JP5071218B2 - Paste transfer apparatus and paste transfer method - Google Patents

Description

  The present invention relates to a paste transfer apparatus and a paste transfer method for transferring a paste to a bump by bringing a bump of a component into contact with a paste film formed to have a constant thickness.

  Conventionally, in a component mounter that mounts a component having a bump (solder bump, gold bump, etc.) formed on the lower surface, such as BGA (Ball Grid Array), on a substrate, before mounting the component on the substrate, A paste transfer device for applying paste to the bumps is provided. The paste applied to the bumps varies depending on the type of the bump. For example, a flux paste (not containing solder particles) is applied to the solder bumps, and a solder paste is applied to the gold bumps.

The paste transfer device leveles the paste by reciprocating the squeegee horizontally in a paste tank installed in the component mounting machine, and pastes the bumps of the components picked up by the suction nozzle onto the paste film of a certain thickness. The paste corresponding to the thickness of the paste film is transferred to the bumps by contacting from above. In addition, when the state of adhesion of the paste to the bump is poor (for example, the spread of the paste on the bump surface is insufficient), the solder wettability is insufficient or the amount of solder is insufficient. Since there is a possibility that a defect may occur, the bump is observed with a camera after the paste is transferred, and it is judged whether the paste is attached to the bump. There is known one in which a warning is issued (Patent Document 1).
JP 2007-305724 A

  However, in the case where a warning is issued when a paste transfer failure occurs as described above, the number of defective products can be reduced by removing the defective component from the board production line, but the paste transfer Yields could not be improved because defective parts could not be converted into good products.

  Therefore, an object of the present invention is to provide a paste transfer device and a paste transfer method that can convert a part that has caused a paste transfer failure to a non-defective product as much as possible and improve the yield.

  The paste transfer device according to claim 1 is a paste transfer device for transferring a paste to a bump by bringing the bump of the component into contact with a paste film formed to a constant thickness, and for the bump after the paste is transferred A surface state detection unit that detects a surface state, a determination unit that determines whether the paste is attached to the bump based on the surface state of the bump detected by the surface state detection unit, A paste film thickness changing unit that changes the thickness of the paste film according to the number of times the paste is transferred to the component of the paste or its components when it is determined that the paste adhesion state is poor, and the paste film thickness changing unit; And a re-transfer executing unit for bringing the component bumps into contact with the paste film whose thickness has been changed by the step and transferring the paste to the bumps again.

The paste transfer device according to claim 2 is the paste transfer device according to claim 1, wherein the paste film thickness changing unit is configured such that when the paste contains solder particles, the number of times the paste is transferred is executed. As the number increases, the thickness of the paste film decreases.

  A paste transfer apparatus according to claim 3 is the paste transfer apparatus according to claim 1 or 2, wherein a colored paste is used.

  The paste transfer method according to claim 4 is a paste transfer method in which a bump of a component is brought into contact with a paste film formed with a constant thickness to transfer the paste to the bump, and the bump is transferred after the paste is transferred. A surface condition detection process for detecting the surface condition, a determination process for determining whether the paste is attached to the bump based on the surface condition of the bump detected in the surface condition detection process, and a bump process in the determination process. A paste film thickness changing step for changing the paste film thickness according to the number of times the paste is transferred to the component or part of the paste when it is determined that the paste adhesion state is poor, and the paste film thickness changing step; And a re-transfer execution step of bringing the component bumps into contact with the paste film whose thickness has been changed and re-transferring the paste to the bumps.

  The paste transfer method according to claim 5 is the paste transfer method according to claim 4, wherein in the paste film thickness changing step, when the paste contains solder particles, the number of times the paste is transferred is As the number increases, the thickness of the paste film decreases.

  A paste transfer method according to claim 6 is the paste transfer method according to claim 4 or 5, wherein a colored paste is used.

  In the present invention, instead of discarding the component in which the transfer failure of the paste has occurred, the paste is re-transferred to the bumps and converted to a non-defective product as much as possible, so that the yield can be improved. . Also, when the paste is retransferred, the thickness of the paste film is changed according to the number of times the paste is transferred to the component of the paste or its components. By re-transferring the paste, it is possible to prevent as much as possible the inconvenience that excessive paste adheres to the bump and a bridge is formed between adjacent electrodes when a component is bonded to the substrate, causing a short circuit. .

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a component mounting machine including a paste transfer device according to an embodiment of the present invention, and FIG. 2 illustrates a mounting procedure of components onto a substrate including an execution procedure of a paste transfer method according to an embodiment of the present invention. FIGS. 3A, 3B, and 3C are explanatory diagrams of the procedure for transferring the paste to the bumps according to the embodiment of the present invention, and FIG. 4 is the bumps of the paste according to the embodiment of the present invention. (A) Side view and (b) Bottom view of part showing adhesion state to FIG. 5, FIG. 5 is a side view of the part showing adhesion state of paste to bump in one embodiment of the present invention.

  In FIG. 1, a component mounter 3 for mounting a component 2 on a substrate 1 includes a paste transfer device according to an embodiment of the present invention, and includes a substrate positioning unit 4 for positioning the substrate 1 and supply of the component 2. Picked up by a parts feeder 5, a paste film forming unit 6 for forming a paste film p of a certain thickness, a component suction moving unit 7 for picking up and moving the component 2 supplied from the part feeder 5, and a component suction moving unit 7 A camera 8 that captures the imaged component 2 from below and a control device 9 that controls the operation thereof are provided.

The substrate positioning unit 4 includes a pair of conveyor belts 10 extending in parallel to one direction in a horizontal plane (a direction orthogonal to the paper surface of FIG. 1) and a conveyor driving mechanism 11 that operates the conveyor belt 10. The conveyor drive mechanism 11 is controlled by the control device 9 to drive the conveyor belt 10, and conveys the substrate 1 placed on the upper surface of the conveyor belt 10 and positions it to a predetermined reference position.

  The parts feeder 5 operates under the control of the control device 9 and supplies the part 2 to a predetermined part supply position. In this embodiment, it is assumed that the component 2 is a BGA type component having a plurality of bumps 2a such as solder bumps and gold bumps on the lower surface (see an enlarged view of the component 2 shown in FIG. 1).

  The paste film forming unit 6 is provided with a paste tank 12 to which the paste P is supplied, a squeegee 13 provided so as to be relatively movable in the horizontal direction with respect to the paste tank 12, and a squeegee operating mechanism for moving the squeegee 13 relative to the paste tank 12. It consists of 14. The squeegee operating mechanism 14 is controlled by the control device 9 to reciprocate the squeegee 13 in the horizontal direction (arrow A shown in FIG. 1), and the paste P in the paste tank 12 is leveled to form a paste film in the paste tank 12. A paste film p having a constant thickness is formed on the surface 12a. Further, the squeegee operating mechanism 14 is controlled by the control device 9 to raise and lower the squeegee 13 with respect to the paste tank 12 (arrow B shown in FIG. 1). Thereby, the distance (squeegee gap) between the paste film forming surface 12a and the lower edge of the squeegee 13 can be changed, and the thickness t (FIG. 1 and FIG. 1) of the paste film p formed on the paste film forming surface 12a. 3 (a)) can be changed.

  For the paste P, if the bump 2a is a solder bump, for example, a flux paste not containing solder particles is used, and if the bump 2a is a gold bump, for example, a solder paste is used. In this embodiment, as will be described later, the image of the paste P attached to the surface of the bump 2a is recognized via the camera 8, but the paste P is colored to facilitate the recognition of the paste P. Things are used.

  The component suction moving unit 7 includes a mounting head 16 including a plurality of suction nozzles 15 for sucking the component 2, a head moving guide 17 serving as a guide for moving the mounting head 16 in a horizontal plane, and the mounting head 16 as a head moving guide. 17 includes a head actuating mechanism 18 that moves along the nozzle 17 and a nozzle actuating mechanism 19 that causes each suction nozzle 15 to move up and down the mounting head 16 and suck the component 2. The head operating mechanism 18 is controlled by the control device 9 to move the mounting head 16 in the horizontal direction along the head moving guide 17 (arrow C shown in FIG. 1), and the nozzle operating mechanism 19 is controlled by the control device 9. Each suction nozzle 15 is moved up and down with respect to the mounting head 16 (arrow D shown in FIG. 1), and the component 2 is vacuum-sucked by each suction nozzle 15.

  The camera 8 is installed with the imaging surface facing upward, and images the component 2 picked up by the component suction moving unit 7 under the control of the control device 9 from below. The image data of the component 2 imaged by the camera 8 is sent to the image recognition unit 9a (FIG. 1) of the control device 9, and the image recognition unit 9a of the control device 9 recognizes the image of the component 2 based on the image data. .

  In FIG. 1, an input unit 21 and a display unit 22 are connected to the control device 9. The operator of the component mounting machine 3 can input various operation inputs to the control device 9 from the input unit 21, and the control device 9 provides various information such as characters and images to the operator via the display unit 22.

  Next, a component mounting procedure by the component mounter 3 will be described using the flowchart of FIG. The component mounting procedure shown here includes an execution procedure of the paste transfer method in one embodiment of the present invention.

In FIG. 2, first, the control device 9 operates the conveyor belt 10 to carry the board 1 sent from the upstream device into the component mounting machine 3 and position it at a predetermined reference position (step ST1). Then, an image recognition of a positioning mark (not shown) provided on the substrate 1 is performed by the substrate camera 16a (FIG. 1) attached to the mounting head 16 and the imaging surface is directed downward, and the substrate 1 is displaced from the reference position. Ask for. After positioning the substrate 1 at the reference position, the control device 9 operates the parts feeder 5 to supply the component 2 to a predetermined component supply position (step ST2).

  When the control device 9 causes the parts feeder 5 to supply the component 2 to the component supply position, the control device 9 moves the mounting head 16 above the component supply position and causes the suction nozzle 15 to pick up the component 2 (step ST3). The pickup of the component 2 is performed by lowering the suction nozzle 15 and bringing its lower end portion into contact with the upper surface of the component 2 and causing the suction nozzle 15 to vacuum-suck the component 2.

  When the controller 9 causes the suction nozzle 15 to pick up the component 2, the squeegee 13 is reciprocated relative to the paste tank 12 to form a paste film p having a constant thickness on the paste film forming surface 12 a ( Step ST4). At this time, the thickness of the paste film p is set in advance according to the size and shape of the bump 2a of the component 2 picked up by the suction nozzle 15 in step ST3. Note that this paste film formation process does not necessarily have to be performed after the pick-up process of the component 2 in step ST3, but may be performed before that.

  After forming the paste film p on the paste film forming surface 12a, the control device 9 controls the operation of the mounting head 16 and moves the component 2 currently picked up by the suction nozzle 15 above the paste film forming surface 12a. (FIG. 3A). Then, the component 2 is lowered (the suction nozzle 15) to bring the bump 2a into contact with the paste film p (FIG. 3B), and then the component 2 is pulled up (FIG. 3C). As a result, the paste P corresponding to the thickness t of the paste film p is transferred to the bumps 2a of the component 2 (step ST5).

  After transferring the paste P to the bumps 2a of the component 2, the control device 9 moves the mounting head 16 above the camera 8 and causes the camera 8 to pick up an image of the component 2 currently picked up by the suction nozzle 15 from below. Then, image recognition is performed from the image data of the component 2 obtained in this way, and the surface state of the bump 2a after the paste P is transferred is detected (step ST6).

  The surface state of the bump 2a is detected based on the position and spread state of the paste P in the image of the component 2 imaged by the camera 8. This is because the position and spread of the paste P in the image when the component 2 is viewed from below depends on the position and spread of the paste P transferred to the bump 2a on the surface of the bump 2a. It is. For example, when the paste P adheres to a part of the lower half of the bump 2a (FIG. 4A), when the component 2 is viewed from below, it is smaller than the bump 2a at the position where the bump 2a is provided. The paste P spreading in diameter can be recognized (FIG. 4B).

  When the control device 9 detects the surface state of the bump 2a after the paste P is transferred, the controller 9 determines whether the paste P is attached to the bump 2a based on the result (step ST7).

  For example, whether the paste P adheres to the bumps 2a is determined by whether or not the paste P adheres to the bumps 2a, and further, the paste P to which the adhered paste P adheres has a spread beyond a predetermined standard. Judgment by whether or not. For example, in the case where there is a reference that the paste P is in a good adhesion state even if a slight amount of the paste P adheres to the surface of the bump 2a, the adhesion state of the paste P shown in FIGS. 4 (a) and 4 (b) Is determined to be good.

  When it is determined in step ST7 that the state of adhesion of the paste P to the bump 2a is good, the control device 9 directly recognizes the component 2 by the camera 8 (step ST8). This recognition of the component 2 is to obtain a positional deviation of the component 2 with respect to the suction nozzle 15. The recognition for obtaining the positional deviation of the component 2 may be performed simultaneously in the image recognition process for detecting the surface state of the bump 2a in step ST6.

  When the recognition of the component 2 is completed, the control device 9 moves the mounting head 16 above the substrate 1 positioned in step ST1, and mounts the component 2 currently picked up on the target mounting position on the substrate 1 (step ST9). ). This target mounting position is determined for each component 2, and the data is stored in advance in the storage unit 9 b (FIG. 1) of the control device 9.

  Here, when the component 2 is mounted at the target mounting position on the substrate 1, the positional deviation of the substrate 1 from the reference position obtained in step ST1 and the positional deviation of the component 2 with respect to the suction nozzle 15 obtained in step ST8 are canceled. As described above, the position of the suction nozzle 15 is corrected.

  When the component 2 is mounted on the substrate 1, the component 2 is thermocompression bonded to the substrate 1. Thereby, when the bump 2a is a solder bump, a part of the solder bump is melted, and when the bump 2a is a gold bump, the solder paste applied (attached) to the bump 2a is melted. The electrodes are soldered together.

  When the mounting of the component 2 on the board 1 is completed, the control device 9 proceeds to the next step ST10.

  When the control device 9 determines in step ST7 that the state of adhesion of the paste P to the bump 2a is defective (transfer failure), the control device 9 retransfers the paste P to the bump 2a. In the retransfer of the paste P, the control device 9 first determines whether or not the number of retransfers executed so far for the component 2 currently picked up is equal to or less than a predetermined number of times (step ST11). This specified number of times gives a limit to the number of executions of retransfer of the paste P performed when the state of adhesion of the paste P to the bumps 2a is poor. When limiting the number of executions of retransfer to "3" The specified number of times is set to “3”.

  If the result of determination in step ST11 is that the number of retransfers performed so far on the currently picked-up component 2 is less than or equal to the specified number, the control device 9 performs the elevation control of the squeegee 13 and pastes The thickness t of the paste film p on the paste film forming surface 12a is changed in accordance with the P component and the number of times the paste P is transferred to the component 2 currently picked up (step ST12). Specifically, when the paste P contains solder particles as in the case of the solder paste, the number of executions of the paste transfer (the total number of executions of the first transfer and the subsequent retransfer) increases. The thickness t of the paste film p is reduced, and when the paste P does not contain solder particles, the thickness t of the paste film p is not reduced even if the number of executions of the transfer of the paste P increases.

  This is because when the paste P is a solder paste and the component contains solder particles, the paste P is retransferred so that the paste P enters between the adjacent bumps 2a and the bump 2a. This is because they are connected by a paste P containing solder (FIG. 5), and when the component 2 is bonded to the substrate 1, a bridge may be formed between adjacent electrodes. On the other hand, if the paste P is a flux paste that does not contain solder particles and the component does not contain solder particles, the component 2 can be removed even if the paste P enters between adjacent bumps 2a. While there is little risk of a bridge being formed between adjacent electrodes when mounted on the substrate 1, if the paste P is insufficient, an open defect may occur due to insufficient wettability when the component 2 is bonded to the substrate 1. Because there is.

  When the thickness t of the paste film p is changed in step ST12, the control device 9 returns to step ST5 and controls the operation of the component suction moving unit 7 to bring the bump 2a of the component 2 into contact with the paste film p, thereby causing the bump 2a The paste P is transferred again. Then, the surface state of the bump 2a after the paste P is re-transferred is detected (step ST6), and whether or not the paste P is attached to the bump 2a is determined (step ST7). As a result, if the adhesion state of the paste P to the bump 2a is good, the process proceeds to step ST8 to mount the component 2 on the substrate 1, and the adhesion state of the paste P to the bump 2a is poor (transfer failure). ), The process proceeds again to step ST11, and retransfer of the paste P is performed again.

  As a result of repeating the retransfer of the paste P as described above, when the number of retransfers executed so far exceeds the specified number in the determination of step ST11, the control device 9 determines the thickness of the paste film p. Without changing the length t, an error is notified to the operator via the display unit 22 (step ST13), and the component 2 currently picked up by the suction nozzle 15 by moving the mounting head 16 is moved to a predetermined component disposal position. (Step ST14), the process proceeds to step ST10.

  In step ST10, the control device 9 determines whether or not the mounting of all the components 2 to be mounted on the substrate 1 to the substrate 1 has been completed. As a result, when the mounting of all the components 2 on the substrate 1 has not been completed, the process returns to step ST2, and mounting of the components 2 that are not yet mounted on the substrate 1 is performed. On the other hand, when all the components 2 have been mounted on the substrate 1, the conveyor belt 10 is operated to carry the substrate 1 out of the component mounter 3 (step ST15).

  As described above, the paste transfer device (component mounting machine 3) according to the present embodiment transfers the paste P onto the bump 2a by bringing the bump 2a of the component 2 into contact with the paste film p formed to have a constant thickness. There is a surface state detection unit (image recognition unit 9a of the camera 8 and control device 9) for detecting the surface state of the bump 2a after the paste P is transferred, and the surface of the bump 2a detected by the surface state detection unit Based on the state, a determination unit (control device 9) that determines whether or not the paste P is attached to the bump 2a, and the determination unit determines that the paste P is attached to the bump 2a is defective (transfer failure). In this case, the paste film thickness changing unit (the paste film forming unit 6 and the control unit) changes the thickness t of the paste film p in accordance with the component of the paste P or the number of executions of the transfer of the paste P to the component 2. Apparatus 9) and a retransfer execution unit (component suction moving unit 7) for bringing the bump 2a of the component 2 into contact with the paste film p whose thickness t has been changed by the paste film thickness changing unit and transferring the paste P to the bump 2a again. And a control device 9).

  In the paste transfer method according to the present embodiment, the bump 2a of the component 2 is brought into contact with the paste film p formed to have a constant thickness so that the paste P is transferred to the bump 2a. Based on the surface state detection step (step ST6) for detecting the surface state of the subsequent bump 2a and the surface state of the bump 2a detected in the surface state detection step, the quality determination of the state of adhesion of the paste P to the bump 2a is made. A determination process (step ST7), and when it is determined in the determination process that the adhesion state of the paste P to the bump 2a is defective (transfer defect), the component of the paste P or the transfer of the paste P to the component 2 is determined. A paste film thickness changing step (step ST12) in which the thickness t of the paste film p is changed according to the number of executions, and the thickness t being changed in the paste film thickness changing step. Contacting the bumps 2a of the component 2 in the strike layer p contains retransfer step (step ST5) to retransfer the paste P in the bump 2a.

As described above, in the paste transfer device (component mounting machine 3) and the paste transfer method according to the present embodiment, the bump 2a of the component 2 is brought into contact with the paste film p formed to have a constant thickness, and the paste P is applied to the bump 2a. After the surface is transferred, the surface state of the bump 2a is detected, and the bump 2a
As a result of determining whether or not the paste P is attached to the bump 2a, if the adhesion state of the paste P to the bump 2a is determined to be defective (transfer failure), the bump 2a of the component 2 is again applied to the paste film p. The paste P is transferred (re-transferred) to the bumps 2a by contacting them.

  As described above, in the paste transfer device (component mounting machine 3) and the paste transfer method according to the present embodiment, the component 2 in which the transfer failure of the paste P has occurred is not discarded, but the paste P is retransferred to the bumps 2a. Therefore, the yield is improved because it is converted into a non-defective product as much as possible.

  At the time of retransfer of the paste P, the thickness t of the paste film p is changed according to the number of executions of the transfer of the paste P to the component of the paste P or its component 2, and the paste P is retransferred. Adverse effects that may occur, that is, excessive paste P adheres to the bumps 2a due to retransfer of the paste P, and when the component 2 is bonded to the substrate 1, the bumps 2a or between the electrodes of the substrate 1 It is possible to prevent as much as possible the inconvenience that a bridge is formed and a short circuit occurs.

  Although the embodiments of the present invention have been described so far, the present invention is not limited to those shown in the above-described embodiments. For example, in the above-described embodiment, the detection of the surface state of the bump 2 a is performed by imaging the lower surface of the component 2 picked up by the component suction moving unit 7 from below with the camera 8. Depending on whether or not the lower edge of each bump 2a is irradiated with inspection light such as laser or infrared from the side of the bump 2a and reflected (if the paste adheres to the bump 2a, the inspection light is blocked) The surface state 2a (whether or not the paste P is attached) may be detected.

  In the above-described embodiment, a colored paste is used for the paste P. However, as described above, this is transferred to the bump 2a when the image of the component 2 is recognized via the camera 8. The paste P is not necessarily colored because it is for facilitating recognition of the paste P. In the above-described embodiment, the thickness of the paste film is changed in accordance with both the paste component and the number of times the paste is transferred. The thickness of the paste film may be changed according to the above. Accordingly, for example, the present invention includes a configuration in which the thickness of the paste film is always reduced as the number of times the paste is transferred is increased regardless of the components of the paste.

  Provided are a paste transfer device and a paste transfer method capable of converting a part in which a paste transfer failure has occurred into a non-defective product as much as possible and improving yield.

The block diagram of the component mounting machine containing the paste transcription | transfer apparatus in one embodiment of this invention The flowchart which shows the mounting procedure to the board | substrate of the components including the execution procedure of the paste transfer method in one embodiment of this invention (A) (b) (c) Explanatory drawing of the procedure which transcribe | transfers paste to the bump in one embodiment of this invention (A) Side view (b) Bottom view of a part showing the state of adhesion of paste to bumps in an embodiment of the present invention The side view of the component which shows the adhesion state to the bump of paste in one embodiment of this invention

Explanation of symbols

2 Component 2a Bump 3 Component mounting machine (Paste transfer device)
6 Paste film forming part (Paste film thickness changing part)
7 Parts suction moving part (re-transfer execution part)
8 Camera (Surface condition detector)
9 Control device (re-transfer execution unit, determination unit, paste film thickness changing unit)
9a Image recognition unit (surface state detection unit)
P paste p paste film t thickness of paste film

Claims (6)

  A paste transfer device for transferring a paste to a bump by bringing a component bump into contact with a paste film formed to a constant thickness, and a surface state detection unit for detecting a surface state of the bump after the paste is transferred Based on the surface state of the bump detected by the surface state detection unit, a determination unit that determines whether the paste is attached to the bump is good, and the determination unit determines that the paste is attached to the bump is bad. The paste film thickness changing unit changes the thickness of the paste film according to the paste component or the number of times the paste is transferred to the component, and the paste film has a thickness changed by the paste film thickness changing unit. A paste transfer device comprising: a re-transfer executing unit that makes the bump contact and re-transfers the paste to the bump.   2. The paste transfer device according to claim 1, wherein the paste film thickness changing unit reduces the thickness of the paste film as the number of times of transfer of the paste increases when the paste contains solder particles.   The paste transfer apparatus according to claim 1, wherein a colored paste is used.   A paste transfer method for transferring a paste to a bump by bringing a component bump into contact with a paste film formed to a certain thickness, and detecting a surface state of the bump after the paste is transferred; Based on the surface state of the bump detected in the surface state detection step, a determination step for determining whether the paste is attached to the bump is good, and in the determination step, the state of the paste attached to the bump is determined to be defective. The paste film thickness changing process changes the paste film thickness according to the paste component or the number of times the paste is transferred to that part, and the paste film thickness is changed in the paste film thickness changing process. And a re-transfer executing step of re-transferring the paste to the bumps by bringing the bumps into contact with each other.   5. The paste transfer method according to claim 4, wherein, in the paste film thickness changing step, when the paste contains solder particles, the paste film thickness is reduced as the number of times the paste is transferred is increased.   6. The paste transfer method according to claim 4, wherein a colored paste is used.

Images