JP4360193B2 - Paste transfer method to electronic parts - Google Patents

Description

  The present invention relates to a method and an apparatus for applying a paste such as a conductive paste or a flux to an electronic component, and more particularly to a method and an apparatus for applying a paste to an electronic component by a transfer method on a transfer stage.

  Conventionally, a method of applying a conductive paste to an electronic component by a transfer method is known. When applying the conductive paste by the transfer method, it is desirable to transfer the conductive paste to a uniform thickness.

  FIGS. 9A to 9E are partial cutaway cross-sectional views for explaining the conductive paste transfer method described in Patent Document 1 below. In this transfer method, as shown in FIG. 9A, the suction head 52 is disposed above the transfer stage 51. The suction head 52 is configured to be movable in the vertical direction. The electronic component 53 is held by suction on the lower surface of the suction head 52. Bumps 54 and 55 are formed on the lower surface of the electronic component 53. Here, a conductive paste is applied to the surfaces of the bumps 54 and 55 by a transfer method.

  In the method described in Patent Document 1, first, the electronic component 53 is sucked and held by the suction head 52. Next, the suction head 52 is lowered. When the suction head 52 reaches a predetermined height position, the descending speed is reduced. Then, when the bumps 54 and 55 are pressed against the upper surface of the transfer stage 51 as shown in FIG. 9B, the pressing load is detected. When the pressing load reaches a predetermined value, it is determined that the flattening is completed, and the lowering of the suction head 52 is stopped. The height of the suction head 52 at this time is stored in advance.

  Next, as shown in FIG. 9C, after the flattening, the suction head 52 is moved upward. In this case, the lower ends of the bumps 54 and 55 are flattened by flattening.

  Thereafter, as shown in FIG. 9D, the conductive paste 57 is spread by moving the squeegee 56 in the horizontal direction on the transfer stage 51. Thereby, as shown in FIG. 9E, the conductive paste layer 57A is formed to have a predetermined film thickness.

The electronic component held by the suction head 52 is lowered on the conductive paste layer 57A, the conductive paste is attached to the bumps 54, 55, and then the suction head 52 is raised. In this case, the height position of the suction head at the time of transfer of the conductive paste is obtained based on the previously stored height position of the suction head 52, and the suction head 52 is lowered to the height position at the time of transfer. Transcription is performed.
JP 2001-267728 A

  As described above, in the conductive paste transfer method described in Patent Document 1, the bumps 54 and 55 are flattened, and the suction head 52 at the time of transfer is based on the height position of the suction head 52 when the flattening is completed. The height position of is determined. By controlling the height position of the suction head 52 during transfer and the thickness of the conductive paste layer 57A thus determined, the conductive paste is transferred to the surfaces of the bumps 54 and 55 with a uniform thickness.

  However, unlike a conductive paste, for example, when transferring a low-viscosity paste such as a flux applied to an electrode or the like before soldering by a transfer method, the method described in Patent Document 1 applies a flux with high accuracy. I couldn't. That is, even if the squeegee 56 is moved in the horizontal direction on the upper surface of the transfer stage 51 to spread the flux, the viscosity of the flux is low, so that the thickness is uniform as in the conductive paste layer 57A shown in FIG. A flux layer cannot be formed. Further, even when a uniform thickness flux layer is formed by the squeegee 56, the viscosity is low, and the flux immediately spreads to the outside, and the thickness of the flux layer has to be reduced.

  On the other hand, when a paste such as a flux is transferred to a large number of electronic components, the transfer stage may be replaced. As long as the position is not obtained, the stop position of the suction head fluctuates, which causes a problem that the amount of paste transfer varies.

  Moreover, in the transfer method of the electrically conductive paste described in Patent Document 1, the application method by transferring the electrically conductive paste to the bumps 54 and 55 shown in FIG. 9 is shown. The same problem occurs when a low-viscosity paste such as flux is applied to a part, for example, a flat electrode or a metal case constituting an electronic component.

The object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to transfer a paste with high accuracy and a uniform film thickness even when a paste having a low viscosity is applied to an electronic component by a transfer method. and to provide a paste transfer how to electronic components possible.

According to a first aspect of the present invention, there is provided a step of supplying a paste into the recess of a transfer stage provided with a recess on the upper surface, and a squeegee is moved on the upper surface of the transfer stage to fill the recess with the paste. Scraping the paste outside the recess, dipping a part of the electronic component in the paste inside the recess of the transfer stage, transferring the paste to a part of the electronic component, and lifting the electronic component from the recess A paste transfer method to an electronic component comprising a step , wherein a groove having a depth relatively deeper than that of the remaining portion is formed in the recess, and the electronic component is transferred to the paste. The protrusion has a protrusion, the recess has a shape corresponding to a part of the electronic component, and the protrusion enters the groove, and the surface of the remaining portion in the recess in the transfer step An electronic component method paste transfer, wherein said part of the electronic components are in contact.

  In another specific aspect of the paste transfer method to the electronic component according to the present invention, a plurality of types of grooves having different depths are provided as the grooves.

  In still another specific aspect of the method for transferring a paste to an electronic component according to the present invention, a flux that is applied before joining with solder is used as the paste.

  In the paste transfer method to the electronic component according to the present invention, the paste is supplied into the concave portion provided on the upper surface of the transfer stage, and the paste is filled in the concave portion by moving the squeegee, and the paste outside the concave portion. Is scraped off, a part of the electronic component is immersed in the paste in the recess, and the paste is transferred to a part of the electronic component. Therefore, for example, even when a paste having a low viscosity such as flux is used, the paste is reliably held in the recess. Therefore, by controlling the depth of the recess, the paste can be transferred to the outer surface of the electronic component with a uniform thickness and with high accuracy.

In the paste transfer method to the electronic component according to the present invention, since is formed deep grooves than partially relatively remainder of the depth in the recess, for example a portion protrudes below the electronic component If it is required to apply the paste to the protruding portion, the paste can be applied to a uniform thickness according to the present invention. In particular, when it is necessary to apply a paste such as a flux to a metal case having a downward projecting part as a part of an electronic component, the paste is reliably and easily applied to the downward projecting part of the metal case according to the present invention. Can be applied.

  When a plurality of types of grooves having different depths are provided as the grooves, the paste is uniformly and reliably provided in accordance with the present invention for electronic components having a plurality of downward protruding portions having different protruding lengths. Can be applied.

  When the paste is a flux used before soldering, even if the flux has a low viscosity, the flux can be uniformly transferred to the outer surface of the electronic component according to the present invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention.

  1A and 1B are schematic front cross-sectional views for explaining a paste transfer method for an electronic component according to an embodiment of the present invention.

  In this embodiment, a paste transfer apparatus having a transfer stage 1 and a squeegee 2 is used. A recess 1 b is formed on the upper surface 1 a of the transfer stage 1. In the present embodiment, the recess 1b is configured to have a predetermined depth, but a groove 1c deeper than the remaining portion is formed in the recess 1b.

  The lower end 2 a of the squeegee 2 is in contact with the upper surface 1 a of the transfer stage 1. The squeegee 2 is configured such that it can be moved in the direction of the arrow with the lower end 2 a in contact with the upper surface 1 a of the transfer stage 1.

  When transferring the paste, the paste 3 is supplied to the upper surface of the transfer stage 1, and the squeegee 2 is moved in the direction of the arrow, that is, in the horizontal direction, so that the paste 3 is filled in the recess 1b. Further, excess paste 3 is scraped off by the squeegee 2.

  In this embodiment, a low-viscosity flux that is applied to the electronic component before soldering is used as the paste 3. Even if such a flux is applied so as to have a predetermined film thickness on a flat surface, it immediately spreads outward from the outer edge portion. Therefore, it is difficult to form a flux layer having a desired thickness.

  In the present embodiment, the paste 3 is transferred to the electronic component 4 in FIG. 1 using the transfer stage 1 and the squeegee 2. Although the electronic component 4 is schematically shown in FIG. 1, the paste 3 is applied to the metal case of the electronic component 4 here. The metal case of the electronic component 4 has a joint 4a to which the paste is transferred below. In the present embodiment, the joint portion 4a hangs downward from the other portions, and a projecting portion 4b projecting downward is formed at the center of the joint portion 4a.

  The depth Y from the recess 1b on the transfer stage 1 side to the bottom of the groove 1c is made larger than the downward protrusion amount X from the lower end of the joint 4a of the protrusion 4b.

  On the other hand, the electronic component 4 is held by a holding member 5 shown schematically. The holding member 5 is movable in the vertical direction by the electronic component driving device 6. Therefore, the electronic component 4 can be moved in the vertical direction together with the holding member 5. When the paste is transferred, the electronic component 4 is moved downward, and the joint 4a is inserted into the recess 1b as shown in FIG. 1 (b). In this case, the protrusion 4b fits into the groove 1c. Therefore, next, by pulling up the electronic component 4, the paste 3 is transferred to the outer surface of the joint 4 a and the outer surface of the protruding portion 4 b of the electronic component 4. In this case, since the paste 3 is filled in the recess 1b, even if the viscosity of the paste 3 is low, the paste 3 is in the recess 1b so as to have a shape according to the planar shape of the recess 1b. Filled. Moreover, a paste having a thickness corresponding to the depth of the recess 1b is reliably formed. Also in the groove 1c, the paste is filled so as to have a thickness corresponding to the depth of the groove 1c.

  Therefore, according to the present embodiment, the paste can be reliably transferred to the lower surface of the joint portion 4a and the lower surface of the protruding portion 4b so as to have a uniform thickness. In other words, even when the viscosity of the paste 3 is low, by controlling the depth of the recess 1b and the depth direction dimension from the bottom of the recess 1b of the groove 1c, the joint 4a of the electronic component 4 and The paste can be reliably transferred to the lower surface of the protrusion 4b so as to have a desired thickness.

  1A and 1B, the shape of the electronic component 4 and the joint portion 4a of the metal case of the electronic component 4 are schematically illustrated. More specifically, the electronic components illustrated in FIGS. The paste transfer method of the present invention can be provided for the component 11 or the like. In the electronic component 11 shown in FIGS. 2 and 3, a plurality of electronic component elements such as an IC 13 and a multilayer ceramic capacitor 14 are mounted on the case substrate 12. The IC 13 has a plurality of bumps 15 on the lower surface. The bumps 15 are joined to the electrode lands 15a on the case substrate 12 by soldering.

  Prior to joining the bumps 15 of the IC 13 by soldering, it is necessary to apply a flux to the surface of the bumps 15. The paste transfer method shown in FIGS. 1A and 1B can be used for such flux application. That is, if a concave portion corresponding to the bump 15 is formed as the concave portion 1b shown in FIGS. 1A and 1B, the flux is reliably transferred onto each bump 15 according to the above-described embodiment. be able to.

  Further, a portion where a plurality of electronic components such as the IC 13 and the multilayer ceramic capacitor 14 are mounted is covered with a metal case 16. The metal case 16 has joints 16a to 16c and the like. The joining portions 16a to 16c are joined to the electrode lands 15b to 15d on the substrate 12 by solder. As is apparent from FIG. 2, the tip portions of the joint portions 16a to 16c protrude downward from the other metal case portions. Therefore, the application of the flux to the lower surfaces of the joint portions 16a to 16c can be performed according to the embodiment shown in FIGS. 1 (a) and 1 (b). That is, by forming a concave portion having a shape corresponding to the joint portions 16a to 16c as the concave portion 1b, the flux can be reliably transferred to the lower surface of the joint portions 16a to 16c with a uniform thickness.

  4 to 6 are diagrams illustrating an example of the transfer stage 1 described above. In the transfer stage 21 shown in a schematic plan view in FIG. 4, a plurality of recesses 22 and a plurality of recesses 23 are formed. The recesses 22 and 23 are both filled with paste, but are provided to transfer the paste to different electronic components.

  FIG. 5 is an enlarged plan view showing the recess 22, and FIG. 6 is an enlarged sectional view taken along the line ZZ in FIG. 5.

  As is apparent from FIGS. 5 and 6, the groove 22 a is formed in the recess 22 so as to have a depth different from that of the other portions of the recess 22. As shown in FIG. 5, a groove 22b is also formed, and the groove 22b is deeper than the groove 22a. Thus, the recess in the transfer stage 21 used in the present invention may have a plurality of grooves having different depths. That is, a plurality of grooves having different depths may be provided in one recess depending on the shape of the protruding portion on the electronic component side to which the paste is transferred.

  FIGS. 7A to 7C are cross-sectional views for explaining a process of applying a paste to the above-described IC 13 according to the present invention.

  In the embodiment shown in FIGS. 7A to 7C, the IC 13 is held by the suction head 31. A plurality of bumps 15 are formed on the lower surface of the IC 13 as schematically shown.

  As shown in FIG. 7A, a recess 32 a is formed on the upper surface of the transfer stage 32. Then, the paste 33 is filled in the recess 32a. Filling the recess 32 a with the paste 33 is performed by moving the lower end 34 a of the squeegee 34 in a state where the lower end 34 a is in contact with the upper surface of the transfer stage 32. At the same time that the recess 23 a is filled with the paste 23, excess paste 33 is scraped off by the squeegee 34.

  Thereafter, the suction head 31 is lowered to immerse the bump 15 in the paste 33 in the recess 32a. Thereafter, as shown in FIG. 7C, the IC 33 held by the suction head 31 is pulled up, whereby the paste 33 is transferred to the lower surface of the bump 15 with a uniform thickness.

  Thus, the paste transfer method according to the present invention is used to transfer paste such as flux to various electronic parts such as the metal case 16 and the IC 13 shown in FIG. Therefore, in this specification, the electronic component widely includes components that are electronic component constituent members, and the above-described metal case 16 and the like are also included in the electronic component.

  As shown in FIG. 7, the flux was transferred to the bump surface according to the present invention, and then the IC 13 was bonded onto the substrate by soldering. In this case, the flux was transferred in the same manner to the ICs of a plurality of types of lots, and the bumps of the IC were joined to the electrode lands on the substrate by soldering. If the amount of flux transferred varies, the size of the gap between the IC and the substrate changes. This is because the amount of solder wetting and spreading after melting the solder varies depending on the amount of flux applied.

  Therefore, the flux was transferred to a plurality of types of ICs according to the above embodiment and bonded onto the substrate by soldering, and then the VCO voltage was measured as the IC characteristics. For comparison, a flux layer is formed according to a conventional method, that is, using a squeegee so as to have a predetermined thickness on the upper surface of the transfer stage, and then the IC is immersed in the flux layer and then pulled up. Was transcribed. The IC to which the flux was transferred according to this conventional method was also joined to the substrate by soldering in the same manner as in the above example. And the VCO voltage of IC in the obtained structure was measured. Also in the conventional example, the above-described measurement was performed for two types of ICs.

  The results are shown in FIG.

  A1 and A2 in FIG. 8 show variations in VCO voltage (V) measured for ICs of two types of lots in the conventional method. Further, B1 to B6 on the horizontal axis in FIG. 8 indicate variations in VCO voltage (V) in the ICs of the six types of lots B1 to B6 when the flux is applied according to the transfer method of the above embodiment.

  As is apparent from FIG. 8, it can be seen that according to the above embodiment, the variation in the VCO voltage (V) between lots and the variation in lots can be remarkably reduced as compared with the conventional method.

(A), (b) is schematic sectional drawing for demonstrating the paste transfer method to the electronic component which concerns on one Embodiment of this invention. The perspective view which shows an example of the electronic component used for the paste transcription | transfer method of embodiment of FIG. FIG. 3 is a front sectional view of the electronic component shown in FIG. 2. The top view for demonstrating the transcription | transfer stage used by other embodiment of this invention. FIG. 5 is an enlarged plan view showing one concave portion of the transfer stage shown in FIG. 4. Sectional drawing which follows the ZZ line | wire of FIG. (A)-(c) is each front sectional drawing for demonstrating the process of transferring a flux to the bump of IC in other embodiment of this invention. In the embodiment shown in FIG. 7, after the flux is transferred, the IC VCO voltage in the structure in which the IC is laminated on the substrate, and the flux is transferred according to the conventional method for comparison. The figure which shows the dispersion | variation between lots of VCO voltage of IC of the structure obtained similarly. (A)-(e) is each partial notch sectional drawing for demonstrating an example of the paste transfer method to the conventional electronic component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transfer stage 1a ... Upper surface 1b ... Concave 1c ... Groove 2 ... Squeegee 2a ... Lower end 3 ... Paste 4 ... Electronic component 4a ... Joint part 4b ... Protrusion part 11 ... Electronic component 12 ... Substrate 12a-12d ... Electrode land 13 ... IC
DESCRIPTION OF SYMBOLS 14 ... Multilayer ceramic capacitor 15 ... Bump 16 ... Metal case 16a-16c ... Joint part 21 ... Transfer stage 22, 23 ... Recess 22a ... Groove 22b ... Groove 31 ... Adsorption head 32 ... Transfer stage 32a ... Recess 33 ... Paste 34 ... Squeegee 34a ... lower end

Claims (3)

Supplying a paste into the recess of the transfer stage provided with a recess on the upper surface;
On the upper surface of the transfer stage, a step of moving the squeegee to fill the recess with the paste and scraping the paste outside the recess;
Immersing a part of the electronic component in the paste in the recess of the transfer stage, and transferring the paste to a part of the electronic component;
A method of transferring the electronic component to the electronic component, wherein a groove having a deeper depth than the remaining portion is formed in the recess. A part of the electronic component to which the toner is transferred has a protruding portion, and the concave portion has a shape corresponding to a part of the electronic component, and the protruding portion enters the groove. A part of the electronic component contacts the surface of the remaining portion of the electronic component paste transfer method.   The paste transfer method to the electronic component according to claim 1, wherein a plurality of types of grooves having different depths are provided as the grooves.   The paste transfer method to an electronic component according to claim 1, wherein the paste is a flux applied before joining with solder.

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