed of etching and degumming.

[0040] Furthermore, such as Figure 2 As shown, based on the plasma etching velocity distribution within the etching chamber 100 under non-magnetic conditions, the etching chamber 100 is divided into a first region and a second region. The magnetic field includes a first magnetic field and a second magnetic field. The first magnetic field is disposed within the first region, and the second magnetic field is disposed within the second region. The plasma density within the first region is greater than the plasma density within the second region, and the magnetism of the first magnetic field is less than the magnetism of the second magnetic field.

[0041] Specifically, the plasma density is high in the first region, which means the plasma erosion rate is fast. Therefore, a group of weakly magnetic permanent magnets 3 is arranged in this region to form a weak magnetic field. The plasma density is relatively low in the second region compared to the first region, which means the plasma erosion rate is slow. Therefore, a group of strongly magnetic permanent magnets 3 is arranged in this region to form a strong magnetic field.

[0042] In a specific embodiment, based on the plasma etching velocity distribution within the etching chamber 100 under no magnetic field conditions, magnets with different magnetic field strengths are selected and combined according to the principle that areas with fast etching velocity have weak magnetic fields and areas with slow etching velocity have strong magnetic fields. Based on the etching velocity distribution of the equipment under no magnetic field conditions, permanent magnet groups 3 with different numbers of rows are arranged, with intervals between different rows of permanent magnet groups 3 ranging from 10 to 150 mm. A smaller number of permanent magnet groups 3 are arranged in areas with fast etching velocity to weaken the magnetic field; more permanent magnet groups 3 are arranged in areas with slow etching velocity to strengthen the magnetic field. Alternatively, when the number of permanent magnet groups 3 is uniform, permanent magnets with different magnetic field strengths can be selected and combined. Permanent magnet groups 3 with slightly weaker magnetic field strength are used in areas with fast etching velocity, while permanent magnet groups 3 with stronger magnetic field strength are used in areas with slow etching velocity. The distribution of magnetic field strength compensates for the differences in etching uniformity caused by the gas flow field.

[0043] By using different permanent magnets to increase the magnetic field strength, the plasma ionization effect of the gas is improved, the concentration of active substances is increased, and the production efficiency is improved, while the gas consumption is reduced and the production cost is lowered.

[0044] Furthermore, the first electrode plate 21 and the second electrode plate 22 are respectively provided with a plurality of mounting slots in parallel, and a permanent magnet assembly 3 for generating a magnetic field perpendicular to the alternating electric field is installed in the mounting slots.

[0045] Specifically, the strength of the magnetic field is arranged according to the needs, and according to the size of the electrode plate, several rows of permanent magnet groups 3 with different numbers and / or different strengths are arranged along the plane of the electrode plate, with a spacing of 10mm to 150mm between each row of permanent magnet groups 3, so as to control and adjust the strength of the magnetic field.

[0046] like Figure 1 As shown, permanent magnets of appropriate grades are selected as needed to form permanent magnet group 3. The permanent magnet group 3 is embedded in the electrode plate in the plane direction of the electrode plate and according to the size of the electrode plate.

[0047] Furthermore, such as Figure 2 As shown, the permanent magnet group 3 includes a single permanent magnet or multiple permanent magnet blocks with the same magnetic pole orientation.

[0048] Specifically, the permanent magnet group 3 can be a single permanent magnet or a combination of multiple permanent magnet blocks with the same magnetic pole orientation. The permanent magnet group 3 in the same row can be composed of a single or multiple small permanent magnet blocks with the same magnetic pole orientation. The permanent magnet can be neodymium iron boron, samarium cobalt, or ferrite.

[0049] Furthermore, it also includes a first conductive rod 51, a second conductive rod 52, and a power supply 11. The positive terminal of the power supply 11 is connected to the first electrode plate 21 through the first conductive rod 51, and the negative terminal of the power supply 11 is connected to the second electrode plate 22 through the second conductive rod 52. In a specific embodiment, such as... Figure 1 and Figure 2 As shown, a first conductive rod 51 and a second conductive rod 52 are arranged in the etching chamber 100. Each first conductive rod 51 is connected to multiple first electrode plates 21, and each second conductive rod 52 is connected to multiple second electrode plates 22. The first conductive rod 51 is connected to a power supply 11, which supplies power to the first conductive rod 51 and the second conductive rod 52. The first conductive rod 51 and the second conductive rod 52 apply power to the first electrode plates 21 and the second electrode plates 22, respectively. The power supply 11 is used to supply power to the electrode plates and ionize the reactive gas to generate plasma.

[0050] Furthermore, an air inlet pipe assembly 6 is provided inside the etching chamber 1, and the air inlet pipe assembly 6 is connected to an air supply device; a flow meter 7 is connected to the air inlet 101 of the air inlet pipe assembly 6, and the flow meter 7 is used to monitor the gas flow rate flowing into the etching chamber 100 from the air inlet 101.

[0051] In a specific embodiment, an air inlet pipe group 6 is provided on the top of the etching chamber 1. The air inlet pipe group 6 is connected to an air supply device. A flow meter 7 is connected to the air inlet 101 of the air inlet pipe group 6. The flow meter 7 monitors the flow rate of the reaction gas flowing into the etching chamber 100 from the air inlet 101 and automatically adjusts the flow rate of the reaction gas according to the etching situation to meet the etching requirements.

[0052] Furthermore, an exhaust port 102 is provided at the bottom of the etching chamber 1, and the etching chamber 1 is connected to a vacuum pump 8 through the exhaust port 102. An exhaust baffle 9 is provided inside the etching chamber 1 near the exhaust port 102. The exhaust baffle 9 has a structure to assist in the uniform discharge of residual etching gas, so that the residual etching gas can be discharged evenly. Its structure is not limited. When the residual etching gas passes through the exhaust baffle 9, it enters the exhaust port 102 and is drawn away and discharged by the vacuum pump 8.

[0053] In a specific embodiment, an exhaust port 102 is provided at the bottom of the etching chamber 1. A vacuum pump 8 is used to evacuate the etching chamber 1, so that the air pressure inside the etching chamber 100 reaches the required vacuum pressure value. An exhaust baffle 9 is provided inside the exhaust port 102, which can isolate plasma leakage.

[0054] Furthermore, a pressure gauge 10 is provided on the side of the etching chamber 1, and the pressure gauge 10 is connected to the etching chamber 100 to detect the pressure inside the etching chamber 100.

[0055] In a specific embodiment, the pressure value inside the etching chamber 100 is detected in real time by the pressure gauge 10, and the pressure value inside the etching chamber 100 is controlled and adjusted to reach the required vacuum pressure value.

[0056] In summary, this invention provides a plasma etching apparatus. By embedding a permanent magnet assembly 3 within an electrode plate, with the magnetized surface of the permanent magnet assembly 3 perpendicular to the plane of the electrode plate 2, the magnetic field generated between different electrode plates 2 under energized conditions is perpendicular to the alternating electric field generated on the electrode plate 2. Under the influence of the alternating electric field, the reactive gas is ionized into plasma. Through a rational arrangement of the magnetic field, the concentration and chemical activity of the plasma increase, enhancing its diffusion capacity and speed, allowing it to penetrate deeper into micropores with high aspect ratios for reactive etching. This improves the etching speed and uniformity of residual adhesive within the pores. Furthermore, the magnetic field of the permanent magnet assembly 3 offers a more flexible arrangement. Depending on the difference in etching rates in different areas without a magnetic field, different numbers and magnetic field strengths of permanent magnets can be combined, using strong magnets in areas with slow etching rates and weak magnets in areas with fast etching rates, thus improving the uniformity of adhesive removal.

[0057] Example 2:

[0058] An etching method for removing resist is provided, using the aforementioned plasma etching equipment, comprising the following steps:

[0059] Step S101: Place the printed circuit board 4 to be de-adhesive removed in the etching chamber 100;

[0060] Step S102: Make the pressure inside the etching chamber 100 reach a preset pressure value;

[0061] Specifically, the printed circuit board 4 is first placed into the etching chamber 100, the chamber door is closed, and the vacuum pump 8 is turned on to evacuate the etching chamber 100 through the air extraction port, so that the pressure inside the etching chamber 100 reaches the preset vacuum pressure value.

[0062] Step S103: A first mixed reaction gas is introduced into the etching chamber 100, so that the first electrode plate 21 and the second electrode plate 22 are energized to generate an alternating electric field perpendicular to the magnetic field. The molecules in the first mixed reaction gas are ionized under the action of the alternating electric field and the magnetic field to form a first plasma, which bombards the printed circuit board 4 to make the temperature of the printed circuit board 4 reach a preset temperature value.

[0063] Specifically, a fixed amount of first mixed reactive gas is introduced through the air intake pipe assembly 6, and the flow rate of the first mixed reactive gas is monitored by the flow meter 7 to ensure that it reaches a preset amount. Then, the power supply 11 is turned on to supply power to the electrode plate through the conductive rod, generating an alternating electric field to ionize the first mixed reactive gas and generate the first plasma. The active substances in the first plasma include electrons, ions, atoms, and active particles. Electrons are subjected to intense oscillations by the alternating electric field, bombarding the printed circuit board 4 and heating it to the required temperature. Under the action of the magnetic field, the electron movement path becomes longer, and the probability of collision with other particles increases significantly, greatly improving the collision ionization rate. After more electrons and ions are ionized, the number of charged particles bombarding the circuit board increases, and more kinetic energy is converted into heat energy, resulting in a faster heating rate of the printed circuit board 4, which helps to remove the adhesive.

[0064] Step S104: Control the introduction of a second mixed reaction gas into the etching chamber 100. The molecules of the second mixed reaction gas are ionized under the action of the alternating electric field and magnetic field to form a second plasma, which then etches away the residual adhesive on the printed circuit board 4.

[0065] Specifically, after the etching chamber is heated to 100°C, the flow meter 7 is monitored to introduce a fixed amount of second mixed reaction gas, such as a fixed amount of oxygen and carbon tetrafluoride gas. The active substances generated after the molecules of the second mixed reaction gas are ionized react chemically with the residual adhesive after drilling, thus etching away the adhesive. Under the action of the magnetic field, the ionization rate of the gas molecules is increased, resulting in a higher concentration of chemically reactive substances, which accelerates the chemical reaction rate. At the same time, the increased concentration also increases the driving force for the chemical substances to diffuse into the deep holes, which helps to improve the adhesive removal capacity in high aspect ratio micropores.

[0066] It is worth noting that the first mixed reaction gas includes oxygen and nitrogen; the second mixed reaction gas includes oxygen and carbon tetrafluoride gas. Argon and / or nitrogen may also be added to the second mixed reaction gas to enhance the reaction activity.

[0067] In summary, the embodiments of the present invention provide an etching method for removing adhesive residue. Using an etching chamber 1 with a magnetic field perpendicular to the alternating electric field, the application of a magnetic field perpendicular to the electric field increases the plasma ionization rate, thereby increasing the heating rate of plasma bombardment heating during the heating stage. During the etching and adhesive removal stage, a higher concentration of active reactive substances is obtained, which significantly accelerates the chemical reaction of etching and adhesive removal, increases the etching speed, and thus improves the etching speed and uniformity of residual adhesive residue in the hole.

[0068] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plasma etching apparatus, characterized by, The etching box is internally formed with an etching chamber; the etching chamber is provided with a gas inlet for filling reaction gas and a gas outlet for vacuumizing; a plurality of first electrode plates and second electrode plates are arranged in the etching chamber, the first electrode plates and the second electrode plates are arranged in parallel and are spaced apart, an alternating electric field is generated between the first electrode plates and the second electrode plates in an energized state, and a magnetic field perpendicular to the alternating electric field is arranged between the first electrode plates and the second electrode plates; The etching chamber is divided into a first region and a second region, the magnetic field includes a first magnetic field and a second magnetic field, the first magnetic field is arranged in the first region, and the second magnetic field is arranged in the second region; The plasma density in the first region is greater than the plasma density in the second region, and the magnetism of the first magnetic field is less than the magnetism of the second magnetic field; A plurality of mounting grooves are arranged in parallel on the first electrode plates and the second electrode plates, and a permanent magnet group for generating a magnetic field perpendicular to the alternating electric field is mounted in the mounting grooves.

2. The plasma etching apparatus of claim 1, wherein, The permanent magnet groups in each column are spaced apart by 10mm-150mm.

3. The plasma etching apparatus of claim 1, wherein, A first conductive rod, a second conductive rod and a power supply are further included, the positive pole of the power supply is connected with the first electrode plates through the first conductive rod, and the negative pole of the power supply is connected with the second electrode plates through the second conductive rod.

4. The plasma etching apparatus of claim 1, wherein, An air inlet pipeline group is arranged in the etching box, the air inlet pipeline group is connected with a gas supply device, a flow meter is connected at the air inlet of the air inlet pipeline group, and the flow meter is used for monitoring the gas flow rate flowing into the etching chamber from the air inlet.

5. The plasma etching apparatus of claim 1, wherein, An air outlet is arranged at the bottom of the etching box, and an air baffle is arranged on the inner side of the etching box close to the air outlet.

6. The plasma etching apparatus of claim 5, wherein, A pressure gauge is arranged on the side of the etching box, the pressure gauge is connected in the etching chamber, and is used for detecting the real-time pressure in the etching chamber.

7. An etch resist removal method characterized by, The plasma etching equipment according to any one of claims 1-6 is used, and the following steps are included: A printed circuit board to be desmear is placed in the etching chamber; The pressure in the etching chamber is made to reach a preset pressure value; A first mixed reaction gas is introduced into the etching chamber, the first electrode plates and the second electrode plates are energized to generate an alternating electric field perpendicular to the magnetic field, and after molecules in the first mixed reaction gas are ionized to form a first plasma under the action of the alternating electric field and the magnetic field, the printed circuit board is bombarded to make the temperature of the printed circuit board reach a preset temperature value; A second mixed reaction gas is introduced into the etching chamber, and after molecules in the second mixed reaction gas are ionized to form a second plasma under the action of the alternating electric field and the magnetic field, the residue on the printed circuit board is etched and removed.

8. The method according to claim 7, wherein The first mixed reaction gas includes oxygen and nitrogen, and the second mixed reaction gas includes oxygen and carbon tetrafluoride gas.

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