CN116581009A - Plasma cleaning module and plasma cleaning method - Google Patents

Abstract

The application relates to the field of plasma etching and discloses a plasma cleaning module and a plasma cleaning method, wherein the plasma cleaning module comprises two gas-discharge assemblies and at least two electrode plates, the electrode plates are sequentially arranged at intervals along one direction, gaps are reserved between the two adjacent electrode plates, the two gas-discharge assemblies are used for relatively spraying gas to be ionized into the gaps, an alternating electric field is generated when the two adjacent electrode plates are electrified, a magnetic field intersecting with the alternating electric field is arranged in the gaps, and electrons are changed into spiral rotary motion from reciprocating motion under the combined action of the alternating electric field and the magnetic field, so that the travel of the electrons is increased, the collision frequency of the electrons and neutral particles is increased, the density of active particles is increased, the power of active particles for diffusing into deep holes is improved, the migration capability of the active particles is enhanced, the chemical reaction of reactive substances in plasma is enhanced, and the promotion of the biting rate and uniformity of the surfaces and the holes of a circuit board is promoted.

Description

Plasma cleaning module and plasma cleaning method

Technical Field

The application relates to the technical field of plasma etching, in particular to a plasma cleaning module and a plasma cleaning method.

Background

In the fabrication of printed circuit boards, particularly high density interconnect circuit boards, after laser machining blind vias or mechanical drilling of through holes, a hole metallization process is required to electrically connect the layers of the printed circuit board through the metallized holes. However, the laser holes or mechanical holes often have residual colloidal material attached to the holes after drilling because of the high temperatures locally present during drilling, and the colloidal material in the holes must be removed prior to the metallization process in order to prevent quality problems in the subsequent metallization process.

At present, the plasma cleaning equipment is used for removing residual glue in holes, which is the most common means in the industry, and the principle is that after a cavity provided with a circuit board is vacuumized, mixed gas of oxygen and carbon tetrafluoride is introduced, and a high-voltage alternating electric field with high frequency conversion is applied to electrode plates positioned at two sides of the circuit board, so that the mixed gas generates active plasmas, and the cleaned circuit board is bombarded under the dual actions of physics and chemistry to remove the residual glue on the surface and in the holes of the circuit board, and finally, the purpose of cleaning the circuit board is achieved.

However, with the rapid development of the electronics industry in recent years, from 5G communication, AI artificial intelligence, telecommunications, military, aviation and aerospace, medical, etc., the ever-increasing functions and demands are driving the demand for complex high-performance circuit boards, resulting in high-density multi-layer board structures, high TG hard boards ranging from 4 layers to 48 layers or more, double-sided PTFE, mixed-pressure PTFE multi-layer boards and ceramic resin composite substrates, multi-layer flexible boards and rigid-flex boards, etc. These high end plate structures seek high aspect ratios and smaller pore sizes, and impurities in the drilled holes are also more difficult to remove; in addition, some 5G circuit board products have the characteristic of large jointed board size, and the single board size of the circuit board reaches more than 685.8mm, so that the plasma machine with a large cavity starts to be gradually applied in order to improve the productivity of removing glue residues by plasma, but the uniformity of removing glue cannot be improved by the large cavity.

In order to improve the biting and removing rate, measures are taken in the industry, such as improving the removing rate by improving the power of the electrode, increasing the gas flow or the cavity temperature and other technological means, and although the technological means have certain effects, the production cost is obviously increased, after the production cost exceeds a certain value, the improvement of the glue-removing speed is not obvious, and even the condition of burning out the circuit board is possibly generated. In order to improve the uniformity of plasma etching and photoresist removal, the current basic thought is to change the distribution of a gas flow field, such as optimizing the layout of an air inlet pipeline, adjusting the opening size of an air outlet baffle, and opening a feeding electrode or a hanging rack, and the like, and although the method has a certain effect, along with the increase of a cavity, the method for changing the gas flow field is difficult to meet the higher requirements of the etching and photoresist removal speed and uniformity.

The above information is presented as background information only to aid in the understanding of the present disclosure and is not intended or admitted to be prior art relative to the present disclosure.

Disclosure of Invention

The application aims to provide a plasma cleaning module and a plasma cleaning method, which mainly solve the technical problems of slower cleaning speed and poorer cleaning uniformity of the existing plasma cleaning equipment.

To achieve the purpose, the application adopts the following technical scheme:

the utility model provides a plasma cleaning module, includes two gas row subassemblies and sets up two at least two electrode plates between the gas row subassembly, a plurality of the electrode plates are along a direction interval arrangement in proper order, and adjacent two all have between the electrode plate and be used for supplying the clearance that waits to wash the circuit board to place, two gas row subassemblies are used for to treat the ionization gas in the clearance sprays relatively, adjacent two the electrode plate produces when the circular telegram is used for treating the ionization gas ionization alternating electric field of plasma, be provided with in the clearance with the perpendicular crossing magnetic field of alternating electric field's electric field line.

In one embodiment, the gap includes 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 in the first region, and the second magnetic field is disposed in the second region;

the plasma density in the first region is greater than the plasma density in the second region, and the magnetic properties of the first magnetic field are less than the magnetic properties of the second magnetic field.

In one embodiment, the electrode plate is provided with a mounting groove, and a permanent magnet group for generating a magnetic field perpendicular to the alternating electric field is mounted in the mounting groove.

In one embodiment, the electrode plate is provided with a plurality of rows of mounting grooves, the permanent magnet groups are arranged in the plurality of rows of mounting grooves, and the interval between the permanent magnet groups in each row is 10 mm-150 mm.

In one embodiment, the gas exhaust assembly comprises a communicating pipe and a plurality of gas outlet pipes respectively connected with the communicating pipe, the communicating pipe is communicated with the gas outlet pipes and used for providing gas to be ionized for the gas outlet pipes, and the gas outlet pipes extend along the length direction of the electrode plates and are used for allowing the gas to be ionized to enter the gaps.

In one embodiment, the air inlet direction of the air outlet pipe in one air exhaust assembly is opposite to the air inlet direction of the air outlet pipe in the other air exhaust assembly.

In one embodiment, the air outlet pipe comprises an inner layer pipe and an outer layer pipe sleeved on the periphery of the inner layer pipe, a buffer chamber is arranged between the outer wall of the inner layer pipe and the inner wall of the outer layer pipe, the inner layer pipe is provided with an air inlet channel communicated with the inside of the communicating pipe, vent holes respectively communicated with the air inlet channel and the buffer chamber are formed in the pipe wall of the inner layer pipe, and a plurality of air outlet holes communicated with the buffer chamber are formed in the pipe wall of the outer layer pipe, which is opposite to the gap.

In one embodiment, each of the two gas discharge assemblies is connected to a regulating valve, and the regulating valves are used for regulating the flow rate of the gas to be ionized sprayed by the gas discharge assemblies.

In one embodiment, the electrode plate is internally provided with a bidirectional waterway, the bidirectional waterway comprises a water inlet channel and a water outlet channel, the water inlet channel is provided with a liquid inlet for cooling liquid to enter, the water outlet channel is provided with a liquid outlet for cooling liquid to be discharged outwards, the liquid inlet and the liquid outlet are adjacently arranged, one end of the water inlet channel away from the liquid inlet and one end of the water outlet channel away from the liquid outlet are mutually communicated, and the water outlet channel is folded back to the liquid outlet along the extending path of the water inlet channel.

In one embodiment, the extending path of the water inlet channel comprises a plurality of first wave crests and a plurality of first wave troughs, and the water inlet channel alternately and curvingly extends between the first wave crests and the first wave troughs;

the extending path of the water outlet channel comprises a plurality of second wave crests and a plurality of second wave troughs, the water outlet channel alternately and zigzag extends at the second wave crests and the second wave troughs, each second wave crest and a corresponding first wave crest are adjacently arranged, and each second wave trough and a corresponding first wave trough are adjacently arranged.

The application also provides a plasma cleaning method, which uses the plasma cleaning module, and comprises the following steps:

placing a circuit board to be cleaned in a gap between two adjacent electrode plates;

enabling the pressure in the gap to reach a preset vacuum pressure value;

the gas exhaust assembly is used for introducing quantitative first gas into the gap, alternating current is introduced into each electrode plate, so that an alternating electric field which is mutually perpendicular to the magnetic field is generated at the gap between two adjacent electrode plates, the first gas is ionized under the combined action of the alternating electric field and the magnetic field to form first plasma, and then bombards the circuit board to be cleaned, so that the temperature of the circuit board to be cleaned reaches a preset temperature value;

and the gas exhaust assembly is used for introducing quantitative second gas into the gap, molecules of the second gas are ionized under the combined action of an alternating electric field and a magnetic field to form second plasmas, and the surfaces and the holes of the circuit board to be cleaned are etched by the second plasmas so as to remove impurities on the surfaces and in the holes of the circuit board to be cleaned.

Compared with the prior art, the plasma cleaning module provided by the application has at least the following beneficial effects:

when the device works, the gas exhaust component sprays gas to be ionized into each gap, simultaneously alternating current is supplied to each electrode plate, an alternating electric field is generated in the gap between two adjacent electrode plates, the alternating electric field can ionize the gas to be ionized into plasma, the plasma is an ionized gaseous substance composed of positive and negative ions generated after atoms and atomic groups of which partial electrons are deprived are ionized, and the active components of the plasma comprise: ions, electrons, atoms and active particles, wherein electrons make integral oscillation between two electrode plates, and ions do not violently oscillate due to the fact that the mass is large and the amplitude of the ions is small, and the ions are basically motionless relative to the oscillation of the electrons. Under the combined action of the alternating electric field and the magnetic field, electrons are changed into spiral rotary motion from reciprocating motion at a gap between the electrode plates, so that the stroke of the electrons is increased, the collision frequency of the electrons and neutral particles is increased, the density of active particles is increased, the quantity of active substances diffused into holes is increased, namely, the chemical reaction of reactive substances in plasmas is enhanced, meanwhile, the concentration of the active particles is increased, the power of the active particles diffusing into deep holes is improved, the migration capability of the active particles on the surface of a circuit board and in the holes is enhanced, the promotion of the biting rate of the surface of the circuit board and in the holes is promoted, and the residual glue on the surface of the circuit board and in the holes is removed more efficiently and uniformly. In addition, the two gas-exhaust assemblies are arranged to jet the gas to be ionized to the gap between the two adjacent electrode plates relatively, so that the gas distribution in the gap between the two electrode plates is more uniform, the distribution of active plasmas in the gap between the two adjacent electrode plates is also more uniform, and the uniformity of the cleaning circuit board is further improved.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a plasma cleaning module and a material frame combined according to a first embodiment of the present application;

FIG. 2 is a front view of a plasma cleaning module and a frame according to a first embodiment of the present application;

FIG. 3 is a cross-sectional view at A-A in FIG. 2;

FIG. 4 is a schematic diagram of the distribution of alternating electric field and magnetic field of an electrode plate after alternating current is applied according to the first embodiment of the present application;

FIG. 5 is a diagram showing the motion trajectories of electrons and ions under the combined action of an alternating electric field and a magnetic field in the first embodiment of the present application;

FIG. 6 is a schematic structural diagram of two gas-exhaust assemblies according to a first embodiment of the present application;

FIG. 7 is a side view of an outlet duct according to a first embodiment of the present application;

FIG. 8 is an enlarged view of a portion of FIG. 7 at A;

FIG. 9 is a cross-sectional view of an outlet duct according to a first embodiment of the present application;

fig. 10 is a schematic diagram of a bidirectional waterway in an electrode plate according to an embodiment of the present application.

Wherein, each reference sign in the figure:

201. an air exhaust assembly; 2011. a communicating pipe; 20111. an air inlet; 2012. an air outlet pipe; 20121. an inner layer tube; 201211, intake passage; 201212 and vent holes; 20122. an outer layer tube; 201221 and an air outlet; 20123. a buffer chamber; 202. an electrode plate; 2021. a mounting groove; 2022. a permanent magnet group; 2023. a two-way waterway; 20231. a liquid inlet; 20232. a liquid outlet; 20233. a water inlet channel; 202331, first peak; 202332, first trough; 20234. a water outlet channel; 202341, second peak; 202342, second trough; 203. a gap; 2031. a first cleaning region; 2032. a second cleaning region;

30. a material frame; 100. a circuit board.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "upper," "lower," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship based on that shown in the drawings, merely to facilitate describing the present application and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent.

Example 1

The embodiment provides a plasma cleaning module, which can be applied to plasma cleaning equipment.

Referring to fig. 1 to 4, the plasma cleaning module specifically includes two gas line assemblies 201 and at least two electrode plates 202 sequentially arranged at intervals along a direction, wherein a plurality of electrode plates 202 are arranged between the two gas line assemblies 201 and parallel to each other, and a gap 203 is formed between two adjacent electrode plates 202.

The gap 203 is used for placing the circuit board 100 to be cleaned, in one embodiment, the plasma cleaning module further includes a material frame 30, where the material frame 30 includes a plurality of circuit board mounting positions, and the circuit board mounting positions are spaced from the electrode plates 202, and the circuit board 100 to be cleaned is fixed in the circuit board mounting positions.

Wherein, two gas-exhaust assemblies 201 are used for relatively spraying gas to be ionized into the gap 203, when the two adjacent electrode plates 202 are electrified, an alternating electric field for ionizing the gas to be ionized into plasma is generated, and a magnetic field which is perpendicularly intersected with the electric field line of the alternating electric field is arranged in the gap 203.

The present embodiment is mainly used for removing the residual glue on the surface or in the hole of the circuit board 100, so the gas to be ionized is preferably a mixed gas of oxygen and carbon tetrafluoride.

Referring to fig. 1 and fig. 3 to fig. 5, in one embodiment, a plurality of rows of mounting grooves 2021 are disposed in the electrode plate 202, at least one permanent magnet set 2022 is disposed in each mounting groove 2021, and the magnetizing surface of the permanent magnet set 2022 and the electrode plate 202 are parallel to each other, so that a magnetic field perpendicular to the electric field lines of the alternating electric field is generated in the gap 203. Specifically, the interval between the permanent magnet groups 2022 of each row may be 10mm to 150mm.

In operation, the gas exhaust assembly 201 sprays gas to be ionized into each gap 203, simultaneously, alternating current is supplied to each electrode plate 202, an alternating electric field is generated in the gap 203 between two adjacent electrode plates 202, the alternating electric field can ionize the gas to be ionized into plasma, the plasma is an ionized gaseous substance composed of positive and negative ions generated after atoms and atomic groups of which partial electrons are deprived are ionized, and active components of the plasma comprise: ions, electrons, atoms and active particles, wherein electrons oscillate integrally between the two electrode plates 202, and ions do not oscillate strongly due to the large mass and small amplitude of the ions, and the ions are substantially stationary with respect to the oscillation of the electrons. Under the combined action of the alternating electric field and the magnetic field, electrons are changed from reciprocating motion to spiral rotation motion at the gap 203 between the electrode plates 202, so that the stroke of the electrons is increased, the collision frequency of the electrons and neutral particles is increased, the density of active particles is increased, the quantity of active substances diffused into holes is increased, namely, the chemical reaction of reactive substances in plasmas is enhanced, meanwhile, the concentration of the active particles is increased, the power of the active particles diffusing into deep holes is improved, the migration capability of the active particles on the surface of the circuit board 100 and in the holes is enhanced, the promotion of the biting rate of the active particles on the surface of the circuit board 100 and in the holes is promoted, and the residual glue on the surface of the circuit board 100 and in the holes is removed more efficiently and uniformly.

Further, since the two gas-exhaust assemblies 201 are provided in this embodiment, and the two gas-exhaust assemblies 201 are configured to relatively inject the gas to be ionized into the gap 203 between the two adjacent electrode plates 202, the gas in the gap 203 between the two electrode plates 202 is more uniformly distributed in the Z-axis direction, so that the plasma in the gap 203 between the two adjacent electrode plates 202 is also more uniformly distributed in the Z-axis direction, and further, the uniformity of the cleaning circuit board 100 is further improved. In addition, the two gas-exhaust assemblies 201 can be respectively connected with a regulating valve (not shown in the figure), and the gas-exhaust flow of the two gas-exhaust assemblies 201 can be controlled through the regulating valve, so that the ratio of the gas-exhaust assemblies 201 to the gas filled into the gaps 203 is controlled, and the cleaning uniformity is better controlled.

Furthermore, according to the distribution of the plasma etching speed in the gap 203 under the condition of no magnetic field, a magnetic field with relatively weak magnetism can be arranged in a region with relatively fast etching speed, a magnetic field with relatively strong magnetism can be arranged in a region with relatively slow etching speed, and the difference of the etching uniformity caused by the gas flow field in the gap 203 can be compensated by the strong and weak distribution of the magnetic field. For example, when the gap 203 is divided into a first region and a second region, and the plasma density in the first region is greater than that in the second region, the magnetic field is divided into a first magnetic field disposed in the first region and a second magnetic field disposed in the second region, and the magnetism of the first magnetic field is designed to be smaller than that of the second magnetic field. Specifically, the plasma density in the first region is large, that is, the plasma etching speed in the first region is high, so that the permanent magnet group 2022 having weak magnetism or small number is arranged in the region to form a weak magnetic field; the plasma density in the second region is small relative to the plasma density in the first region, that is, the plasma etching speed in the second region is slow, so that the permanent magnet group 2022 having strong magnetism or a large number is arranged in the second region to form a strong magnetic field.

It should be noted that, referring to fig. 1 and 3, the permanent magnet set 2022 may be a whole permanent magnet or permanent magnet blocks with multiple magnetic poles facing the same direction. The permanent magnet may be neodymium iron boron, samarium cobalt or ferrite.

Referring to fig. 3 and fig. 6 to fig. 8 together, the gas exhaust assembly 201 specifically includes a communicating pipe 2011 and a plurality of gas outlet pipes 2012, at least a portion of the communicating pipe 2011 and the plurality of gas outlet pipes 2012 are all accommodated in the etching chamber 101, the communicating pipe 2011 is used for communicating the plurality of gas outlet pipes 2012, a gas inlet 20111 is disposed on the communicating pipe 2011, external gas to be ionized can enter into each gas outlet pipe 2012 from the gas inlet 20111, in this embodiment, one gas outlet pipe 2012 faces one gap 203, and the gas outlet pipes 2012 extend along the length direction (i.e. the positive direction or the negative direction of the X axis in fig. 1) of the electrode plate 202, and the gas outlet pipes 2012 are used for allowing the gas to be ionized to enter into the corresponding gaps 203.

Referring to fig. 3 and fig. 6 to fig. 8 again, the air inlet direction of each air outlet pipe 2012 in one air exhaust assembly 201 is opposite to the air inlet direction of each air outlet pipe 2012 in the other air exhaust assembly 201, which is specifically understood that the air inlet direction of each air outlet pipe 2012 in one air exhaust assembly 201 is directed in the positive direction of the X-axis in fig. 1, and the air inlet direction of each air outlet pipe 2012 in the other air exhaust assembly 201 is directed in the opposite direction of the X-axis in fig. 1, so that the gas to be ionized in the gap 203 is distributed more uniformly in the direction of the X-axis by the mutual superposition of the gases injected by the two air exhaust assemblies 201, so that the active plasma in the gap 203 is distributed more uniformly in the direction of the X-axis, and the uniformity of the cleaning circuit board 100 is further improved.

Referring to fig. 7 and 8 together, the air outlet pipe 2012 specifically includes an inner pipe 20121 and an outer pipe 20122, the outer pipe 20122 is sleeved on the outer periphery of the inner pipe 20121, a buffer chamber 20123 is disposed between the inner wall of the outer pipe 20122 and the outer wall of the inner pipe 20121, an air inlet channel 201211 is disposed in the inner pipe 20121, the air inlet channel 201211 and an air inlet 20111 of the communicating pipe 2011 are mutually communicated, a plurality of air holes 201212 are formed in the pipe wall of the inner pipe 20121, one end of the air hole 201212 is communicated with the buffer chamber 20123, the other end of the air hole 201212 is communicated with the air inlet channel 201211, the air inlet channel 201211 is communicated with the buffer chamber 20123 through an air hole 201212, and a plurality of air outlet holes 201221 are formed in the pipe wall of the outer pipe 20122, and the air outlet holes 201221 are communicated with the buffer chamber 20123 and face a corresponding gap 203. In operation, the external gas to be ionized can enter the air inlet channels 201211 of the air outlet pipes 2012 from the air inlet 20111, then enter the buffer chamber 20123 through the air holes 201212, and after the buffer chamber 20123 is almost filled, the gas in the buffer chamber 20123 overflows from the air outlet holes 201221 and enters the corresponding gap 203. Through designing the air outlet pipe 2012 into a double-layer pipeline structure, the gas to be ionized can be more uniformly supplied into the gap 203 in the X-axis direction, so that the ventilation uniformity is further improved, and the uniformity of the cleaning circuit board 100 is further improved.

Referring to fig. 9, two air discharge holes 201221 are formed in the wall of the outer tube 20122, and the two air discharge holes 201221 extend along the length direction of the electrode plate 202 (i.e. the positive direction or the negative direction of the X-axis in fig. 1), and the air discharge directions of the two air discharge holes 201221 are inclined. Specifically, referring to fig. 4, when the circuit board 100 is placed at the gap 203, the circuit board 100 divides the gap 203 into a first cleaning area 2031 and a second cleaning area 2032, wherein the air outlet direction of one row of inclined air outlet holes 201221 is directed to the first cleaning area 2031, and the air outlet direction of the other row of inclined air outlet holes 201221 is directed to the second cleaning area 2032, so that the gas to be ionized is uniformly introduced into both the first cleaning area 2031 and the second cleaning area 2032, and the cleaning efficiency of the two surfaces and the holes of the circuit board 100 is improved. More specifically, the angle between the air outlet direction of each air outlet 201221 and the center line of the outer tube 20122 is 5 ° to 20 °, preferably 10 °, and the aperture of each air outlet 201221 is preferably 1.2mm. Further, since the outer diameter of the outer tube 20122 is small, in order to facilitate the processing of the two vent holes 201221, the present embodiment designs the two vent holes 201221 to be offset from each other along the X-axis.

As the electrode plate 202 is electrified to generate heat, in order to prevent the temperature of the electrode plate 202 from being too high, referring to fig. 3 and 10, in this embodiment, a bi-directional water path 2023 is disposed in the electrode plate 202, the bi-directional water path 2023 has a liquid inlet 20231 and a liquid outlet 20232, the liquid inlet 20231 is used for allowing cooling liquid to enter the electrode plate 202, and the liquid outlet 20232 is used for allowing the cooling liquid to be discharged outwards. Specifically, the liquid inlet 20231 and the liquid outlet 20232 are adjacently disposed, and the bidirectional waterway 2023 specifically includes a water inlet 20233 and a water outlet 20234, the liquid inlet 20231 is disposed on the water inlet 20233, the liquid outlet 20232 is disposed on the water outlet 20234, one end of the water inlet 20233 far away from the liquid inlet 20231 and one end of the water outlet 20234 far away from the liquid outlet 20232 are mutually communicated, the water inlet 20233 extends in a meandering manner along the outer sides of the permanent magnet groups 2022, the water outlet 20234 is folded back to the liquid outlet 20232 along the extending path of the water inlet 20233, and heat dissipation of the electrode plate 202 can be more uniform through mutual superposition of the water inlet 20233 and the water outlet 20234, so that the temperature of the electrode plate 202 can be more uniform, the electrode plate 202 can work within a preset temperature range, the plasma distribution in the gap 203 can be more uniform due to the electrode plate 202 with uniform temperature, and the uniformity of the cleaning circuit board can be further improved.

Referring to fig. 3 and fig. 10 again, the extending path of the water inlet 20233 specifically includes a plurality of first peaks 202331 and a plurality of first valleys 202332, and the water inlet 20233 alternately extends in a zigzag manner between the first peaks 202331 and the first valleys 202332, on one hand, the zigzag extending water inlet 20233 can increase the contact area between the water inlet 20233 and the electrode plate 202, so as to further improve the heat dissipation efficiency of the electrode plate 202; on the other hand, the water inlet passage 20233 extending in a meandering manner can avoid the permanent magnet group 2022, and a plurality of rows of permanent magnet groups 2022 can be mounted on the electrode plate 202. Correspondingly, the extending path of the water outlet channel 20234 includes a plurality of second peaks 202341 and a plurality of second troughs 202342, the water outlet channel 20234 alternately extends in a zigzag manner between the second peaks 202341 and the second troughs 202342, each second peak 202341 is arranged adjacent to a corresponding first peak 202331, and the second trough 202342 is arranged adjacent to a corresponding first trough 202332, so that the water outlet channel 20234 is designed, and on the premise of improving the heat dissipation efficiency of the electrode plate 202, the temperature of each part of the water outlet channel 20234 and the water inlet channel 20233 after being mutually overlapped can be further ensured to be approximately the same, so that the temperature of the electrode plate 202 is more uniform.

In summary, the plasma cleaning module of the technical scheme improves the efficiency and uniformity of plasma cleaning by arranging the magnetic field vertically intersecting with the alternating electric field; according to the technical scheme, the uniformity of the distribution of the gas field in the gap 203 on the Z axis is improved by arranging the two gas exhaust assemblies 201 which are oppositely sprayed, so that the uniformity of plasma cleaning is further improved; in the technical scheme, the air inlet directions of the two air exhaust assemblies 201 are designed to be opposite, and the air outlet of each air exhaust assembly 201 has a buffer effect, so that the uniformity of the distribution of the air field in the gap 203 on the X axis is improved, and the uniformity of plasma cleaning is further improved; the temperature of the electrode plate 202 is more uniform by arranging the bidirectional waterway 2023, so that the electric field intensity in the gap 203 is more uniform, the plasma in the gap 203 is more uniform, the uniformity of the cleaning circuit board is further improved, and the purpose that the surface of the multilayer circuit board and the residual glue in the holes can be cleaned efficiently and very uniformly is finally realized.

Example two

The present embodiment provides a plasma cleaning method, referring to fig. 1 to 4, the plasma cleaning method includes the following steps:

step S1: placing the circuit board 100 to be cleaned into the gap 203 between the two adjacent electrode plates 202;

step S2: the pressure in the gap 203 reaches a preset vacuum pressure value in a vacuumizing mode;

step S3: the gas exhaust assembly 201 introduces a certain amount of first gas (the first gas in this embodiment is preferably a mixed gas of oxygen and nitrogen) into the gap 203, and introduces alternating current into each electrode plate 202, so that an alternating electric field perpendicular to the magnetic field is generated at the gap 203 between two adjacent electrode plates 202, the first gas is ionized under the combined action of the alternating electric field and the magnetic field to form first plasma, and the first plasma bombards the circuit board 100 to be cleaned, so that the temperature of the circuit board 100 to be cleaned reaches a preset temperature value;

specifically, under the combined action of the alternating electric field and the magnetic field, electrons are changed from reciprocating motion to spiral rotation motion at the gap 203 between the electrode plates 202, the motion path of the electrons is prolonged, the collision probability of the electrons and other particles is remarkably increased, so that the ionization rate is greatly increased, the number of charged particles bombarding the circuit board 100 is increased, more kinetic energy is converted into heat energy, the temperature rising speed of the circuit board 100 is greatly accelerated, and the glue removal is facilitated; in addition, when the temperature of the electrode plate 202 is too high, a cooling liquid can be introduced into the bidirectional waterway 2023, so that the electrode plate 202 works in a proper temperature range;

step S4: the two gas exhaust assemblies 201 relatively introduce a certain amount of second gas (the second gas in this embodiment is preferably a mixed gas of oxygen and carbon tetrafluoride) into the gap 203, and molecules of the second gas are ionized under the combined action of an alternating electric field and a magnetic field to form second plasmas, and the surfaces and the holes of the circuit board 100 to be cleaned are etched by the second plasmas so as to remove impurities on the surfaces and in the holes of the circuit board 100 to be cleaned;

specifically, under the combined action of the alternating electric field and the magnetic field, electrons in the second plasma body change from reciprocating motion to spiral rotation motion at the gap 203 between the electrode plates 202, so that the travel of the electrons is increased, the collision frequency of the electrons and neutral particles is increased, the density of active particles in the second plasma body is increased, the number of active substances diffused into holes is increased, namely, the chemical reaction of reactive substances in the second plasma body is enhanced, meanwhile, the increase of the concentration of the active particles can improve the power of the diffusion of the active particles to deep holes, the migration capability of the active particles on the surface of the circuit board 100 and in the holes is enhanced, the improvement of the biting rate of the surface of the circuit board 100 and in the holes is promoted, and the residual glue on the surface of the circuit board 100 and in the holes is removed more efficiently and uniformly.

In summary, according to the plasma cleaning method provided by the embodiment of the application, as the magnetic field vertically intersecting with the electric field is applied, the ionization rate of plasma is improved, and the heating rate of plasma bombardment heating can be improved in the heating stage; in the stage of etching and photoresist removing, active reaction substances with higher concentration are obtained, so that the chemical reaction of etching and photoresist removing is remarkably accelerated, and the etching speed is improved, thereby improving the etching speed and uniformity of residual photoresist in holes. Since the two gas exhaust assemblies 201 relatively spray the gas to be ionized into the gap 203, the gas to be ionized in the gap 203 is distributed more uniformly, and the uniformity of removing the glue on the surface of the circuit board and in the holes is further improved.

The foregoing description of the preferred embodiments of the present application has been provided for the purpose of illustrating the general principles of the present application and is not to be construed as limiting the scope of the application in any way. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other embodiments of the present application as will occur to those skilled in the art without the exercise of inventive faculty, are intended to be included within the scope of the present application.

Claims (10)

1. The utility model provides a plasma cleaning module, its characterized in that includes two gas row subassembly (201) and sets up two at least electrode plates (202) between gas row subassembly (201), a plurality of electrode plates (202) follow a direction interval arrangement in proper order, adjacent two between electrode plates (202) all have clearance (203) that are used for supplying the circuit board that waits to wash to place, two gas row subassembly (201) are used for to spray to waiting to ionize gas relatively in clearance (203), adjacent two electrode plates (202) are when the circular telegram produce be used for waiting to ionize gas to ionize the alternating electric field of plasma, be provided with in clearance (203) with the perpendicular crossing magnetic field of electric field line of alternating electric field.

2. The plasma cleaning module of claim 1, wherein the gap (203) comprises a first region and a second region, the magnetic field comprising a first magnetic field and a second magnetic field, the first magnetic field being disposed in the first region and the second magnetic field being disposed in the second region;

the plasma density in the first region is greater than the plasma density in the second region, and the magnetic properties of the first magnetic field are less than the magnetic properties of the second magnetic field.

3. The plasma cleaning module according to claim 1, wherein a mounting groove (2021) is provided on the electrode plate (202), and a permanent magnet group (2022) for generating a magnetic field intersecting the alternating electric field is mounted in the mounting groove (2021).

4. The plasma cleaning module according to claim 1, wherein the gas exhaust assembly (201) comprises a communicating pipe (2011) and a plurality of gas outlet pipes (2012) respectively connected to the communicating pipe (2011), the communicating pipe (2011) communicates with a plurality of the gas outlet pipes (2012) and is used for providing gas to be ionized to the plurality of the gas outlet pipes (2012), and the gas outlet pipes (2012) extend along the length direction of the electrode plate (202) and are used for allowing the gas to be ionized to enter the gap (203).

5. The plasma cleaning module of claim 4, wherein the inlet direction of the outlet pipe (2012) in one of the gas line assemblies (201) is opposite to the inlet direction of the outlet pipe (2012) in the other of the gas line assemblies (201).

6. The plasma cleaning module according to claim 4, wherein the gas outlet pipe (2012) comprises an inner layer pipe (20121) and an outer layer pipe (20122) sleeved on the periphery of the inner layer pipe (20121), a buffer chamber (20123) is arranged between the outer wall of the inner layer pipe (20121) and the inner wall of the outer layer pipe (20122), the inner layer pipe (20121) is provided with an air inlet channel (201211) communicated with the inside of the communicating pipe (2011), the pipe wall of the inner layer pipe (20121) is provided with a vent hole (201212) respectively communicated with the air inlet channel (201211) and the buffer chamber (23), and the pipe wall of the outer layer pipe (20122) opposite to the gap (203) is provided with a plurality of air outlets (201221) communicated with the buffer chamber (20123).

7. The plasma cleaning module according to claim 1, wherein two of the gas line assemblies (201) are each connected to a regulating valve for regulating the flow rate of the gas to be ionized injected by the gas line assembly (201).

8. The plasma cleaning module according to claim 1, wherein the electrode plate (202) is internally provided with a bidirectional waterway (2023), the bidirectional waterway (2023) comprises a water inlet channel (20233) and a water outlet channel (20234), a liquid inlet (20231) for allowing cooling liquid to enter is arranged on the water inlet channel (20233), a liquid outlet (20232) for allowing cooling liquid to be discharged outwards is arranged on the water outlet channel (20234), the liquid inlet (20231) and the liquid outlet (20232) are adjacently arranged, one end of the water inlet channel (20233) away from the liquid inlet (20231) and one end of the water outlet channel (20234) away from the liquid outlet (20232) are mutually communicated, and the water outlet channel (20234) is folded back to the liquid outlet (20232) along an extension path of the water inlet channel (20233).

9. The plasma cleaning module of claim 8, wherein the extended path of the water inlet channel (20233) includes a plurality of first peaks (202331) and a plurality of first valleys (202332), the water inlet channel (20233) alternately meandering between the first peaks (202331) and the first valleys (202332);

the extending path of the water outlet channel (20234) comprises a plurality of second wave crests (202341) and a plurality of second wave troughs (202342), the water outlet channel (20234) alternately extends in a zigzag manner between the second wave crests (202341) and the second wave troughs (202342), each of the second wave crests (202341) and a corresponding one of the first wave crests (202331) are adjacently arranged, and each of the second wave troughs (202342) and a corresponding one of the first wave troughs (202332) are adjacently arranged.

10. A plasma cleaning method characterized in that the plasma cleaning module according to any one of claims 1 to 9 is used, the plasma cleaning method comprising the steps of:

placing a circuit board to be cleaned in a gap (203) between two adjacent electrode plates (202);

bringing the pressure in the gap (203) to a preset vacuum pressure value;

the air exhaust assembly (201) is used for introducing quantitative first air into the gap (203), alternating current is introduced into each electrode plate (202), an alternating electric field perpendicular to the magnetic field is generated at the gap (203) between two adjacent electrode plates (202), and the first air is ionized under the combined action of the alternating electric field and the magnetic field to form first plasma and bombard the circuit board to be cleaned, so that the temperature of the circuit board to be cleaned reaches a preset temperature value;

and the air exhaust assembly (201) is used for introducing quantitative second air into the gap (203), molecules of the second air are ionized under the combined action of an alternating electric field and a magnetic field to form second plasmas, and the surfaces and the holes of the circuit board to be cleaned are etched by the second plasmas so as to remove impurities on the surfaces and in the holes of the circuit board to be cleaned.