System for inspecting and correcting a protective layer deposited on an electronic board, and corresponding method

Abstract

The present invention relates to a system for inspecting and correcting a protective layer deposited on an electronic board, this protective layer being a layer of a tropicalizing varnish comprising an irradiation-curable resin, defined by a real state corresponding to a real geometry and / or a real thickness, this system comprising: - an inspection module, configured to inspect the real state of the protective layer; - a computer unit, comprising recording means configured to store data representative of at least two predetermined states relating to the surface state of the protective layer (a compliant state and a state with excess tropicalizing varnish), and also comprising means for comparing the real geometry and / or the real thickness of the protective layer with the data of the compliant and excess tropicalizing varnish states;- an ablation module, configured to remove at least one area of ​​the protective layer and communicating with the computer unit; and - an irradiation polymerization module for the tropicalization varnish, comprising a device emitting energetic radiation and communicating with the computer unit. The present invention also relates to a method for inspecting and correcting a protective layer deposited on an electronic board and implemented by the above system. Figure for the abstract: 1;

Description

Title of the invention: System for inspecting and correcting a protective layer deposited on an electronic board, and corresponding method Technical field of the invention

[0001] The present invention relates to the general field of electronic circuit board manufacturing.

[0002] The invention relates more particularly to a system for inspecting and correcting a protective layer based on a polymerizable tropicalizing varnish deposited on an electronic board. The invention also relates to a method for inspecting and correcting such a system. Technical background

[0003] Electronic boards are now widely used in modern electronics. For example, they are currently used in motor control systems, such as those for car or aircraft engines. They are also used, for example, in the field of semiconductor packaging, commonly referred to as "semiconductor packaging".

[0004] In particular, such electronic boards are very often embedded in electronic systems. These electronic boards are particularly likely to be placed in harsh environments and thus subjected to difficult external conditions. For example, depending on the electronic systems, these electronic boards may be subjected to significant variations in physicochemical parameters, such as temperature, humidity, or salinity. These variations in physicochemical parameters within electronic systems result in significant thermomechanical stresses, stresses which are primarily due to the differential expansion of the various materials composing these systems.

[0005] Such electronic boards may also be subjected to acid splashes, or to contact with abrasive elements or liquids.

[0006] To remedy these problems, it is generally proposed to tropicalize electronic boards, that is, to coat them with layers of at least one protective material, called tropicalization layers, helping them to withstand the external conditions to which they are subjected. Furthermore, electronic boards, particularly in the field of electronic assembly, generally contain SMD (Surface Mount Device) and THT (Through-Hole Technology) components. through holes"), with a solution for protection against environmental aggressions.

[0007] In particular, this tropicalization process makes it possible to make the electronic functions of the system in which an electronic card thus protected is located more robust.

[0008] Protective materials are generally polymers, with or without the addition of particles, such as metallic particles. In particular, one of the protective layers, for example the last one deposited, is a layer of a tropicalizing varnish, which comprises an irradiation-curable resin. This varnish layer includes an outer surface exposed to air.

[0009] Conventionally, the surface condition of the outer surface of the varnish layer is measured in order, among other things, to check its flatness and / or determine its roughness. This makes it possible, in particular, to identify areas with an excess of varnish, as well as areas with a lack of varnish. Based on the measured surface condition, it is possible to deduce whether the varnish layer conforms or not, in particular, to predetermined values ​​defining areas of conforming varnish.

[0010] Currently, the deposition of the varnish layer and the measurement of its surface condition are carried out either manually or automatically using an automated system employing, for example, one or more robots.

[0011] Furthermore, when an area with an excess of varnish has been identified, this area is rectified, for example, by removing the excess material if necessary during an ablation operation, until this area can be considered compliant.

[0012] It is known to carry out this ablation manually, by operators, for example using one or more chemical solvents, such as methyl ethyl ketone.

[0013] However, manually performing such an ablation in the field of electronic circuit board manufacturing presents several disadvantages.

[0014] Indeed, having to perform this ablation manually necessarily entails significant operational costs, while knowing that the reliability of such a manipulation is then not optimal.

[0015] Furthermore, due to the proven toxicity and flammability of chemical solvents, their use is harmful and dangerous to the health of the operators handling them. The use of chemical solvents is also not optimal from an environmental point of view, given their considerably high carbon footprint.

[0016] Currently, in some cases, it is therefore decided not to proceed with this manual removal, and it is preferable to remove the electronic board during production for destruction. This destruction has a negative environmental impact. due to the need to recycle the materials constituting the electronic board to be destroyed, and also presents a negative economic impact, due to having to restart the production of the electronic board that is ultimately destroyed.

[0017] Thus, there is a need for a system which allows the surface condition of this varnish layer to be inspected and corrected reliably, while eliminating the need for human manipulation.

[0018] There is also a need for such a system which makes it possible to reduce the health risks to users resulting from the electronic card manufacturing systems currently implemented.

[0019] There is still a need for such a system that reduces the costs and environmental impact resulting from prior art systems currently in use. Summary of the invention

[0020] Thus, the present invention relates to a system for inspecting and correcting a protective layer deposited on an electronic board, this protective layer being a layer of a tropicalizing varnish comprising an irradiation-curable resin, defined by an actual state corresponding to an actual geometry and / or an actual thickness, this system comprising: - an inspection module comprising a fixed camera or a camera mounted on an axis, this inspection module being configured to inspect the actual condition of the protective layer; - a computer unit comprising: — recording means configured to store data representative of at least two predetermined states relating to the surface state of the protective layer: — a conforming state (El), corresponding to a geometry and / or thickness of a predetermined value, — a state with an excess of tropicalization varnish, corresponding to a geometry and / or thickness respectively greater than the geometry and / or thickness of a predetermined value, — means of comparing the actual geometry and / or thickness of the protective layer with the geometries and / or thicknesses of the conformal and excess tropicalization varnish states; - an ablation module comprising a laser and an optical galvanometer, this ablation module being configured to remove at least one area of ​​the protective layer, this ablation module communicating with the computer unit; and - a module for irradiation polymerization of the tropicalization varnish comprising a device emitting energetic radiation, this polymerization module communicating with the computer unit.

[0021] The system according to the invention thus makes it possible to inspect and correct, by removing varnish, in a fully automated manner, the geometry of a tropicalization varnish layer deposited on an electronic board, using a single piece of equipment. In other words, the system according to the invention eliminates the need for any human intervention in the process of applying a tropicalization varnish layer to an electronic board.

[0022] For the purposes of the present invention, the geometry of a tropicalizing varnish layer means the shape of that layer. Preferably, this shape is defined in two or three dimensions in a coordinate system to which the computer unit is connected.

[0023] An electronic card implemented in the system of the invention integrates components, such as electronic or mechanical components: for example, these components may be, among many other components, resistors or transistors.

[0024] The system according to the invention is thus able to:

[0025] - to visually inspect the surface condition, and in particular the geometry, of the layer of tropicalization varnish that has just been applied to an electronic circuit board,

[0026] - to determine if this varnish layer needs to be corrected, so that it fills properly fulfilling its protective function,

[0027] - to perform this correction automatically, if necessary, particularly by material removal, and

[0028] - to solidify this varnish layer by irradiation polymerization.

[0029] Whereas prior art systems are only inspection systems, the system of the invention is both an inspection and correction system.

[0030] In the prior art, once the inspection system has automatically determined that the protective layer needs to be corrected, in particular to remove excess varnish that prevents the protective layer from optimally fulfilling its protective role, the next step of correction by varnish removal is carried out by a human operator. This operator removes the excess varnish manually, most often using a chemical solvent which is, unfortunately, hazardous to their health and to the environment.

[0031] Furthermore, in certain cases, when prior art inspection systems detect a defect in the varnish layer, particularly an excess of material, it is decided not to perform this manual correction operation and to discard the electronic board under manufacture: indeed, depending on the geometry of the area Due to the defective varnish layer, the operational cost of correction may be too high compared to the cost of manufacturing and protecting the circuit board in question. In such a case, the defective circuit board is considered non-compliant and uncorrectable.

[0032] On the contrary, in the system of the invention, once the inspection module has identified the presence of a defect in the geometry of the deposited varnish layer, in particular an excess of material, it is able to operate the removal of this quantity of excess varnish itself, thanks to a material removal module present in the automated system, communicating with a computer unit, which controls the whole system.

[0033] The operational cost of such automated correction is significantly lower than the cost of manual correction. Correction operations are therefore advantageously systematized by the system of the invention, and the implementation costs of manufacturing and protecting electronic boards are also reduced.

[0034] Furthermore, eliminating the need for manual and chemical correction of protective layers on electronic boards reduces risks to the health of human operators and to the environment. Laser material ablation is a green alternative to chemical solvent ablation.

[0035] Thus, according to the invention, a single piece of equipment makes it possible to implement a final protection method for electronic cards.

[0036] The deposition of a layer of tropicalizing varnish as a protective element on an electronic board is also known under the formulation "conformal coating" in English (for "conformal coating" in French).

[0037] Advantageously, the system according to the invention further comprises a tropicalization varnish application module comprising a system consisting of at least one shaft associated with a micro-dosing head, the recording means presented above being further configured to memorize data representative of an additional predetermined state for the protective layer, this state being a state with a lack of tropicalization varnish, corresponding to a geometry and / or a thickness respectively less than the geometry and / or thickness of a predetermined value.

[0038] The system according to the invention therefore also makes it possible to automatically correct geometric defects in the protective layers that correspond to a lack of varnish. This system thus advantageously allows for the complete and optimal correction of the protective layers of electronic boards, and in particular for the correction of several types of geometric defects in these protective layers.

[0039] According to the invention, the micro-dosing head of the application module can be chosen from a valve, a needle, a spray or a jet.

[0040] Advantageously, the energetic radiations emitted by the energetic radiation emitting device are chosen from visible light, infrared, gamma, ultraviolet, laser, microwave, X-ray, and convective or conductive thermal deployment radiations.

[0041] The polymerization module of the system of the invention may advantageously include any type of energetic radiation emitting device capable of operating the polymerization of a layer of polymerizable material.

[0042] According to a particular embodiment, these energetic radiations are chosen from infrared and ultraviolet radiations.

[0043] Infrared and ultraviolet radiation are very effective for polymerizing a layer of tropicalizing varnish based on a polymerizable resin.

[0044] Advantageously, the system according to the invention further comprises a module for depositing the protective layer on the electronic board, this depositing module being a system consisting of at least one axis associated with a micro-dosing head.

[0045] The system according to the invention is therefore suitable for intervening upstream of a varnish layer deposition line, in particular on electronic boards (otherwise called a "varnishing line"): it can in fact carry out the deposition of a varnish layer on an electronic board itself.

[0046] The system according to the invention can thus be at once a depositing, inspection and correction system.

[0047] According to the invention, the micro-dosing head of the deposition module can be selected from a valve, a needle, a spray or a jet.

[0048] The invention also relates to a method for inspecting and correcting a protective layer deposited on an electronic board, this protective layer being a layer of a tropicalization varnish comprising an irradiation-curable resin, defined by an actual state corresponding to an actual geometry and / or an actual thickness, this method comprising the following steps: A1) inspection of the actual state of the protective layer; B1) Comparison of the actual geometry and / or actual thickness with representative data for at least two predetermined states for the protective layer, these states being: - a conforming state, corresponding to a geometry and / or thickness of a predetermined value, - a state with an excess of tropicalization varnish, corresponding to a geometry and / or thickness respectively greater than the geometry and / or thickness of a predetermined value, Cl) determination to which predetermined state corresponds the actual state of the protective layer; Dl) when the actual state of the protective layer corresponds to the state with excess tropicalization varnish, removal of the excess tropicalization varnish at the level of the protective layer by laser beam, to obtain an actual geometry and / or an actual thickness corresponding respectively to the geometry and / or thickness of a predetermined value; El) Irradiation polymerization of the tropicalization varnish of the protective layer.

[0049] The method according to the invention offers at least the same advantages as those associated with the system implementing it and detailed above. This method is implemented by a single inspection and correction system: it is therefore simpler to implement than prior art methods, and this implementation is less costly, reducing the negative impact on humans and the environment.

[0050] According to an advantageous embodiment, the process according to the invention further comprises the following step: Fl) application of tropicalization varnish at the level of the protective layer when the determination of step Cl determines that the actual geometry and / or actual thickness of the protective layer corresponds to an additional predetermined state corresponding to a state with lack of tropicalization varnish, associated with a geometry and / or a thickness respectively less than the geometry and / or thickness of a predetermined value, to obtain an actual geometry and / or an actual thickness corresponding respectively to the geometry and / or thickness of a predetermined value.

[0051] Similar to the system of the invention presented above, the method which implements the system of the invention is able to correct a defect in the varnish layer deposited on the inspected electronic board which corresponds to a lack of material.

[0052] Advantageously, the process according to the invention further comprises the following steps: B2) after the removal of step Dl and / or the application of step Fl, repeat the comparison of step B1 and the determination of step Cl; then D2a) when the actual geometry and / or thickness of the protective layer again corresponds to the state with excess tropicalization varnish, repeat the removal step D1 to obtain an actual geometry and / or thickness corresponding respectively to the geometry and / or thickness of a predetermined value, then implement the polymerization step El, and / or D2b) when the actual geometry and / or thickness of the protective layer again corresponds to the state with insufficient tropicalization varnish, repeat the application of step Fl to obtain an actual geometry and / or thickness actual corresponding respectively to the geometry and / or thickness of a predetermined value, then implementation of the polymerization of step El, or D2c) when the actual geometry and / or actual thickness of the protective layer corresponds respectively to the geometry and / or thickness of a predetermined value, implementation of the polymerization of step El.

[0053] The method according to the invention can thus be implemented iteratively, circulating the inspected electronic board through the system of the invention in a loop. The electronic board first passes through the system's inspection module. If this module, which is coupled to the system's computer unit, determines that the varnish layer covering the electronic board has one or more defects characteristic of a lack of varnish, an excess of varnish, or a combination of these two defects, the electronic board passes through the system's modules that correct this or these defects. The computer unit then returns the corrected electronic board to the inspection module to analyze the geometry of the corrected varnish layer and determine whether the correction(s) made have brought the actual state of this varnish layer into a compliant state.If this state is indeed compliant, the computer unit sends the electronic board to the system's polymerization module to finalize the protection of the electronic board. Conversely, if this state is still non-compliant, due to a lack and / or excess of varnish, the electronic board continues its loop through the system of the invention and is sent by the computer unit to the system module(s) that allow for the appropriate correction of the varnish layer's geometry until the actual state of this varnish layer is considered compliant.

[0054] According to an advantageous embodiment, the removal and application steps are carried out on separate areas of the protective layer.

[0055] Thus, the inspection module of the system implemented in the method of the invention makes it possible to determine that a single layer of tropicalizing varnish on an electronic board exhibits both areas with insufficient varnish and areas with excess varnish. In this case, the method of the invention allows the electronic board coated with this varnish layer to be passed through the two modules of the system, which respectively allow for the application of additional varnish to the affected area(s) of the electronic board and the removal of varnish from the affected area(s) of the electronic board. The method according to the invention therefore makes it possible to correct several types of defects present on the same electronic board.

[0056] Advantageously, the process according to the invention further comprises a step A0 of depositing the protective layer on the electronic board. Brief description of the figures

[0057] Other objects, features and advantages of the invention will become more apparent from the following description, given by way of simple illustrative, and not limiting, example, in relation to the figures, among which:

[0058] [Fig-1]: [Fig.1] schematically illustrates the inspection and correction of a protective layer according to the invention;

[0059] [Fig.2]: [Fig.2] schematically illustrates the operation of inspecting the protective layer of an electronic board in manufacture, which is implemented by the system of [Fig.1], at the level of a first position of the system;

[0060] [Fig.3] : The [Fig.3] schematically illustrates the tropicalization varnish removal operation which is implemented by the system of the [Fig.1], at the level of a second position of the system;

[0061] [Fig.4] : The [Fig.4] schematically illustrates the tropicalization varnish application operation which is implemented by the system of the [Fig.1], at the level of a third position of the system;

[0062] [Fig.5] : The [Fig.5] schematically illustrates the polymerization operation of the protective layer which is implemented by the system of the [Fig.1], at the level of a fourth position of the system. Detailed description of the invention

[0063] The system 1 for inspecting and correcting a protective layer of an electronic board according to the invention is illustrated schematically and generally in [Fig.1].

[0064] The system of the invention is configured to analyze and process electronic boards that do not have a radius of curvature. That is to say, the surface of the electronic boards that is in contact with the various modules of the system of the invention on which these boards are placed is essentially flat. As for the surface of the electronic boards on which the tropicalization varnish is deposited, this may be non-flat and may, for example, have projections and protrusions corresponding to the geometry of the components integrated on these electronic boards.

[0065] This system 1 includes, at a first position, an inspection module 11, which is a vision system, configured to analyze the actual state of the protective layer deposited on an electronic board.

[0066] It also includes a computer unit 12, configured to receive analysis data from the inspection module 11 and compare it with predetermined data, previously entered into this computer unit 12, relating to predetermined states for the protection layer. This computer unit 12 makes it possible to classify the state of the inspected protection layer into one of these predetermined states, and to send the electronic board accordingly to a module of the The system is adapted for the continuation of the inspection and finalization process of the electronic board protection. Computer unit 12 communicates with all the modules of system 1.

[0067] In a second position, the system 1 according to the invention comprises a tropicalization varnish ablation module 13, configured to remove excess varnish from the protective layer when the computer unit 12 has classified the state of the protective layer as having an excess of tropicalization varnish. This ablation module 13 communicates with the computer unit 12, which is configured, among other things, to send the electronic board of the inspection module 11 to the ablation module 13. This ablation module 13 is, for example, a digital ablation system: when activated, it removes excess varnish by applying repeated energy pulses to the varnish area to be removed.This digital implementation of the ablation operation allows for the gradual and repetitive removal of excess varnish from the circuit board, as opposed to a continuous process where the excess varnish is removed all at once through continuous energy irradiation of the area to be treated. This digital ablation step is therefore broken down into numerous sub-ablation operations, each of which delivers an energy pulse to the varnish area to be removed. Each energy pulse is thus easily controlled and monitored, and the condition of the treated varnish surface after each energy pulse is verified by the inspection module.Through successive iterative loops between digital energy pulses and control imaging, the system according to the invention makes it possible to ensure that the excess varnish has been removed without damaging the surface of the electronic board.

[0068] At a third position, the system 1 includes a tropicalizing varnish application module 14, configured to deposit an additional quantity of varnish in at least one area of ​​the protective layer when the computer unit 12 has classified the protective layer as having a predetermined varnish deficiency. This application module 14 also communicates with the computer unit 12, which is configured, among other things, to send the electronic card of the inspection module 11 to the application module 14. This application module 14 is, for example, a digital application system. Similar to the digital ablation system described above, this digital deposition system, when implemented, applies an additional quantity of varnish through multiple and repeated sub-operations of varnish droplet deposition: the additional material is deposited point by point.Conversely, a continuous implementation of a material application operation only allows additional material to be applied continuously: during such a continuous operation, the missing quantity. The material is applied in a single step. Thus, mirroring the digital implementation of the ablation operation, each droplet of varnish deposited is easily controlled and monitored, and the condition of the treated varnish surface after each droplet application is verified by the inspection module. Through successive iterative loops between digital varnish application and control imaging, the system according to the invention ensures that the exact amount of varnish needed has been deposited, without excess.

[0069] Also, at a fourth position, the system 1 according to the invention includes a polymerization module 15 for the protective layer, configured to polymerize the tropicalization varnish that constitutes this layer and which comprises a polymerizable resin, after this layer has been optionally corrected by the ablation module 13 and / or the application module 14. Following the passage of the electronic board through this polymerization module 15, the protective layer covering it is solidified, and the manufacturing and protection of the electronic board is thus completed. This polymerization module 15 also communicates with the computer unit 12, which is configured, among other things, to send the electronic board from the inspection module 11, the ablation module 13, or the application module 14 to the polymerization module 15. This polymerization module 15 is, for example, a digital polymerization module.It will be readily understood that, like the digital ablation module and the digital application module, this digital polymerization module allows for the gradual and repetitive irradiation of the area of ​​the varnish surface to be polymerized with energetic radiation. The area to be irradiated is artificially segmented into several portions, and the digital polymerization module irradiates each portion one after the other until the entire area is irradiated. This digital implementation of the polymerization operation offers the same advantages as those associated with the digital implementation of ablation and application operations, resulting in more precise and efficient polymerization than that obtained through a continuous polymerization process. In particular, it avoids impacting areas that do not require energy input.

[0070] As illustrated in this [Fig.1], the system 1 of the invention is also able to return the electronic board located at the level of the ablation module 13 or the application module 14 to the inspection module 11, before passing through the polymerization module 15, in order to analyze the geometry of the varnish layer which has been corrected by one or both of these modules.

[0071] The embodiment of system 1 of the invention illustrated in [Fig.1] also includes a deposition module 16 for the tropicalization varnish layer, located upstream of the inspection module 11.

[0072] The protective layer P can be applied, inspected and corrected on both sides of the electronic board C.

[0073] Figures 2 to 5 schematically illustrate the operations which are implemented at the level of the different modules and positions of system 1 of the invention.

[0074] Fig. 2 illustrates the inspection operation of the protective layer P of the electronic board C in manufacture, which is implemented at a first position in system 1.

[0075] During this inspection operation, the electronic card C, which is introduced into the system 1 and on which a protective layer P consisting of a tropicalization varnish has just been deposited, is guided to the inspection module 11.

[0076] The composition of the tropicalization varnish comprises one or more acrylates, and / or one or more polyurethanes, and / or one or more polysiloxanes, and / or one or more polyepoxides.

[0077] This inspection module 11 is a vision module, and consists either of one or more fixed cameras, or of one or more cameras mounted on an axis and therefore mobile.

[0078] At this first position of the system 1, the vision module 11 inspects the real state ER of the protective layer P: in this example, this state is characterized by a geometry and / or a thickness.

[0079] In other embodiments of the invention, this state of the protective layer P can be characterized by other parameters, such as physical and / or chemical and / or visual parameters.

[0080] In the case of [Fig.2], the vision module 11 of the system 1 determines the actual geometry GR and / or the actual thickness ER of the protective layer P. According to a specific example, this analysis of the actual geometry GR corresponds to the analysis of the shape of the protective layer P, i.e. to the identification of the areas of the surface of the electronic board C actually covered or not by the varnish of the protective layer P.

[0081] This actual data is then transmitted to the computer unit 12, which is automated inspection software implemented in a computing medium, such as a computer. This computer unit 12 can also operate using artificial intelligence.

[0082] This unit 12 thus includes the data relating to the actual geometry GR and / or the actual thickness TR of the protective layer P, transmitted by the inspection module 11. This computer unit 12 has also been previously loaded with data relating to several predetermined states for this protective layer P.

[0083] A first predetermined state corresponds to a so-called conforming state El, the associated data of which are predetermined values ​​of geometry G1 and / or thickness Tl of the protective layer P. The predetermined value(s) of the thickness of the tropicalizing varnish layer depend on the varnish deposited, and in particular on the nature of its constituent components. According to one example of the invention, the predetermined thickness of the varnish layer corresponding to the conforming state El is between 50 µm and 200 µm. According to another example, this thickness is between 1 mm and 5 mm.

[0084] A second predetermined state corresponds to a state with excess tropicalization varnish E2, the associated data of which relate to the information according to which all geometry and / or thickness values ​​which are greater than the predetermined values ​​G1 and Tl of the conforming state El fall into the state E2.

[0085] And a third predetermined state corresponds to a state with lack of tropicalization varnish E3, the associated data of which relate to the information according to which all geometry and / or thickness values ​​which are less than the predetermined values ​​G1 and Tl of the conforming state El fall into the state E3.

[0086] In the example where the analysis of the varnish layer geometry corresponds to determining the presence or absence of varnish on the different areas of the electronic board C, the predetermined geometry data G1 entered into the computer unit 12 concern:

[0087] - the location of the areas of the electronic card C for which the presence of the A protective P layer is mandatory.

[0088] - the location of the areas for which the presence of the protective layer P is strictly forbidden, without any possibility of correction.

[0089] - the location of the areas for which the presence of the protective layer P is not mandatory but is permitted, and

[0090] - the location of the areas for which the presence of the protective layer P is forbidden but correctable.

[0091] The computer unit 12 further includes means for comparing the actual geometry GR and / or the actual thickness ER of the protective layer P with data relating to the predetermined states E1, E2, and E3 for this protective layer P. These comparison means enable the computer unit 12 to determine in which predetermined state the inspected protective layer P falls. It therefore allows, through image analysis, validation of the accuracy of the protective layer P's deposition, in terms of geometry and / or thickness.

[0092] According to the particular example cited above, the computer unit 12 is able to determine the absence or presence of varnish at the level of the different areas of the electronic card C.

[0093] Thus, when the electronic card C is positioned at the level of the first position in the system 1, and the result of the comparison carried out by the computer unit 12 is that the actual geometry GR and / or the actual thickness ER of the protective layer P corresponds respectively to the geometry G2 and / or the thickness T2 associated with the state with excess tropicalization varnish E2, the electronic card C is sent to the level of the varnish ablation module 13.

[0094] In particular, if the result of this comparison is that varnish is present in an area of ​​the electronic board C for which the presence of the protective layer P is prohibited but correctable, the computer unit 12 sends the electronic board to the ablation module 13, so that the latter can ablate the excess material.

[0095] Figure 3 illustrates such a varnish removal operation at the level of the layer of protection P, implemented at the level of a second position in system 1 of the invention.

[0096] This ablation module 13 consists of a laser associated with an optical galvanometer.

[0097] According to one embodiment, this ablation operation comprises several steps. Initially, the laser of module 13 is activated and delivers a defined dose of energy, set to a minimum energy threshold, to the area of ​​the protective layer P identified as having an excess of varnish. For example, this defined dose of energy is an electrical power ranging from a few tens of watts (W) to a few tens of kilowatts (kW). This power depends on the type of varnish to be cured and its thickness. The power is adjusted proportionally according to the nature of the ablation step to be performed, that is, according to the amount of material to be removed.For example, when removing tropicalization varnish from a circuit board, the laser in module 13 applies pulses of around ten watts, because the thickness of a tropicalization varnish layer is generally between 20 and 100 micrometers (also known as pm). And when removing a varnish containing one or more polyepoxides, particularly in semiconductor packaging, the laser in module 13 applies pulses of around ten kilowatts, because the thickness of such a polyepoxide-based varnish layer is generally between 10 and 500 pm.

[0098] Then, the electronic card C is returned to the first position of system 1, at the inspection module 11. This module visually analyzes the actual geometry GR and / or the actual thickness ER of the corrected protective layer P, and transmits these information to computer unit 12. The latter compares this new real data with the data relating to the predetermined states El to E3.

[0099] If the computer unit 12 determines that, after correction, the actual state ER of the protective layer P still corresponds to the state with excess varnish E2, it returns the electronic board C to the ablation module 13. The laser of the ablation module 13 delivers a new defined dose of energy, set to the same minimum energy threshold. Then the electronic board C is returned to the inspection module 11 for visual inspection again.

[0100] These varnish removal and visual inspection steps of the corrected protective layer P are repeated until the computer unit 12 determines that the actual state ER of the protective layer P corresponds to the conforming state El.

[0101] An example of an area of ​​the electronic board C where the presence of varnish is prohibited but correctable is the area containing the high-density two-dimensional barcode, commonly called a "Datamatrix" in English (for "matrice de données" in French). This element is generally located near one of the peripheral edges of the electronic board C. Thus, if the system of the invention determines that a projection of the tropicalization varnish is present in this area of ​​the Datamatrix, the ablation module 13 removes this excess material, under certain conditions. Indeed, micro-projections in the Datamatrix area are acceptable and do not need to be removed. On the other hand, projections larger than micro-projections are considered non-compliant and must be removed by the ablation module.As an example, the size of an acceptable micro-projection is defined as being at least five times smaller than the size of a dot (for "point" in French) that is part of a Datamatrix.

[0102] Another example of correctable varnish excess corresponds to the identification of varnish bubbles at the level of the protective layer, which can be removed by the ablation module 13.

[0103] It is also possible that, following the varnish removal operation and the check of the thus corrected protective layer P, the computer unit 12 determines that the actual state ER of the protective layer P corresponds directly to the conforming state El. In this case, the electronic board C is not returned to the removal module 13, but goes to the polymerization module 15: this step will be described in detail later.

[0104] According to one embodiment of the invention, the laser of the ablation module 13 is also used upstream of the application of the tropicalization varnish to the electronic board, in order to prepare the surface of the electronic board in question. before applying this varnish. This allows the surface of the electronic board to be textured before the varnish is applied, to improve the adhesion of the varnish to this surface.

[0105] Furthermore, when the electronic board C is positioned at the first position in the system 1, either for the very first time or following one or more ablation operations, the result of the comparison performed by the computer unit 12 may also be that the actual geometry GR and / or the actual thickness ER of the protective layer P corresponds respectively to the geometry G3 and / or the thickness T3 associated with the state lacking tropicalization varnish E3. In this case, the electronic board C is sent to the varnish application module 14, in a third position of the system.

[0106] Fig. 4 illustrates such an operation of applying varnish to the level of the protective layer P.

[0107] The application module 14 is a system consisting of one or more micro-dosing heads, each of these heads being associated with one or more axes. The micro-dosing head is selected, in particular, from a valve, a needle, a spray, or a jet.

[0108] Similar to the ablation operation which is implemented at the level of the second position of system 1, according to one embodiment, this material application operation comprises several steps.

[0109] Initially, the micro-dispensing head applies a defined quantity of polymerizable material to the area of ​​the protective layer P that has been identified as lacking varnish. For example, this micro-dispensing head deposits a series of droplets with diameters ranging from 50 µm to 500 µm. The size of the deposited droplets is parameterized according to the resolution and nature of the correction sought. For instance, for the application of a weathering varnish to a circuit board, the micro-dispensing head deposits droplets with diameters between 250 µm and 500 µm. And for the application of varnishes comprising one or more polyepoxides, particularly in semiconductor packaging, the micro-dispensing head deposits droplets with diameters between 50 µm and 100 µm.

[0110] Following this initial varnish application step, the electronic board C is returned to the inspection module 11. This module visually analyzes the actual geometry GR and / or the actual thickness ER of the protective layer P and transmits this information to the computer unit 12. The latter compares this actual data with the data relating to the predetermined states El to E3. If the computer unit 12 determines that the actual state ER of the protective layer P corresponds to the conforming state El, it sends the electronic board C to the polymerization module 15, so that the protective layer P can be solidified, and thus the electronic board C can be finalized.

[0111] Conversely, if the computer unit 12 determines that the actual state ER of the protective layer P still corresponds to the state with a lack of varnish E3, it returns the electronic board C to the application module 14, so that the latter can re-deposit a defined quantity of varnish in the area of ​​the protective layer P to be treated. Then, the electronic board C is returned to the inspection module 11, to the first position of the system, to be visually inspected again.

[0112] Furthermore, if, following the first post-varnish application check at the third position of system 1, the computer unit 12 determines that the actual state ER of the protective layer P now corresponds to the state with excess varnish E2, it sends the electronic board C to the ablation module 13 at the second position of the system, so that the laser of this module removes an excess amount of varnish from the area of ​​the protective layer P to be treated. Then, in the same manner, the electronic board C is returned to the inspection module 11 for another visual inspection.

[0113] These steps of applying or removing tropicalizing varnish and visually checking the protective layer P are repeated, in one direction or the other, until the computer unit 12 determines that the actual state ER of the protective layer P corresponds to the conforming state El.

[0114] The varnish application step is particularly effective, since the system 1 of the invention makes it possible, during the process of correcting the protective layer P, to determine precisely the quantity of additional material that is applied, and therefore to optimally follow the evolution of the correction of the geometry and / or the thickness of the protective layer P, in order to obtain a conforming protective layer as simply and efficiently as possible.

[0115] These varnish removal and application steps can also be implemented on the same electronic board C. In such a case, the inspection module 11 and the computer unit determine that the inspected electronic board includes one or more areas with a lack of varnish and one or more areas with an excess of varnish, and clearly identify these different geographical areas. The computer unit 12 then sends the electronic board C, which is positioned at the inspection module 11, to the varnish removal module 13 and controls the latter to perform material removal on the area(s) identified as having an excess of varnish.Then it sends the electronic board C back to the inspection module 11, to analyze whether the corrected areas of the electronic board C correspond to the compliant state EL. Next, the computer unit 12 sends the electronic board C to the varnish application module 14 and controls the latter to deposit material on the area(s) identified as lacking varnish. Then it sends the electronic board C back to the inspection module 11. to analyze whether the corrected areas of the electronic board C correspond to the compliant state El. Note that the method according to the invention can implement the ablation operation(s) before or after the application operation(s).

[0116] According to a variant of the invention, when the inspection module 11 and the computer unit determine that the inspected electronic board C includes one or more areas with a lack of varnish, and one or more areas with an excess of varnish, the computer unit 12 sends the electronic board C to the varnish removal module 13, then directly to the varnish application module 14 (or vice versa), and only then sends the fully corrected electronic board C back to the inspection module 11, to analyze whether the entire corrected electronic board C corresponds to the compliant state El.

[0117] In all cases, these varnish removal and application steps are repeated, in one direction or the other, until the computer unit 12 determines that the actual state ER of the electronic board C corresponds to the conforming state El.

[0118] Following the varnish removal and / or application steps, at the second and third positions respectively in system 1, as soon as the computer unit 12 determines that the actual state ER of the varnish layer corresponds to the conforming state El, it sends the electronic board C to a fourth position in system 1, which includes a polymerization module 15.

[0119] Fig. 5 illustrates this polymerization operation of the tropicalization varnish of the protective layer P.

[0120] This polymerization module 15 is an irradiation polymerization module and includes an emitting device configured to emit energetic radiation selected from visible light, infrared, gamma rays, ultraviolet, lasers, microwaves, X-rays, and convective or conductive thermal radiation. According to a preferred embodiment of the invention, this device is an emitting source of infrared or ultraviolet radiation.

[0121] This emitting device can be fixed and chosen from a matrix comprising one or more independent emitting sources, such as LEDs, and an emitting source associated with an optical galvanometer.

[0122] This transmitting device can also be mobile, and be for example a mobile transmitting source mounted on an axis.

[0123] When the polymerization module 15 irradiates the protective layer P, the polymerizable resin-based varnish constituting this layer solidifies, which allows the fabrication of the electronic board C to be finalized, and its integrated components to be fully protected.

[0124] Furthermore, according to an example of the invention, at the end of the very first inspection step of the electronic card C which has just entered the system 1 of In the invention, the computer unit 12 determines that the actual state ER of the protective layer P corresponds directly to the conformal state El. In this case, it sends the electronic board C directly to the polymerization module 15, without going through the ablation module 13, or the application module 14.

[0125] Optionally, the system 1 according to the invention further includes a deposition module 16 of the protective layer P. In this case, the system 1 itself deposits the protective layer P which it will inspect, possibly then correct it, and then polymerize it.

[0126] Such a deposition module 16 is a system equivalent to the varnish application module 15 used to correct the protective layer P when it corresponds to a state with a lack of varnish E3.

[0127] According to one embodiment of the invention, the inspection and correction system 1 is arranged such that the electronic board C is fixed within the system 1. In this case, the inspection module 11, the ablation module 13, the application module 14, and the polymerization module 15, or even the deposition module 16, are grouped together in a single system structure located above the electronic board C. Thus, according to this example, the system of the invention is single-position (the position that receives the electronic board C) and comprises a vision module 11 placed above this single position, as well as a single laser head configured to perform the varnish ablation operation, the varnish deposition operation, and the polymerization operation of this varnish layer. This polymerization can be by thermal or ultraviolet irradiation.

Claims

Demands

1. System (1) for inspecting and correcting a protective layer (P) deposited on an electronic board (C), said protective layer (P) being a layer of a tropicalizing varnish comprising an irradiation-curable resin, defined by an actual state (ER) corresponding to an actual geometry (GR) and / or an actual thickness (TR), said system (1) comprising: - an inspection module (11) comprising a fixed camera or a camera mounted on an axis, said inspection module (1) being configured to inspect the actual state (ER) of said protective layer (P);- a computer unit (12) comprising: — recording means configured to store data representative of at least two predetermined states relating to the surface state of said protective layer (P): — a conforming state (El), corresponding to a geometry (Gl) and / or a thickness (Tl) of a predetermined value, — a state with excess tropicalizing varnish (E2), corresponding to a geometry (G2) and / or a thickness (T2) respectively greater than said geometry (Gl) and / or said thickness (Tl) of a predetermined value; — means for comparing said actual geometry (GR) and / or said actual thickness (TR) of said protective layer (P) with said geometries and / or said thicknesses (Gl, G2, El, E2) of said conforming state (El) and with excess tropicalizing varnish (E2);- an ablation module (13) comprising a laser and an optical galvanometer, said ablation module (13) being configured to remove at least one area of ​​said protective layer (P), said ablation module (13) communicating with said computer unit (12); and - a polymerization module (15) by irradiation of said tropicalization varnish comprising a device emitting energetic radiation, said polymerization module (15) communicating with said computer unit (12).

2. System (1) according to claim 1, further comprising a tropicalizing varnish application module (14) comprising a system consisting of at least one shaft associated with a micro- dosage, said recording means being further configured to memorize data representative of an additional predetermined state for said protective layer (P), this state being a state with lack of tropicalization varnish (E3), corresponding to a geometry (G3) and / or a thickness (T3) respectively less than said geometry (Gl) and / or thickness (Tl) of a predetermined value.

3. System according to claim 1 or 2, wherein said energetic radiations emitted by said energetic radiation emitting device are selected from visible light, infrared, gamma, ultraviolet, laser, microwave, X-ray, and convective or conductive thermal deployment radiations.

4. System according to claim 3, wherein said energetic radiations are selected from infrared and ultraviolet radiations.

5. Method for inspecting and correcting a protective layer (P) deposited on an electronic board (C), said method being implemented by a system according to any one of claims 1 to 4, said protective layer (P) being a layer of a tropicalization varnish comprising an irradiation-curable resin, defined by an actual state (ER) corresponding to an actual geometry (GR) and / or an actual thickness (TR), said method comprising the following steps: A1) inspection of said actual state (ER) of said protective layer (P);(11) comparison of said actual geometry (GR) and / or said actual thickness (TR) with representative data of at least two predetermined states for said protective layer (P), these states being: - a compliant state (El), corresponding to a geometry (Gl) and / or a thickness (El) of a predetermined value, - a state with excess tropicalization varnish (E2), corresponding to a geometry (G2) and / or a thickness (T2) respectively greater than said geometry (Gl) and / or thickness (Tl) of a predetermined value; (12) determination to which predetermined state (El, E2) corresponds said actual state (ER) of said protective layer (P); Dl) when said actual state (ER) of said protective layer (P) corresponds to said state with excess tropicalization varnish (E2), ablation of the excess tropicalization varnish at the level of said protective layer (P) by laser beam, to obtain an actual geometry (GR) and / or an actual thickness (TR) corresponding respectively to said geometry (Gl) and / or said thickness (Tl) of a predetermined value; El) polymerization by irradiation of said tropicalization varnish of said protective layer (P).

6. Method according to claim 5, further comprising the following step: Fl) application of tropicalization varnish to said protective layer (P) when said determination of step Cl determines that said actual geometry (GR) and / or said actual thickness (TR) of said protective layer (P) corresponds to an additional predetermined state corresponding to a state with lack of tropicalization varnish (E3), associated with a geometry (G3) and / or a thickness (T3) respectively less than said geometry (Gl) and / or thickness (Tl) of a predetermined value, to obtain an actual geometry (GR) and / or an actual thickness (TR) corresponding respectively to said geometry (Gl) and / or said thickness (Tl) of a predetermined value.

7. A method according to claim 5 or 6, further comprising the following steps: B2) after said removal of step D1 and / or said application of step Fl, repetition of said comparison of step B1 and of said determination of step Cl; then D2a) when said actual geometry (GR) and / or said actual thickness (TR) of said protective layer (P) again corresponds to said state with excess tropicalization varnish (E2), repetition of said removal of step D1, to obtain an actual geometry (GR) and / or an actual thickness (TR) corresponding respectively to said geometry (G1) and / or said thickness (T1) of a predetermined value, then implementation of said polymerization of step El, and / or D2b) when said actual geometry (GR) and / or said actual thickness (TR) of said protective layer (P) again corresponds to said state with lack of tropicalization varnish (E3), repetition of

8. said application of step Fl, to obtain an actual geometry (GR) and / or an actual thickness (TR) corresponding respectively to said geometry (Gl) and / or said thickness (Tl) of a predetermined value, then implementation of said polymerization of step El, or D2c) where said actual geometry (GR) and / or said actual thickness (TR) of said protective layer (P) corresponds respectively to said geometry (Gl) and / or said thickness (Tl) of a predetermined value, implementation of said polymerization of step El. Process according to claim 7, wherein said ablation and application steps are implemented on separate areas of said protective layer (P).

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