Cleaning jig for substrates with electronic components mounted thereon and substrate cleaning method using the same

Abstract

To provide a cleaning jig capable of efficiently removing flux adhering to a surface of a printed circuit board regardless of an adhesion state of the flux or a type of electronic components to be mounted.SOLUTION: A jig 40 is a cleaning jig of a printed circuit board 70 where electronic components are mounted. The jig 40 includes a laminate with a first layer 10, a second layer 20, and a third layer 30 laminated in this order. The first layer 10 has a heating wire 11 as a heating element therein. The second layer 20 deforms more than a specified amount when the laminate is pressed in a layer stacking direction with first pressure. The third layer 30 is configured to absorb and retain therein a cleaning solution for cleaning the printed circuit board 70.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cleaning tool for a substrate on which electronic components are mounted, and a substrate cleaning method using the same. [Background technology]

[0002] Conventionally, there are two main known methods for mounting electronic components on printed wiring boards (hereafter referred to as boards or printed circuit boards): the surface mounting method and the lead insertion mounting method. In the surface mounting method, electronic components are connected to lands provided on the surface of the printed circuit board using solder or the like. In the lead insertion mounting method, leads extending from the electronic components are inserted into through holes formed in the printed circuit board, and the inserted parts are fixed with solder or the like.

[0003] In either case, when solder is used, a flux is used to remove the oxide film on the metal surface and to prevent reoxidation, thereby improving the bonding between the solder and the metal. Flux is made by adding an activator, a solvent, etc. to an organic resin as the main component.

[0004] On the other hand, if flux remains as residue on the surface of a printed circuit board after mounting electronic components, the residue may cause a short circuit between the wiring on the printed circuit board. In addition, the ionic components contained in the residue may react with moisture in the air, causing corrosion of the wiring, increasing the electrical resistance of the wiring, and in extreme cases, causing the wiring to break.

[0005] For this reason, the printed circuit board on which the electronic components are mounted is usually cleaned to remove the flux from the surface of the printed circuit board. Furthermore, an ultrasonic cleaner is often used for this cleaning (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-228654 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the amount of flux used and the state of flux adhesion after mounting are different between the two mounting methods described above. Therefore, when using a conventional cleaning machine such as that disclosed in Patent Document 1 to remove flux, the application time and power of ultrasonic waves differ depending on the mounting method. This causes different damage to the mounted electronic components, so in some cases it may be difficult to use an ultrasonic cleaner.

[0008] Furthermore, depending on the type of mounted electronic component, it may not be possible to impregnate the electronic component with the cleaning liquid in the first place.

[0009] The present disclosure has been made in consideration of the above points, and an object of the present disclosure is to provide a cleaning tool for a substrate on which electronic components are mounted, and a substrate cleaning method using the same, which can efficiently remove flux regardless of the state of adhesion of the flux or the type of electronic components mounted thereon. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the cleaning jig disclosed herein is a cleaning jig for a substrate having electronic components mounted thereon, and includes a laminate in which a first layer, a second layer, and a third layer are laminated in this order, the first layer having a heating element therein, the second layer being deformed by a predetermined amount or more when pressed with a first pressure in the stacking direction of the first to third layers, and the third layer being configured to absorb and retain a cleaning liquid for cleaning the substrate.

[0011] The substrate cleaning method according to the present disclosure is a substrate cleaning method using the cleaning jig, and is characterized by comprising at least the following steps: a first step of preparing a substrate having electronic components mounted on its surface; a second step of causing at least the third layer to absorb the cleaning liquid; a third step of pressing the surface with the cleaning jig while the third layer is in contact with the surface after the second step is performed; a fourth step of generating heat from the heating element to a first temperature after the third step is performed; a fifth step of removing foreign matter remaining on the surface after removing the cleaning jig from the surface and further cleaning the surface with the cleaning liquid; and a sixth step of removing the cleaning liquid from the surface after the fifth step is performed. Effect of the Invention

[0012] According to the present disclosure, flux adhering to the surface of a printed circuit board can be efficiently removed regardless of the state of the flux or the type of electronic component mounted. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view of a cleaning jig according to embodiment 1. FIG. [Diagram 2] 1 is a schematic cross-sectional view of a printed circuit board with a cleaning jig in contact therewith; [Diagram 3] FIG. 2 is a plan view of the printed circuit board before cleaning. [Figure 4] FIG. 2 is a plan view of the printed circuit board and the cleaning jig during cleaning. [Diagram 5] 1 is a flowchart showing a method for cleaning a printed circuit board. [Figure 6] 10 is a flowchart showing another method for cleaning a printed circuit board. [Figure 7A] FIG. 11 is a perspective view of a cleaning jig according to a second embodiment with its exterior open. [Figure 7B] FIG. 11 is a perspective view of a cleaning jig according to a second embodiment with its exterior closed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its uses.

[0015] (Embodiment 1) [Cleaning jig configuration] Fig. 1 is a schematic cross-sectional view of a cleaning jig according to embodiment 1. Fig. 2 is a schematic cross-sectional view of a printed circuit board in a state in which the cleaning jig is in contact with the printed circuit board. Fig. 3 is a plan view of the printed circuit board before cleaning. Fig. 4 is a plan view of the printed circuit board and the cleaning jig during cleaning.

[0016] As shown in Fig. 1, cleaning jig 40 (hereinafter simply referred to as jig 40) includes a laminate formed by laminating a first layer 10, a second layer 20, and a third layer 30 in this order. Note that jig 40 has a component (see Figs. 7A and 7B) that holds the laminate and presses it against the surface of a printed circuit board 70, but for ease of explanation, illustration and explanation of the component are omitted in Figs. 1 to 4.

[0017] 1 to 4, the surface of the printed circuit board 70 on which the first electronic component 80 and the second electronic component 81 are mounted is sometimes referred to as the front surface, and the surface opposite the front surface in the thickness direction is sometimes referred to as the back surface. Furthermore, in the first electronic component 80 and the second electronic component 81, the surface opposite the front surface of the printed circuit board 70 and close to the front surface is sometimes referred to as the back surface. The back surfaces of the first electronic component 80 and the second electronic component 81 are also the mounting surfaces on the printed circuit board 70. Furthermore, the surface opposite the back surface in the thickness direction of the printed circuit board 70 is sometimes referred to as the front surface.

[0018] The first layer 10 has a heating wire 11 as a resistor inside. The heating wire 11 is insulated by an insulating resin. When power is applied to the heating wire 11 from the outside through the wiring 41 (see Figs. 7A and 7B) drawn out to the outside of the first layer 10, the heating wire 11 generates heat due to Joule heating. The temperature of the heating wire 11 and the jig 40 can be adjusted to a desired value by adjusting the power applied to the heating wire 11, specifically the amount of current. The thickness T1 of the first layer 10 is set so that the insulating resin can accommodate the heating wire 11 and, when a plurality of heating wires 11 are provided in the thickness direction as shown in Fig. 1, the insulating resin is provided to a thickness that prevents the heating wires 11 from shorting out with each other. The thickness T1 of the first layer 10 is set so that the insulating resin is provided to a thickness that prevents the heating wire 11 from breaking when the first pressure is applied.

[0019] The second layer 20 is made of a material that deforms by a predetermined amount or more when pressed with a predetermined pressure (hereinafter referred to as the first pressure) in the stacking direction of the above-mentioned stack.

[0020] Such materials include, for example, resin sponge, silicone, gelatin, clay, etc., but the material of the second layer 20 is not limited to these exemplified materials. The thickness T2 of the second layer 20 is set to be larger than the unevenness of the surface of the printed circuit board 70, specifically, the height H2 shown in FIG.

[0021] The third layer 30 is configured to absorb and retain inside a cleaning liquid for removing the flux 90 adhering to the surface of the printed circuit board 70. The cleaning liquid in this case is, for example, an organic solvent.

[0022] The third layer 30 is made of, for example, a porous material. Examples of porous materials include fibrous materials such as paper and loofah, and ethoxysilane compounds, but the material of the third layer 30 is not limited to these exemplified materials. The thickness T3 of the third layer 30 is preferably set to a value larger than the unevenness of the surface of the printed circuit board 70, specifically, the height H2 shown in FIG. 2.

[0023] The first to third layers 10, 20, 30 are configured to be detachable from one another. For example, they may be attached to one another with an adhesive or double-sided tape, and separated from one another by immersing them in a predetermined solvent. The first to third layers 10, 20, 30 may be connected with a connecting member such as a hook-and-loop fastener, and each layer may be peeled off as necessary. The method of connecting / separating the first to third layers 10, 20, 30 is not particularly limited to the above.

[0024] The printed circuit board 70 has at least a main substrate 71, wiring 72, and solder resist 73. The printed circuit board 70 is provided with through holes (not shown) that reach from the front surface to the back surface, and a metal layer (not shown) that covers the inner surface of the through hole and is connected to the wiring 72, but for convenience of explanation, these are not shown and will not be described in detail. A ground layer (not shown) may be provided on the back surface of the printed circuit board 70, and internal wiring (not shown) that connects to the wiring 72 or the ground layer via a through hole may be provided inside the main substrate 71.

[0025] Solder resist 73 is provided to cover the wiring 72 except for the connection portions with first electronic component 80 and second electronic component 81, thereby protecting wiring 72. The sum of the thickness of wiring 72 and the thickness of solder resist 73, that is, height H2 shown in Fig. 2, is usually about 10 µm to several tens of µm. Furthermore, first electronic component 80 and second electronic component 81 may be collectively referred to simply as electronic components.

[0026] 1 and 2, the third layer 30 has a notch of width W1 in the center. As shown in Fig. 2, the position and size of the notch are set so that the second electronic component 81 mounted on the surface of the printed circuit board 70 fits into the notch when the jig 40 is brought into contact with the surface of the printed circuit board 70. In other words, the shape of the third layer 30 is set so that the third layer 30 does not come into contact with the surface of the second electronic component 81. This will be described further below.

[0027] Furthermore, the sum of the thicknesses (T1+T2+T3) of the first to third layers 10, 20, 30 is set so that it is not too small relative to the height H1 from the surface of the printed circuit board 70 to the surface of the electronic component. In this way, deformation and breakage of the heating wire 11 can be suppressed, and the third layer 30 can be reliably abutted against the surface of the printed circuit board 70.

[0028] The first electronic component 80 shown in Figures 3 and 4 is, for example, a semiconductor element such as an LSI (Large Scale Integration), or a passive element such as a chip resistor, a chip capacitor, or a chip inductor. On the other hand, the second electronic component 81 is, for example, a temperature and humidity sensor. Therefore, if cleaning liquid adheres to the surface of the temperature and humidity sensor which is the second electronic component 81, the temperature and humidity sensor will not operate normally. In this way, the second electronic component 81 is an element whose normal operation is hindered by at least the cleaning liquid adhering to its surface. Therefore, in addition to the temperature and humidity sensor, the second electronic component 81 also includes a light receiving IC and the like.

[0029] 4, the jig 40 has a cutout shape such that the third layer 30 does not come into contact with the second electronic component 81. In this case, the third layer 30 is shaped so as to be spaced apart from the side surface of the second electronic component 81. In this way, even if the jig 40 is pressed and cleaning liquid splashes out from the third layer 30, the cleaning liquid can be prevented from adhering to the surface of the second electronic component 81.

[0030] In the example shown in Figures 2 and 4, the notch is provided only in the third layer 30, but this is not limited to this, and a notch of the same shape may be provided in the second layer 20 or the first layer 10 directly above the notch.

[0031] [How to clean printed circuit boards] FIG. 5 is a flow chart showing a method for cleaning a printed circuit board.

[0032] First, a printed circuit board 70 having at least one of a first electronic component 80 and a second electronic component 81 mounted on its surface is prepared (step S1).

[0033] Next, the jig 40 impregnated with the cleaning liquid is prepared (step S2). In step S2, the jig 40 is immersed in the cleaning liquid so that at least the third layer 30 absorbs the cleaning liquid. At this time, the second layer 20 may absorb the cleaning liquid.

[0034] Next, the jig 40 is brought into contact with the surface of the printed circuit board 70 (step S3). Specifically, the third layer 30 impregnated with the cleaning liquid is brought into contact with the surface of the printed circuit board 70. Furthermore, the jig 40 is pressed against the surface of the printed circuit board 70 with a first pressure.

[0035] In this state, a current is passed through the heating wire 11 to heat it up, so that the temperature of the jig 40 becomes a first temperature (step S4). Here, the first temperature is a temperature higher than the temperature at which the flux 90 melts. However, the first temperature needs to be set low enough not to damage the electronic components, the printed circuit board 70, and the jig 40 itself. Usually, the first temperature is set appropriately within the range of room temperature, for example, 15°C or higher and lower than 100°C.

[0036] During the execution of step S4, the third layer 30 that has absorbed the cleaning liquid is heated to the first temperature and comes into contact with the flux 90. During this process, the cleaning liquid is pushed out and adheres to the flux 90. In addition, the flux 90 melts, and most of the melted flux 90 is absorbed by the third layer 30.

[0037] Next, after the jig 40 is removed from the surface of the printed circuit board 70, it is determined whether or not a predetermined amount of flux 90 remains on the surface (step S5). The determination in step S5 may be made visually by an operator who cleans the printed circuit board 70. Alternatively, the surface of the cleaned printed circuit board 70 may be imaged by an imaging device such as a camera (not shown), and the image may be read into a predetermined determination program to determine whether or not the flux 90 remains.

[0038] If the judgment result of step S5 is positive, that is, if it is judged that a predetermined amount or more of flux 90 remains on the surface of the printed circuit board 70, the process returns to step S3, and steps S3 and S4 are repeatedly executed in sequence until the judgment result of step S5 becomes negative.

[0039] If the result of the determination in step S5 is negative, that is, if it is determined that the flux 90 does not remain on the surface of the printed circuit board 70 in a predetermined amount or more, the foreign matter remaining on the surface of the printed circuit board 70, in this case particles, is removed by air blowing (step S6). Furthermore, if necessary, the surface of the printed circuit board 70 is cleaned with a cleaning liquid.

[0040] Next, the printed circuit board 70 is held at the second temperature for a predetermined time (step S7). Here, the second temperature is a temperature at which the cleaning liquid, which is an organic solvent, evaporates, and is usually set to a temperature range equal to or lower than the first temperature. In this way, the cleaning liquid is removed from the surface of the printed circuit board 70, and cleaning of the printed circuit board 70 is completed.

[0041] [Effects, etc.] As described above, the jig 40 according to this embodiment is a cleaning jig for a printed circuit board 70 (substrate 70) on which electronic components are mounted. The jig 40 includes a laminate in which a first layer 10, a second layer 20, and a third layer 30 are laminated in this order.

[0042] The first layer 10 has therein a heating wire 11 which is a heating element. The second layer 20 is deformed by a predetermined amount or more when pressed with a first pressure in the stacking direction of the laminate described above. The third layer 30 is configured to absorb and retain a cleaning liquid for cleaning the printed circuit board 70. The third layer 30 which has absorbed the cleaning liquid comes into contact with the surface of the printed circuit board 70 and cleans the surface.

[0043] According to this embodiment, the flux 90 attached to the surface of the printed circuit board 70 can be efficiently removed regardless of the state of attachment of the flux 90 or the type of electronic components mounted.

[0044] Specifically, the third layer 30 is brought into close contact with the surface of the printed circuit board 70, and the jig 40 is pressed in the stacking direction of the laminate, so that the cleaning liquid held in the third layer 30 is supplied to the surface of the printed circuit board 70. This makes it possible to efficiently remove the flux 90 adhering to the surface of the printed circuit board 70.

[0045] In order to efficiently absorb and discharge the cleaning liquid, the third layer 30 is preferably made of a porous material.

[0046] In addition, by making the second layer 20 have a structure that deforms by a predetermined amount or more when the first pressure is applied, even if the surface of the printed circuit board 70 has unevenness of a predetermined height, the surface of the third layer 30 can be abutted against the recess. This allows the flux 90 to be efficiently removed even if it is attached to the recess. In other words, the second layer 20 is preferably configured to absorb the unevenness of the surface when the laminate is pressed against the surface of the printed circuit board 70 with the first pressure. In the example shown in FIG. 2, the second layer 20 is preferably configured to absorb the height H2, which is the sum of the thicknesses of the wiring 72 and the solder resist 73.

[0047] Furthermore, by providing the first layer 10 with the heating wire 11, which is a heating element, the temperature of the jig 40 can be easily set to the first temperature at which the flux 90 melts. Moreover, since the first layer 10 and the third layer 30 are arranged with the second layer 20 sandwiched therebetween, the cleaning liquid absorbed in the third layer 30 can be prevented from being excessively heated. This makes it possible to prevent the cleaning liquid absorbed in the third layer 30 from evaporating during cleaning.

[0048] In addition, since the amount of heat generated can be changed according to the applied power, as shown in this embodiment, the heat generating element included in the first layer 10 is preferably a resistor such as a heating wire 11 that generates heat when power is applied from the outside. Note that the heating wire 11 is not limited to an electric wire such as a nichrome wire, and may be, for example, a carbon heater or a resistor formed by patterning a carbon sheet.

[0049] Moreover, according to this embodiment, compared to the conventional configuration disclosed in Patent Document 1, expensive equipment such as an ultrasonic cleaner is not required. Also, since a cleaning tank that stores a predetermined amount of cleaning liquid is not required, the amount of cleaning liquid used can be significantly reduced. As a result, the cost of cleaning the printed circuit board 70 can be reduced.

[0050] Also, damage to the printed circuit board 70 and electronic components can be prevented during ultrasonic cleaning. Furthermore, since damage due to ultrasonic vibration is not caused, the wiring 72 of the printed circuit board 70 and the electronic components can be soldered together at the same time. Furthermore, since it is not necessary to immerse the electronic components in a cleaning solvent, the wiring 72 of the printed circuit board 70 and the electronic components can be soldered together and simply.

[0051] Furthermore, when the second electronic component 81 is mounted on the surface of the printed circuit board 70, it is preferable that at least the third layer 30 is shaped so as not to come into contact with the second electronic component 81. Note that the second electronic component 81 is an electronic component whose normal operation may be hindered by the adhesion of cleaning fluid.

[0052] In this way, it is possible to prevent the cleaning liquid from adhering to the second electronic component 81 during cleaning of the printed circuit board 70. This makes it possible to remove the flux 90 adhering to the surface of the printed circuit board 70 while ensuring the operation of the second electronic component 81.

[0053] Note that flux 90 may also be attached between the second electronic component 81 and the surface of the printed circuit board 70. However, when the laminate is pressed, the cleaning liquid flowing out from the third layer 30 reaches a predetermined distance along the surface of the printed circuit board 70. The flux 90 dissolved by the cleaning liquid also flows along the surface of the printed circuit board 70. By appropriately setting the distance between the third layer 30 and the second electronic component 81 along the surface of the printed circuit board 70, the flux 90 attached between the second electronic component 81 and the surface of the printed circuit board 70 can be removed.

[0054] The locations where the flux 90 is attached are generally limited to the connection locations between the electronic components and the wiring 72. Therefore, the third layer 30 may be in contact only with the connection locations between the first electronic components 80 and the wiring 72 and a predetermined area around them. In this manner, it is possible to prevent the cleaning liquid from adhering to unnecessary locations, and it is possible to shorten the time required to remove the cleaning liquid.

[0055] Incidentally, by forming only the third layer 30 in a shape that does not abut against the second electronic component 81, the following advantages are obtained.

[0056] The size, position, and number of second electronic components 81 mounted on printed circuit board 70 are changed as appropriate according to the specifications of the electronic circuit configured on printed circuit board 70. On the other hand, printed circuit board 70 usually has only a few different sizes.

[0057] Therefore, when matching the shapes of the first layer 10 and the second layer 20 with the shape of the third layer 30, it is necessary to prepare multiple types of jigs 40 according to the size, position, and number of second electronic components 81 to be mounted on the printed circuit board 70. However, this requires a lot of man-hours and costs.

[0058] Meanwhile, as described above, the first to third layers 10, 20, 30 in the laminate are configured to be detachable from one another. Therefore, multiple types of only the third layer 30 are prepared according to the size, position, and number of second electronic components 81 to be mounted on the printed circuit board 70. Meanwhile, by making the first layer 10 and the second layer 20 have a common shape regardless of the shape of the third layer 30, an increase in the number of steps and costs required for preparing the jig 40 can be suppressed.

[0059] From this viewpoint, it is preferable that at least the third layer 30 is detachable from the laminate. Furthermore, after cleaning of the printed circuit board 70, the third layer 30 absorbs the dissolved flux 90. After cleaning, the third layer 30, or the second layer 20 and the third layer 30, or the entire jig 40 is immersed in a cleaning solution to remove the flux 90 that has adhered to the jig 40, so that the flux 90 does not reattach in the next cleaning.

[0060] However, if cleaning is performed multiple times, it may not be possible to completely remove the flux 90 from the third layer 30. In such a case, the third layer 30 is separated from the laminate, replaced with a new one, and then reattached to the laminate. In this way, it is possible to prevent the flux 90 from reattaching during cleaning, and it is possible to efficiently remove the flux 90 from the surface of the printed circuit board 70.

[0061] In addition, by making the first to third layers 10, 20, 30 detachable from each other, even if the heating wire 11 of the first layer 10 breaks or the second layer 20 is damaged, they can be easily replaced to repair the jig 40. This makes it possible to prevent an increase in the number of steps and costs required for preparing the jig 40.

[0062] The method for cleaning a printed circuit board 70 according to this embodiment (hereinafter sometimes simply referred to as a board cleaning method) is a board cleaning method using a jig 40, and includes at least the following first to sixth steps.

[0063] In the first step (step S1 in FIG. 5), a printed circuit board 70 having electronic components mounted on its surface is prepared.

[0064] In the second step (step S2 in FIG. 5), at least the third layer 30 of the jig 40 is caused to absorb the cleaning liquid. The second layer 20 of the jig 40 may also be caused to absorb the cleaning liquid.

[0065] In a third step (step S3 in FIG. 5), after the second step is performed, the surface of the printed circuit board 70 is pressed with the jig 40 while the third layer 30 is in contact with the surface of the printed circuit board 70.

[0066] In a fourth step (step S4 in FIG. 5), after the third step is performed, the heating wire 11, which is a heating element, is caused to generate heat so as to reach the first temperature.

[0067] In a fifth step (step S6 in FIG. 5), foreign matter remaining on the surface of the printed circuit board 70 is removed after the jig 40 is removed from the surface of the printed circuit board 70. Furthermore, if necessary, the surface of the printed circuit board 70 is cleaned with a cleaning liquid.

[0068] In a sixth step (step S7 in FIG. 5), after the fifth step is performed, the cleaning liquid is removed from the surface of the printed circuit board 70.

[0069] In this manner, the flux 90 adhering to the surface of the printed circuit board 70 can be efficiently removed regardless of the state of the flux 90 or the type of electronic components mounted.

[0070] It is preferable to further include a seventh step (step S5 in FIG. 5) of determining whether or not a predetermined amount or more of the flux 90 remains on the surface of the printed circuit board 70 after the fourth step is performed.

[0071] If the determination result in the seventh step is negative, the process proceeds to the fifth step, and if the determination result in the seventh step is positive, the third step and the fourth step are repeatedly executed until the determination result becomes negative.

[0072] In this way, the flux 90 adhering to the surface of the printed circuit board 70 can be reliably removed.

[0073] In the fifth step, gas, in this case air, may be blown onto the surface of the printed circuit board 70 at a predetermined flow rate and pressure to remove foreign matter. In this way, foreign matter can be removed without scrubbing the printed circuit board 70. If scrubbing is performed, a load is applied to the connection points between the wiring 72 of the printed circuit board 70 and the electronic components, which may adversely affect the reliability of the connection points. In addition, if the solder resist 73 is partially peeled off and the wiring 72 is exposed, this may adversely affect the operation of the electronic circuit configured in the printed circuit board 70. According to this embodiment, it is possible to prevent these concerns from occurring.

[0074] In the present embodiment, the cleaning liquid is an organic solvent, and therefore, in the sixth step, the printed circuit board 70 is maintained at the second temperature described above, thereby evaporating the organic solvent from the surface of the printed circuit board 70.

[0075] In this manner, the surface of the printed circuit board 70 can be cleaned without adversely affecting the printed circuit board 70 or the electronic components mounted thereon.

[0076] In addition, if the organic solvent is not easily evaporated by heating but can be removed with pure water, the organic solvent can be removed as described below instead of step S7 (sixth step) in FIG.

[0077] Fig. 6 is a flow chart showing another method for cleaning a printed circuit board. Note that steps S11 to S16 in Fig. 6 are similar to steps S1 to S6 in Fig. 5, and therefore a description thereof will be omitted.

[0078] Following step S16, another jig (not shown) is further prepared, and this other jig is impregnated with pure water (step S17). Furthermore, the printed circuit board 70 is sandwiched between this jig, thereby removing the organic solvent from the surface of the printed circuit board 70 (step S18).

[0079] The processes of steps S17 and S18 correspond to the sixth step described above. Note that, if necessary, the processes of steps S17 and S18 may be sequentially repeated. Also, the separate jig impregnated with pure water may be brought into contact with only the surface of the printed circuit board 70 to press the surface. From the viewpoint of cleaning the surface of the printed circuit board 70, it is preferable to impregnate the separate jig with pure water, but this is not limiting, and for example, water used industrially for cleaning electronic components, etc. may be used.

[0080] In this manner, the surface of the printed circuit board 70 can be cleaned without adversely affecting the printed circuit board 70 or the electronic components mounted thereon.

[0081] (Embodiment 2) Fig. 7A is a perspective view of the cleaning jig according to embodiment 2 with the exterior open, and Fig. 7B is a perspective view of the cleaning jig according to embodiment 2 with the exterior closed.

[0082] For ease of explanation, in FIGS. 7A and 7B, the same reference numerals are used for the same parts as those in the first embodiment, and detailed explanations thereof will be omitted.

[0083] As described above, the jig 40 holds the laminate in which the first to third layers 10, 20, 30 are stacked, and further includes a component that presses this against the surface of the printed circuit board 70. The structure of this component can be changed as appropriate depending on the size of the printed circuit board 70, etc.

[0084] For example, when the size of the printed circuit board 70 is about several centimeters square, the part may be a holder 50 as shown in FIGS. 7A and 7B.

[0085] 7A and 7B includes the above-mentioned jig 40 and holder 50. Holder 50 includes two exterior parts 51, two arms 52, and a fixing mechanism 53, and the two exterior parts 51 are connected to each other by a hinge. Each of the two exterior parts 51 has a recess, and as shown in Fig. 7A, jig 40 and a printed circuit board 70 abutted against the third layer 30 of the jig are disposed in the recess of one of the exterior parts 51.

[0086] One end of each of the two arms 52 is connected to each of the divided parts of the two exteriors 51. By manipulating the other ends of each of the two arms 52 to move closer to each other, the two exteriors 51 move closer to each other and close with the hinges as the connecting axis.

[0087] The fixing mechanism 53 is a kind of hook that is provided to fix the state after the two exterior parts 51 are closed.

[0088] The fixing mechanism 53 is attached to the other end of one of the two arms 52. After the two arms 52 are moved toward each other to close the two exterior parts 51, the fixing mechanism 53 is attached by hooking it onto the other end of the other of the two arms 52, generating a tightening force that moves the two arms 52 toward each other. As a result, the two exterior parts 51 are fixed in a closed state.

[0089] That is, by operating the two arms 52 and closing the two exteriors 51, the jig 40 can be pressed against the surface of the printed circuit board 70 with a predetermined pressure. The clamping force of the fixing mechanism 53 is set so that this pressure becomes the first pressure. In other words, the third step described above is executed.

[0090] In this state, when a current is applied from the wiring 41 to the heating wire 11, the heating wire 11 generates heat, and the temperature of the jig 40 becomes the first temperature. That is, the above-mentioned fourth step is executed.

[0091] After a predetermined time has elapsed, the fixing mechanism 53 is removed from the other end of the two arms 52 to open the two exteriors 51, and it is confirmed whether or not a predetermined amount or more of the flux 90 remains on the surface of the printed circuit board 70. In other words, the above-mentioned seventh step is executed.

[0092] As described above, the mechanism for holding the jig 40 and pressing the jig 40 against the surface of the printed circuit board 70 is not particularly limited to the one shown in this embodiment. [Industrial Applicability]

[0093] The cleaning tool of the present disclosure is useful because it can efficiently remove flux adhering to the surface of a printed circuit board, regardless of the state of the flux or the type of electronic components mounted thereon. [Explanation of symbols]

[0094] 10 1st layer 11 Heating wire (heating element, resistor) 20 2nd layer 30 3rd layer 40 Jig (cleaning jig) 50 Holder 51 Exterior 52 Arm 53 Fixing mechanism 60 Jig (cleaning jig) 70 Printed circuit board (circuit board) 71 Main Board 72 Wiring 73 Solder resist 80 First Electronic Component (Electronic Component) 81 Secondary Electronic Components (Electronic Components) 90 Flux

Claims

1. A cleaning tool for a substrate on which electronic components are mounted, comprising: The laminate includes a first layer, a second layer, and a third layer stacked in this order, The first layer has a heating element therein, the second layer is deformed by a predetermined amount or more by being pressed with a first pressure in a stacking direction of the first to third layers, The cleaning tool, wherein the third layer is configured to absorb and retain inside a cleaning liquid for cleaning the substrate.

2. The cleaning tool according to claim 1 , The heating element is a resistor that generates heat when power is applied from an external source, the second layer is configured to absorb irregularities in the surface when the laminate is pressed against the surface of the substrate with the first pressure; The cleaning tool, wherein the third layer is made of a porous material.

3. The cleaning tool according to claim 1 , A cleaning tool, characterized in that the third layer comes into contact with the surface of the substrate to clean the surface.

4. The cleaning tool according to claim 3, When a second electronic component is mounted on the surface, At least the third layer is shaped so as not to come into contact with the second electronic component, The cleaning tool according to claim 1, wherein the second electronic component is at risk of being prevented from functioning normally by the adhesion of the cleaning liquid thereto.

5. The cleaning tool according to claim 3, The cleaning tool further comprises a holder for holding the laminate.

6. The cleaning tool according to any one of claims 1 to 5, A cleaning tool, wherein at least the third layer is detachable from the laminate.

7. A substrate cleaning method using the cleaning jig according to claim 6, comprising the steps of: A first step of preparing a substrate having electronic components mounted on a surface thereof; a second step of allowing at least the third layer to absorb the cleaning solution; a third step of pressing the surface with the cleaning tool while the third layer is in contact with the surface after the second step is performed; a fourth step of heating the heating element to a first temperature after the third step is performed; a fifth step of removing foreign matter remaining on the surface after the cleaning tool is removed from the surface, and further cleaning the surface with the cleaning liquid; a sixth step of removing the cleaning liquid from the surface after the fifth step is performed.

8. 8. The method for cleaning a substrate according to claim 7, A seventh step of determining whether or not a predetermined amount of flux remains on the surface after the fourth step is performed, If the result of the determination in the seventh step is negative, proceed to the fifth step; a step of repeatedly executing the third and fourth steps until the seventh step determines whether the seventh step is positive or negative, the step of repeatedly executing the third and fourth steps until the seventh step determines whether the seventh step is negative or negative.

9. 8. The method for cleaning a substrate according to claim 7, A substrate cleaning method, wherein in the fifth step, a gas is blown onto the surface to remove the foreign matter.

10. 8. The method for cleaning a substrate according to claim 7, The cleaning liquid is an organic solvent, The sixth step of the present invention relates to a method for cleaning a substrate, and more particularly to a method for cleaning a substrate, the method comprising the steps of: maintaining the substrate at a second temperature to evaporate the organic solvent from the surface of the substrate;

11. 8. The method for cleaning a substrate according to claim 7, The cleaning liquid is an organic solvent that is not easily evaporated by heating, a sixth step of pressing at least the surface of the substrate with pure water or another jig impregnated with water, thereby removing the organic solvent from the surface of the substrate;

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