KR101359605B1 - Surface mount technology system - Google Patents

Abstract

The present invention discloses an SMT system for removing the oxide film generated on the surface of the electrode of the surface mount device before mounting the surface mount device. SMT system of the present invention, the surface mounting element supply tray unit; A mounter unit which absorbs surface mount elements from the tray unit and mounts them on a printed circuit board; A camera unit for recognizing suction position information of the surface mount element and each electrode position information of the surface mount element adsorbed by the mounter unit; A laser unit for removing an oxide film on the surface of the electrode by irradiating a laser beam to the electrodes of the surface mount device; And a control unit which receives the electrode position information of the surface mounting element from the camera unit and controls the laser beam irradiation position of the laser unit.

SMT, SMD, Surface, Mount, Electrode, Lead, Bump, Oxide, Remove, Galvano, Mirror, Laser Beam

Description

SMT system {SURFACE MOUNT TECHNOLOGY SYSTEM}

The present invention relates to an SMT, and more particularly, to an SMT system having a laser unit for irradiating a laser beam for removing an oxide film generated on an electrode (lead) of a surface mount element (SURFACE MOUNT DEVICE).

As is well known, SMT equipment prints solder on the land of the printed circuit board, and then mounts the lead of the surface mount device on the land where the solder is printed, and applies infrared radiation to the printed circuit board on which the surface mount device is mounted. It is a device that melts and pastes the solder to connect the leads of the surface mount device and the lands of the printed circuit board.

In the above-described mounting technology, the oxide film generated on the lead surface of the surface mounting element or the land surface of the printed circuit board is the biggest factor that impairs solderability. In order to remove such an oxide film, an activator is added to the flux of the solder paste. The activator is activated when heated to dissolve and remove the oxide film.

However, in view of global environmental conservation, since the Freon, which has been used for cleaning residual flux on the surface of a printed circuit board, cannot be used, RA (Resin Active), which is highly active and highly corrosive, requires cleaning of the active agent remaining. In the) type flux, the transition to the low activity flux of the RMA (Resin Mildly Active) type which has weak activity but does not cause corrosion or migration to the wiring of the printed circuit board has been progressed even in the no-clean. Thereby, the oxide film removal ability of an active agent falls and solderability deteriorates.

In addition, the transition to lead-free solders without solder having good solderability is also progressing, and solderability is further deteriorated by these. The melting point of the lead-free solder is about 220 degrees, which is more than 30 degrees higher than that of 183 degrees of general solders (63% Sn and 37% Pb), which is a deterioration of solderability. .

On the other hand, when the solder paste is heated in the surface mounting of the electronic component, the activator contained in the flux activates with the temperature rise, thereby dissolving and removing the oxide film, thereby enabling soldering. However, on the other hand, the reaction progress rate of the activator is also accelerated with the rise in temperature, and the active life is shortened by deterioration of the activator. For this reason, if heating time is long until reaching the oxide film removable temperature, sufficient activity will not remain when the oxide film removable temperature is reached after that. The transition to the lead-free solder having a high melting point is to deteriorate the flux activator, which has already become less active due to the transition to RMA, to a high temperature for a further time, which also deteriorates the solderability.

SUMMARY OF THE INVENTION The present invention has been devised in view of the above, and the problem to be solved by the present invention is that the oxide film on the surface of the surface mount element electrode (lead), which is a factor that lowers the solderability, can be removed before the surface mount element is mounted. To provide an SMT system.

According to an aspect of the present invention for solving the above problems, SMT system, the surface mounting element supply tray unit; A mounter unit which absorbs surface mount elements from the tray unit and mounts them on a printed circuit board; A camera unit for recognizing suction position information of the surface mount element and each electrode position information of the surface mount element adsorbed by the mounter unit; A laser unit for removing an oxide film on the surface of the electrode by irradiating a laser beam to the electrodes of the surface mount device; And a control unit which receives the electrode position information of the surface mounting element from the camera unit and controls the laser beam irradiation position of the laser unit.

The control unit includes: laser beam irradiation angle changing means installed in the laser beam path of the laser unit to change the irradiation angle of the laser beam; And a controller for controlling driving of the laser beam irradiation angle changing means.

In addition, the laser beam irradiation angle changing means may include a galvano-mirror in which the angle is changed linearly according to the change of the input voltage.

In addition, the SMT system according to an aspect of the present invention, the laser beam irradiation angle correction lens installed in the laser beam path between the laser beam irradiation angle changing means and the surface-mounting device to correct the laser beam irradiation angle It may further include.

The laser beam irradiation angle correcting lens may include an f-θ lens.

In addition, the SMT system according to an aspect of the present invention may further include an attenuator installed in the laser beam path to adjust the energy density of the laser beam.

The attenuator may be movable between the laser unit and the galvano-mirror, and may include an optical mask having a plurality of laser beam passing holes having different sizes.

Further, a first concave lens for enlarging the diameter of the laser beam between the optical mask and the laser unit and a first convex lens for passing the laser beam whose diameter is enlarged by the first concave lens to the optical mask as parallel light. And a second convex lens for condensing the laser beam passing through the optical mask and a laser beam focused by the second convex lens between the optical mask and the galvano-mirror to return to parallel light. The second concave lens may be disposed.

In addition, the optical mask may be installed to be movable between the laser beam irradiation angle correction lens and the surface mount element.

According to another aspect of the present invention for solving the above problems, SMT system, the surface mounting element supply tray unit; A mounter unit which absorbs surface mount elements from the tray unit and mounts them on a printed circuit board; A moving unit which moves the mounter unit in the X / Y direction; A camera unit for recognizing suction position information of the surface mount element and each electrode position information of the surface mount element adsorbed by the mounter unit; A laser unit for removing an oxide film on the surface of the electrode by irradiating a laser beam to the electrodes of the surface mount device; And a control unit which receives the electrode position information of the surface mounting element from the camera unit and controls the driving of the mobile unit so that the electrode to be processed is positioned at the laser beam irradiation position of the laser unit.

In addition, the SMT system according to another aspect of the present invention may further include an attenuator installed in the laser beam path of the laser unit to adjust the energy density of the laser beam.

The attenuator may include an optical mask having a plurality of laser beam passing holes having different sizes.

Between the optical mask and the laser unit is disposed a first concave lens for enlarging the diameter of the laser beam and a first convex lens for passing the laser beam enlarged in diameter by the first concave lens to the optical mask in parallel light. And a second convex lens for condensing the laser beam passing through the optical mask between the optical mask and the surface mounting element, and a second concave for returning the laser beam focused by the second convex lens to parallel light. The lens can be placed.

According to the SMT system of the present invention, since the oxide film on the surface of the electrode before mounting of the surface mount element is removed, it is possible to realize a good soldering quality without being affected by the characteristics of the solder paste activator.

In addition, according to the SMT system of the present invention, since the mount is performed immediately after the oxide film on the electrode surface is removed, the time for contacting the electrode with air can be shortened, and the progress of reoxidation of the electrode can be suppressed.

In addition, according to the SMT system of the present invention, since the laser unit can be configured using the parts supply mechanism, the driving system, the image processing system, and the like of the existing SMT system, it is possible to implement the SMT system with significantly improved solderability at low cost.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 to 4 are diagrams for explaining an SMT system according to an embodiment of the present invention. As shown in Figure 1, the SMT system according to an embodiment of the present invention, the surface mounting element supply tray unit 10, the mounter unit 20, the camera unit 30, the laser unit 40 and control The unit 50 is provided. In addition, the SMT system according to an embodiment of the present invention is a solder printer unit for printing a solder on the connection pattern (land) of the printed circuit board 2 on which the surface mounting element 1, the surface mounting element (1) A transfer unit for transferring the mounted printed circuit board 2, and a reflow soldering unit and an unloader unit for applying soldering by applying infrared radiation to the printed circuit board 2 carried by the transfer unit are provided. The illustration and description are omitted because they are not highly relevant to the gist of the invention.

The surface mount element supplying tray unit 10 accommodates a plurality of surface mount elements 1. The surface mount devices 1 include a plurality of electrodes (leads) protruding to the outside of the device (not shown) and a plurality of electrodes 1a disposed on the bottom surface of the device 1 in an array form. It refers to an electronic component such as a transistor, a diode, a resistor, an IC chip, etc., in which the electrodes of the device are soldered to the surface of the printed circuit board.

The mounter unit 20 mounts the surface mount device 1 on the printed circuit board 2 by absorbing one surface mounting element 1 from the tray unit 10, and includes a vacuum adsorption nozzle. The mounter unit 20 includes a printed circuit board in which the tray unit 10 first adsorbs the surface mount element 1 and the adsorbed surface mount element 1 is positioned adjacent to the tray unit 10. It is movable between the 2nd positions mounted in (2). Further, the mounter unit 20 corrects the adsorption position distortion of the surface mount element 1 and the electrode 1a at approximately the center between the first position and the second position (referred to as the third position for convenience of description). Temporarily stop for surface treatment.

The camera unit 30 photographs the surface mount element 1 under the surface mount element 1 when the mounter unit 20 that has adsorbed the surface mount element 1 pauses at a third position. . Based on the image information photographed by the camera unit 30, the main controller (not shown) of the system recognizes the adsorption position of the surface mount device 1 and corrects the misalignment when it is determined that the adsorption position is misaligned. At this time, the SMT system according to an embodiment of the present invention recognizes the positional information of each electrode 1a of the surface mount element 1 in addition to the adsorption position misalignment information of the surface mount element 1. This will be described later.

The laser unit 40 irradiates a laser beam to the electrodes 1a of the surface mounting element 1 to remove the oxide film on the surface of the electrode 1a when the mounter unit 20 temporarily stops at the third position. do. At this time, it is necessary to make the laser beam irradiate only the electrode 1a of the surface mounting element 1.

The control unit 50 receives the electrode position information of the surface mounting element 1 from the camera unit 30 and controls the laser beam irradiation position of the laser unit 40. That is, the control unit 50 controls the irradiation position of the laser beam differently according to the electrode position information so that the laser beam is sequentially irradiated to the electrodes 1a of the surface mounting element 1.

The control unit 50 as described above is installed in the laser beam path of the laser unit 40, the laser beam irradiation angle changing means 51 and the laser beam irradiation angle changing means 51 for changing the irradiation angle of the laser beam. The control part 52 which controls the drive of the is provided. As the laser beam irradiation angle changing unit 51, a galvanometer-mirror may be used in which the angle is changed linearly according to the change of the input voltage. However, the laser beam irradiation angle changing unit 51 is not limited thereto. Any mirror can be used as long as the structure is changeable.

2a and 2b shows that the irradiation position of the laser beam is changed according to the driving of the galvano-mirror 51 according to an embodiment of the present invention. In FIG. 2A, the galvano-mirror 51 is inclined at about 45 degrees, and thus the laser beam L1 is irradiated to the first electrode 1a 'of the surface mount element 1. 2B shows that the galvano-mirror 51 is inclined at about 120 degrees, and thus the laser beam L2 is irradiated to the second electrode 1a "of the surface mounting element 1. As described above, the electrode By changing the angle of the galvano-mirror 51 according to the position of (1a ', 1a "), the laser beam irradiation to the corresponding electrode 1a' or 1a" becomes possible.

On the other hand, when irradiating a laser beam to each electrode 1a ', 1a "of the surface mounting element 1, while changing the irradiation angle of a laser beam using the galvano-mirror 51 as described above, a galvano- According to the angle of the mirror 51, in the case of the bump-type electrode, the laser beam is irradiated to only a part of the electrode, so that the oxide film on the surface of the electrode may not be completely removed. May need to adjust the energy density of the laser beam.

Figure 3 schematically shows an SMT system according to an embodiment of the present invention configured in view of the above points. According to FIG. 3, an SMT system according to an embodiment of the present invention includes a laser beam irradiation angle correcting lens for correcting an irradiation angle of a laser beam between a galvano-mirror 51 and a surface mounting element 1. 60) is installed. An f-θ lens may be used as the laser beam irradiation angle correcting lens 60. The f-θ lens allows the laser beam whose irradiation angle is changed by the galvano-mirror 51 to be irradiated to the entire surface of the bump-type electrode, for example, so that the laser beam is not irradiated to only a part of the electrode. The oxide film on the surface can be completely removed.

In addition, according to FIG. 3, an SMT system according to an embodiment of the present invention includes an attenuator for adjusting an energy density of a laser beam between the laser beam irradiation angle correcting lens 60 and the surface mount device 1. An attenuator 70 is provided. The attenuator 70 is movably installed in the laser beam path, and is composed of an optical mask having a plurality of laser beam through holes 71 having different sizes. The energy density of the laser beam is appropriately adjusted by the plurality of laser beam through holes 71 having different sizes of the optical mask, and is irradiated to the electrode 1a of the surface mounting element 1. That is, the energy density of the laser beam passing through the small laser beam through hole 71 "is smaller than that of the laser beam passing through the large laser beam through hole 71 '. Thus, the surface of the surface mounting element electrode According to the oxide film situation, by selecting the through hole 71 through which the laser beam passes by moving the optical mask, a laser beam having an appropriate energy density can be irradiated to the electrode.

In addition, in the SMT system according to an embodiment of the present invention, the attenuator 70 may be disposed between the laser unit 40 and the galvano-mirror 51, as shown in FIG. The attenuator 70 is configured in the same manner as in FIG. 3. However, referring to FIG. 4, between the attenuator 70 and the laser unit 40, the first concave lens 81 and the first concave lens 81 which enlarge the diameter of the laser beam to lower the energy density are provided. The first convex lens 82 is arranged to pass the laser beam, the diameter of which is expanded, to the laser beam passing hole 71 of the attenuator 70 as parallel light. In addition, between the attenuator 70 and the galvano-mirror 51, a second convex lens for condensing the laser beam passing through the laser beam passing hole 71 of the attenuator 70 to the required energy density. (83) and a second concave lens (84) for returning the laser beam collected by the second convex lens (83) to parallel light are arranged. According to such a structure, the damage of the attenuator 70, ie, the optical mask, can be reduced.

As shown in FIG. 3, when the attenuator 70 is disposed between the f-θ lens 60 and the surface mounting element 1, the optical system is not complicated, but the laser beam passing hole 71 of the attenuator 70 is provided. Since the attenuator 70 needs to be driven in accordance with the drive for selection and the laser beam irradiation position is changed each time, the position control is complicated. However, as shown in Fig. 4, when the attenuator 70 is disposed between the laser unit 40 and the galvano-mirror 51, the control is simple, but as mentioned above, the damage of the optical mask is avoided. In order to do this, the first and second concave lenses 81 and 84, the first and second convex lenses 82 and 83, and the like are provided before and after the optical mask, thereby making it optically complicated.

5 is a view schematically showing an SMT system according to another embodiment of the present invention. As shown in FIG. 5, the configuration of the SMT system according to the present embodiment is not significantly different from the above-described embodiment. However, in the present embodiment, as the means for controlling the irradiation position of the laser beam, the mounter unit is adopted by employing a moving unit 90 for moving the mounter unit 20 in the X / Y direction without using a galvano-mirror. 20 was moved in the X / Y direction so that the laser beam was sequentially irradiated to the corresponding electrode 1a of the surface mounting element 1.

According to this embodiment, the laser beam is always irradiated almost perpendicularly to the electrode 1a of the surface mount element 1, and the corresponding electrode 1a is moved while the surface mount element 1 moves in the X / Y direction. Since it moves to the laser beam irradiation position, there is no need to separately install a laser beam irradiation angle correction lens as in one embodiment. However, the attenuator 70 mentioned in one embodiment may be provided.

On the other hand, in the SMT system according to various embodiments of the present invention as described above, in the case where there is interference between the camera unit and the laser beam path, the position where the surface mount element is off-set after image processing of the surface mount element 1. And to perform an oxide film removing process. According to this, the mounter unit can perform the adsorption of the other surface mount element while the oxide film of one surface mount element is removed.

In the SMT system according to the embodiment of the present invention as described above, the mounter unit 20 absorbs one surface mount element 1 accommodated in the surface mount element supply tray unit 10 and moves to the third position. At this time, the suction position twist information and the position information of each electrode 1a are grasped by the camera unit 30.

Among the above information, information such as suction position twist and the like is input to the main controller and used to correct the twist, and position information of each electrode is input to the controller 52 and used to control the irradiation position of the laser beam.

That is, according to the electrode position information input to the controller 52, the controller 52 drives the galvano-mirror 51 or the mobile unit 90 to determine the processing position of each electrode, in turn, each electrode. The oxide film is removed by irradiating the surface with a laser beam.

After that, the surface mount element 1 from which the oxide film of the electrode is removed is mounted on the printed circuit board 2 according to the operation of the conventional SMT system. Since the oxide film was removed from the surface of the electrode of the surface mount device mounted in this manner, even in the surface mount device in which a strong oxide film was formed until soldering with an RMA type solder paste or immediately before the laser beam treatment according to the present invention. Good solderability can be realized, and in particular, generation of cold solder or the like, which has become a problem recently, can be prevented.

The present invention has been described above by way of example. The terms used herein are for the purpose of description and should not be construed as limiting. Various modifications and variations of the present invention are possible in light of the above teachings. Accordingly, the invention may be freely practiced within the scope of the claims unless otherwise stated.

1 is a view schematically showing an SMT system according to an embodiment of the present invention;

2a and 2b are views showing an example in which the laser beam irradiation angle is changed by the galvano-mirror in the SMT system shown in FIG.

3 is a view illustrating a main configuration of an SMT system according to an embodiment of the present invention having a laser beam irradiation angle correcting lens and an attenuator;

4 is a view showing the main configuration of the SMT system according to an embodiment of the present invention with different positions of the attenuator, and

5 is a view schematically showing an SMT system according to another embodiment of the present invention.

Description of the Related Art

1; surface-mount element 1a, 1a ', 1a "; electrode

2; printed circuit board 10; tray unit

20; mounter unit 30; camera unit

40; laser unit 50; control unit

51; laser beam irradiation angle changing means (galvano mirror)

52; controller 60; laser beam irradiation angle correction lens

70; Attenuator (Optical Mask) 71, 71 ', 71 "; Laser Beam Through Hole

81,84; concave lens 82,83; convex lens

90; mobile unit

Claims (13)

A tray unit for supplying a surface mount element; A mounter unit which absorbs surface mount elements from the tray unit and mounts them on a printed circuit board; A camera unit for recognizing suction position information of the surface mount element and each electrode position information of the surface mount element adsorbed by the mounter unit; A laser unit for removing an oxide film on the surface of the electrode by irradiating a laser beam to the electrodes of the surface mount device; And And a control unit which receives the electrode position information of the surface mounting element from the camera unit and controls the laser beam irradiation position of the laser unit. The control unit includes: Laser beam irradiation angle changing means installed in the laser beam path of the laser unit to change the irradiation angle of the laser beam; And And a control unit for controlling the driving of the laser beam irradiation angle changing means. delete The method of claim 1, The laser beam irradiation angle changing means comprises a galvano-mirror that changes the angle linearly with the change of the input voltage. The method of claim 1, And a laser beam irradiation angle correcting lens for correcting an irradiation angle of a laser beam in a laser beam path between the laser beam irradiation angle changing means and the surface mount element. 5. The method of claim 4, And the laser beam irradiation angle correcting lens comprises an f-θ lens. The method of claim 3, wherein And an attenuator installed during the laser beam path to adjust the energy density of the laser beam. The method of claim 6, And the attenuator is disposed between the laser unit and the galvano-mirror and includes an optical mask having a plurality of laser beam through holes having different sizes. The method of claim 7, wherein Between the optical mask and the laser unit is disposed a first concave lens for enlarging the diameter of the laser beam and a first convex lens for passing the laser beam enlarged in diameter by the first concave lens to the optical mask in parallel light. Become, Between the optical mask and the galvano-mirror is arranged a second convex lens for condensing the laser beam passing through the optical mask and a second concave lens for returning the laser beam focused by the second convex lens to parallel light. SMT system. 5. The method of claim 4, And an optical mask movably installed between the laser beam irradiation angle correcting lens and the surface mount device, the plurality of laser beam passing holes having different sizes, the optical mask adjusting the energy density of the laser beam. A tray unit for supplying a surface mount element; A mounter unit which absorbs surface mount elements from the tray unit and mounts them on a printed circuit board; A moving unit which moves the mounter unit in the X / Y direction; A camera unit for recognizing suction position information of the surface mount element and each electrode position information of the surface mount element adsorbed by the mounter unit; A laser unit for removing an oxide film on the surface of the electrode by irradiating a laser beam to the electrodes of the surface mount device; And And a control unit which receives the electrode position information of the surface mounting element from the camera unit and controls the driving of the mobile unit so that the electrode to be processed is positioned at the laser beam irradiation position of the laser unit. 11. The method of claim 10, SMT system further comprises an attenuator installed in the laser beam path of the laser unit to adjust the energy density of the laser beam. The method of claim 11, The attenuator includes an optical mask formed with a plurality of laser beam through-holes of different sizes. 13. The method of claim 12, Between the optical mask and the laser unit is disposed a first concave lens for enlarging the diameter of the laser beam and a first convex lens for passing the laser beam enlarged in diameter by the first concave lens to the optical mask in parallel light. Become, Between the optical mask and the surface mount element, a second convex lens for condensing the laser beam passing through the optical mask and a second concave lens for returning the laser beam focused by the second convex lens to parallel light are disposed. SMT system.

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