JP5083259B2 - Conductive material filling apparatus and filling method using the same - Google Patents

Description

  The present invention relates to a filling device that fills a via hole provided on the surface of a sheet material with a conductive material that melts at a temperature higher than room temperature, and a filling method using the same.

  There is a method for manufacturing a multilayer circuit board in which a plurality of resin films on which a conductor pattern is formed are stacked and bonded together by heating and pressing. In the multilayer circuit board manufacturing method, generally, via holes formed in the resin film are filled with a conductive paste obtained by refining a metal filler with a solvent to form a paste, and the metal filler is sintered to form a conductor pattern. Ensure electrical continuity between. In the production of the multilayer circuit board, in order to reduce the production cost, a sheet material having a large area capable of taking a large number of 450 mm squares, for example, is used as the resin film. In the sheet material of this size, generally, 3 to 50,000 via holes are formed.

  A fluid material filling device and a filling method for filling a fluid material such as a conductive paste in via holes provided on the surface of the sheet material are disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-182023 (Patent Document 1) and It is disclosed in Japanese Patent Laying-Open No. 2005-329570 (Patent Document 2).

  FIG. 6A is a schematic cross-sectional view showing a state of forming a bottomed via (via hole having a conductor pattern as a bottom) H on the surface of the sheet material 10, and FIG. It is sectional drawing which shows the mode of the filling of the conductive paste 4 to the via | veer H. In addition, the sheet material 10 shown in FIG. 6 has a metal (copper) foil 2 bonded to one surface of a resin film 1 made of a thermoplastic resin, and a protective film 3 bonded to the opposite surface. . The copper foil 2 is actually processed into a predetermined conductor pattern, but is simplified in FIG.

  As shown in FIG. 6A, in the via hole forming step, a laser beam from the laser processing apparatus L is applied to the sheet material 10 from above the protective film 3, and the bottomed via H with the copper foil 2 as the bottom is formed. Form. The bottomed via H is a fine hole having a diameter of 100 to 150 μm and a depth of 50 to 250 μm, for example.

  Next, in the paste filling step shown in FIG. 6 (b), the conductive paste 4 supplied to the surface of the sheet material 10 is mechanically squeegeeed (squeezed) S, and the bottom via H Push in to fill. The conductive paste 4 is dispersed in a volatile solvent such as terpineol in order to use a fine powder of several μm of silver (Ag) and tin (Sn) as a metal filler and keep the ratio of silver and tin stable. It is a paste. In filling the conductive paste 4, vacuum filling is performed because it is necessary to completely replace the air in the bottomed via H with the conductive paste 4. More specifically, the conductive paste 4 is held in the filling head of the filling device, and the opening of the filling head is pressed against the surface of the sheet material 10 to constitute a filling chamber that can be evacuated. Then, using the squeegee S disposed in the filling chamber, the conductive paste 4 supplied to the surface of the sheet material 10 is pushed through the protective film 3 and filled into the bottom via H. The protective film 3 is for preventing the conductive paste 4 from adhering to the surface of the resin film other than the bottomed via H, and is peeled off from the resin film 1 after the solvent of the conductive paste 4 is evaporated.

JP 2003-182023 A JP 2005-329570 A

  The conductive paste 4 shown in FIG. 6B is a non-Newtonian fluid composed of a silver or tin metal powder and a high-viscosity solvent such as terpineol or the like. To separate. For this reason, it is necessary to stir the conductive paste 4 even outside the filling operation time. Moreover, in order to ensure a high-quality filling rate, removal of bubbles in the conductive paste 4 is an essential matter. For this reason, after mixing a large amount of the conductive paste 4 in the air, a long period of high vacuum defoaming is required. However, when the conductive paste 4 is exposed to a vacuum for a long time, the solvent content in the conductive paste 4 evaporates, and the viscosity increases to change the filling composition. Therefore, in order to suppress an increase in viscosity in the conductive paste 4, the filling apparatus manages the vacuum pressure in the filling chamber at a vacuum pressure lower than the solvent vapor pressure of the conductive paste 4, and exhausts high vacuum before and after the filling chamber. It is filled with a room.

  In addition, for example, when filling 30,000 to 50,000 bottomed vias H in the 450 mm square sheet material 10 described above, the amount of the conductive paste 4 required is less than 5 g. However, in order to stabilize the composition of the conductive paste 4, about 2 kg of the conductive paste 4 is held and managed in the filling chamber of the filling device. Furthermore, since the non-flowing conductive paste 4 near the squeegee S adheres to the squeegee S due to the dilatancy phenomenon, the squeegee S needs to be regularly cleaned. When cleaning the squeegee S, the remaining conductive paste 4 is taken out from the filling head and the work is performed, so that the conductive paste 4 is wasted.

  As described above, handling of the conductive paste 4 requires careful attention, and maintenance and management requires a large number of man-hours and devices, and resource utilization efficiency is poor. In order to solve these problems of the conductive paste 4, the connection conductor between the wiring layers in the multilayer circuit board is easier to handle at the time of manufacture than the conventional conductive paste 4, and can improve the connection reliability and the manufacturing yield. A new conductive material and a filling method thereof have been invented. The conductive material is composed of a mixture of a metal filler and a low melting point solid dispersant that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature, and is in a solid state at room temperature. The conductive material is supplied onto the heated resin film, the softened conductive material is pushed into the bottom via and filled, and the filled resin film is cooled to room temperature to return the conductive material to a solid state. . About this electrically conductive material and its filling method, a patent application is currently pending (Japanese Patent Application No. 2008-296074).

  Accordingly, the present invention is a filling apparatus for filling a via hole provided on the surface of a sheet material with a conductive material that melts at a temperature higher than room temperature, and a filling method using the same. Compared to the conventional conductive paste filling device and the filling method using the same, the handling and maintenance of the conductive material is easy, the filling device is miniaturized and the utilization efficiency of the conductive material is increased. An object of the present invention is to provide a filling apparatus and a filling method using the same.

  The invention according to claim 1 is a conductive material filling device for filling a via hole provided in a surface of a sheet material with a conductive material that melts at a predetermined temperature higher than room temperature, in order to hold the sheet material A work holding mechanism section comprising: a filling base; a work heating heater capable of heating the conductive material supplied to the surface of the sheet material held by the filling base to a temperature equal to or higher than the predetermined temperature; and A filling head for supplying the conductive material to the surface of the sheet material held on the filling base and filling the via hole, and a filling head for moving the filling head in a horizontal direction and a vertical direction with respect to the surface of the sheet material An end surface of a filling squeegee that contacts the surface of the sheet material and rubs the conductive material supplied to the surface of the sheet material into the via hole. The conductive material in a solid state at room temperature is held in the interior of the sheet material, and the solid state conductive material is perpendicular to the surface of the sheet material. It is characterized by having a filling squeegee holder provided with a pusher that moves to the center.

  The filling device is a filling device that fills a via hole provided on the surface of a sheet material with a conductive material that melts at a predetermined temperature higher than room temperature. In other words, the filling device heats the conductive material in a solid state at room temperature to the predetermined temperature or more to melt the conductive material, and then fills the via hole provided on the surface of the sheet material. Therefore, in the filling apparatus, the work holding mechanism is provided with a work heater, and the conductive material supplied to the surface is heated by heating the sheet material held on the filling base by the work heater. Is trying to melt. The conductive material is sticked in a solid state at room temperature (hereinafter referred to as a stick conductive material) and is held in a filling squeegee holder of a filling head. The stick conductive material is applied to the surface of the sheet material by a pusher. Pressed. As a result, the tip portion is melted by heat conduction from the surface of the sheet material, and the melted conductive material is supplied to the surface of the sheet material. The molten conductive material supplied to the surface of the sheet material is rubbed into the via hole with a filling squeegee while the filling head is moved in the horizontal direction with respect to the surface of the sheet material by the filling head feed mechanism. As a result, the conductive material is filled in via holes provided on the surface of the sheet material.

  The above filling device makes it possible to use a conductive material that melts at a temperature higher than room temperature (in other words, a conductive material that is in a solid state at room temperature). Can be eliminated. That is, since the stick conductive material held in the filling squeegee holder of the filling device is in a solid state, unlike the conventional conductive paste, there is no need for vacuum defoaming or stirring in the filling squeegee holder, and a stable composition. Can be maintained over a long period of time. Moreover, since vacuum defoaming and stirring are not required, the filling head can be reduced in size.

  The amount of the stick conductive material held in the filling squeegee holder can be set to an arbitrary volume corresponding to the filling amount, and a plurality of sheet materials can be continuously filled. In addition, when filling the sheet material, the amount of molten conductive material supplied to the surface of the sheet material is limited to the minimum required amount by appropriately controlling the pressure applied to the sheet material of the stick conductive material by the pusher. can do. For example, when filling 50,000 to 50,000 bottomed vias (via holes with a conductor pattern at the bottom) in a 450 mm square sheet material, the amount of molten conductive material supplied to the surface of the sheet material is about 5 g. Can be limited to. This corresponds to about 1/40 of the amount of conventional conductive paste used.

  In the filling squeegee holder of the filling head, which is separated from the surface of the sheet material after filling, the conductive material at the melted tip portion returns to the solid state again, so that the filling squeegee can be easily cleaned in accordance with the next cycle. It is possible. Moreover, useless consumption of the conductive material accompanying this cleaning does not occur.

  Furthermore, in the conductive material filling apparatus, the filling head is moved to an arbitrary position on the sheet material and filled by using the above-described downsizing of the filling head and a conductive material in a solid state at room temperature. Is possible. In a conventional filling head that uses a conductive paste that can flow at room temperature, the surface of the sheet material functions as a bottom plate that holds the conductive paste in the filling head. It was necessary to move to slide. However, in the conductive material filling apparatus, when the filling head is away from the surface of the sheet material, the conductive material held in the filling squeegee holder is in a solidified state. Therefore, even if the filling head is separated from the surface of the sheet material, the conductive material held in the filling squeegee holder does not flow out, and the filling head can be lifted from the surface of the sheet material and moved to an arbitrary position. Is possible. By realizing such an operation of the filling head, it is possible to partially fill a portion of a via hole in a single sheet material, which has been difficult in the past, or to partially fill a different type of conductive material. .

  As described above, the conductive material filling device is a filling device that fills a via hole provided on the surface of a sheet material with a conductive material that melts at a temperature higher than room temperature, and is a conventional conductive paste filling device. Compared to the above, it is easy to handle and maintain the conductive material, and the filling device can be miniaturized and the utilization efficiency of the conductive material is enhanced.

  In the conductive material filling apparatus, as described in claim 2, the work heater is attached to the inside of the filling base, and is adsorbed to an edge of the upper surface of the filling base that holds the sheet material. It is preferable that a groove is provided. According to this, the sheet material placed on the upper surface of the filling base is sucked and stably held by the work chuck vacuum pump through the suction groove, and the work heater attached to the inside of the filling base is used. It can be heated efficiently.

  In the conductive material filling apparatus, as described in claim 3, a standby base in which cooling water can be circulated is arranged adjacent to the filling base so as to align the upper surface with the filling base. It is preferable to arrange | position. According to this, by moving the filling head that has been filled to the standby base, the conductive material melted in the filling squeegee holder is rapidly solidified so that the conductive material does not flow more than necessary. Can do.

  In the conductive material filling apparatus, as described in claim 4, the filling head includes a case plate facing a surface of the sheet material held by the filling base, and a packing on an end surface thereof, and the sheet material And a case side wall that forms a sealed space that can be evacuated together with the case plate, and the filling squeegee holder is preferably disposed inside the sealed space.

  Since the conductive material held in the filling squeegee holder is in a solid state, even if it is exposed to a high vacuum state, there is no problem of increase in viscosity as in a conventional conductive paste. For this reason, by making the sealed space in a high vacuum state, the conductive material melted on the surface of the sheet material can be defoamed in a high vacuum immediately before filling the via hole. Thereby, high-density filling without bubbles can be realized. Further, as compared with a conventional conductive paste filling device, it is possible to fill a deeper bottomed via.

  In the conductive material filling apparatus, as described in claim 5, the filling head is movable in a direction perpendicular to the surface of the sheet material held by the filling base, and has a squeegee at the tip. It is preferable to have a squeegee holder provided with.

  According to this, after the filling of the conductive material is completed, the filling head is moved in the horizontal direction with respect to the surface of the sheet material by the filling head feeding mechanism in a state where the squeegee is in contact with the surface of the sheet material. The surplus conductive material remaining on the surface of the sheet material can be scraped off and removed.

  The filling head feeding mechanism in the filling device includes, for example, a slide guide fixed to a base plate that holds the filling base horizontally and a slide portion that fits into the slide guide. A slide block, a guide shaft fixed to the slide block, a lifting block fitted to the guide shaft, and a lifting plate fixed to the lifting block. It can be set as the structure fixed to a plate.

  As described above, the conductive material filling device is a filling device that fills a via hole provided on the surface of a sheet material with a conductive material that melts at a temperature higher than room temperature, and is a conventional conductive paste filling device. Compared with this, the handling and maintenance management of the conductive material is easy, and the filling device is miniaturized and the utilization efficiency of the conductive material is enhanced.

  Therefore, as described in claim 7, the filling device is suitable when the sheet material is a sheet material used for manufacturing a multilayer circuit board in which a large number of via holes are formed in a large area. .

  The conductive material in the filling device is, for example, a metal filler and a low melting point solid dispersant that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. It can be set as the structure which consists of a mixture. In this case, it is preferable for handling that the melting point of the low melting point solid dispersant is 100 ° C. or lower.

  The invention described in claims 10 to 17 is an invention relating to a method of filling a conductive material using the filling device.

  The filling method according to claim 10, wherein the sheet material is held on the filling base in the filling device, and the surface of the sheet material is heated to the predetermined temperature or higher by the work heater, and the sheet material heating step, After the sheet material heating step, the filling head moving mechanism moves the filling head to the sheet material filling start position by the filling head feed mechanism, and after the filling head movement step, is held inside the filling squeegee holder. The conductive material is pressed against the surface of the sheet material by the pusher to melt the conductive material, and the filling head is moved against the surface of the sheet material by the filling head feed mechanism. Conduction that rubs the conductive material melted on the surface of the sheet material into the via hole by the filling squeegee while moving in the horizontal direction. It is characterized by being obtained and a fee charging step.

  According to this, as explained in the filling device according to claim 1, the conductive material that melts at a temperature higher than room temperature using the filling device according to claim 1 is provided on the surface of the sheet material. A filling method for filling a via hole, which is easier to handle and maintain a conductive material than a conventional conductive paste filling method, and can be a filling method with improved use efficiency of the conductive material. .

  As described in claim 11, when the filling device according to claim 4 is used, it is preferable that the sealed space is evacuated in the conductive material supplying step and the conductive material filling step. Thus, the effect described in the filling device according to the fourth aspect can be obtained. In this case, as described in claim 12, after the conductive material filling step, high vacuum defoaming of the conductive material supplied to the surface of the sheet material is not necessary, so the vacuum in the sealed space is released. Is preferred.

  When the filling device according to claim 5 is used, the filling head is in a state where the squeegee is brought into contact with the surface of the sheet material after the conductive material filling step. A surplus conductive material removing step of scraping and removing the surplus conductive material remaining on the surface of the sheet material while moving the filling head in a horizontal direction with respect to the surface of the sheet material by the feeding mechanism unit; It is preferable. Thus, the effect described in the filling device according to the fifth aspect can be obtained.

  As described in claim 14, when using the filling device according to claim 3, after the conductive material filling step, the filling head is moved to the standby base by the filling head feed mechanism. It is preferable to include a conductive material cooling step for cooling the conductive material held inside the filling squeegee holder. Thus, the effect described in the filling device according to the third aspect can be obtained.

  The effects of the filling method according to claims 15 to 17 are also as described in the filling device according to claims 7 to 9, and the description thereof is omitted.

It is a figure which shows an example of the filling apparatus which concerns on this invention, is a typical side view which shows the whole structure of the filling apparatus 100, and the principal part of the filling apparatus 100 is partially shown by the cross section. FIG. 2 is a sectional view taken along the two-dot chain line AA in FIG. 1 and shows details of the filling head 30. FIG. 3 is a cross-sectional view taken along the two-dot chain line BB in FIG. 2 and shows the shape of the filling portion at the tip of the filling head 30. FIG. 2 is a diagram schematically showing the difference between the state of heat entering and exiting the filling head 30 and the state of the conductive material 40 for “at the time of filling” and “at the time of filling” shown in FIG. 1. FIG. 10 is a diagram illustrating a parting operation of the conductive material 40a on the surface of the sheet material 11 by the squeegee 38 after the filling of the conductive material 40a is completed. (A) is typical sectional drawing which showed the mode of formation of the bottomed via (via hole which makes a conductor pattern the bottom) H to the sheet | seat material 10 surface, (b) is to bottomed via H It is sectional drawing which shows the mode of filling of the electrically conductive paste 4.

  The present invention relates to a conductive material filling apparatus for filling a via hole provided on a surface of a sheet material with a conductive material that melts at a predetermined temperature higher than room temperature, and a filling method using the same. Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of a filling apparatus according to the present invention, and is a schematic side view showing an overall configuration of a filling apparatus 100. In FIG. 1, the principal part of the filling apparatus 100 is partially shown in cross section. FIG. 2 is a sectional view taken along the two-dot chain line AA in FIG. 1 and shows details of the filling head 30. FIG. 3 is a cross-sectional view taken along the two-dot chain line BB in FIG. 2 and shows the shape of the filling portion at the tip of the filling head 30. FIG. 4 is a diagram schematically showing the difference between the state of heat entering and exiting the filling head 30 and the state of the conductive material 40 for “when filling” and “when waiting for filling” shown in FIG. FIG. 5 is a diagram illustrating an operation for removing excess conductive material 40a on the surface of the sheet material 11 by the squeegee 38 after the filling of the conductive material 40a is completed.

  A filling apparatus 100 shown in FIG. 1 is a filling apparatus for a conductive material 40 that fills a via hole (bottomed via) H provided on the surface of a sheet material 11 with a conductive material 40 that melts at a predetermined temperature higher than room temperature. is there. The sheet material 11 which is a work of the filling apparatus 100 is the same as the sheet material 10 in FIG. 6, and the same portions are denoted by the same reference numerals.

  In the sheet material 10 of FIG. 6, the metal (copper) foil 2 is bonded to one surface of the resin film 1 made of a thermoplastic resin, and the protective film 3 is bonded to the opposite surface. Although the protective film is not bonded to the resin film 1 of the sheet material 11 shown in FIG. 1, the protective film may or may not be present. Further, the copper foil 2 in the sheet material 11 of FIG. 1 is actually processed into a predetermined conductor pattern as in the case of the sheet material 10 shown in FIG. 6, but is simplified in FIG.

  Further, the conductive material 40 in the filling device 100 of FIG. 1 is a mixture of, for example, a metal filler and a low-melting-point solid dispersant that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. Can do. In this case, it is preferable that the low melting point solid dispersant has a melting point of 100 ° C. or lower for handling.

  The filling device 100 for the conductive material 40 shown in FIG. 1 includes three main parts including a work holding mechanism unit 20, a filling head 30, and a filling head feed mechanism unit 50.

  The work holding mechanism 20 which is the first main part includes a filling base 21 for holding the sheet material 11 and a conductive material 40 supplied to the surface of the sheet material 11 held by the filling base 21 at a melting temperature. A work heater 22 capable of heating as described above is provided. By heating the sheet material 11 by the work heater 22, the conductive material 40 in a solid state at room temperature is melted by heat transfer from the sheet material 11 to become a flowable conductive material 40 a.

  The work holding mechanism 20 will be described in more detail. The filling base 21 is supported by the base column 24 with respect to the base plate 23 so that the upper surface is horizontal. Adsorption grooves 25 are provided at the edge of the upper surface of the filling base 21 that holds the sheet material 11. The suction groove 25 is connected to the work chuck vacuum pump 26 by piping shown by a bold line. Accordingly, the sheet material 11 placed on the upper surface of the filling base 21 can be vacuum-sucked by the work chuck vacuum pump 26 via the suction groove 25 and stably held. Moreover, the workpiece | work heater 22 is attached inside the filling base 21, and can heat the sheet | seat material 11 efficiently.

  Further, in the filling device 100 of FIG. 1, a standby base 27 through which cooling water 28 can circulate is disposed adjacent to the filling base 21 so as to align the upper surface with the filling base 21. As will be described later, by moving the filling head 30 that has been filled with the conductive material 40a to the standby base 27, the conductive material 40a melted in the filling squeegee holder 31 is rapidly solidified, and the conductive material 40a is required. It can be prevented from flowing out.

  The filling head 30 which is the second main part supplies the conductive material 40 to the surface of the sheet material 11 held by the filling base 21, and the conductive material 40 a made flowable by heat transfer from the sheet material 11, The via hole H formed in the sheet material 11 is filled.

  More specifically, the filling head 30 has a filling squeegee holder 31. The filling squeegee holder 31 includes a pusher 32 that holds the conductive material 40 in a solid state at room temperature and moves the solid conductive material 40 in a direction perpendicular to the surface of the sheet material 11. Moreover, the filling squeegee holder 31 includes a filling squeegee 33 on the end surface that contacts the surface of the sheet material 11 as shown in FIGS. 2 and 3. The filling squeegee 33 rubs the conductive material 40 a supplied to the surface of the sheet material 11 and made flowable into the via hole H. As will be described later, the filling squeegee holder 31 can swing in the horizontal direction with respect to the surface of the sheet material 11.

  Moreover, in the filling apparatus 100 of FIG. 1, the filling head 30 has the case plate 34 and the case side wall 35 which comprise the sealed space M which can be evacuated. The case plate 34 faces the surface of the sheet material 11 held by the filling base 21, and the case side wall 35 includes a packing 36 on an end surface that contacts the surface of the sheet material 11. The filling squeegee holder 31 is disposed in a sealed space M composed of a case plate 34 and a case side wall 35. The sealed space M is connected to the filling chamber vacuum pump 37 by piping shown by a thick line, and the sealed space M is exhausted to a high vacuum by the filling chamber vacuum pump 37.

  The details around the filling head 30 will be described in more detail with reference to FIG. 2. A motor plate 34 m and a guide plate 34 g are fixed to the upper surface of the case plate 34 via struts. A swing motor YM is fixed to the motor plate 34m, and a swing eccentric shaft YS is fixed to the shaft end by a joint (not shown). A swing timing pulley YP is attached to the swing eccentric shaft YS. On the other hand, a rotation guide KG is fixed to the guide plate 34g, an eccentric shaft KS is rotatably attached to the rotation guide KG, and a timing pulley KP is fixed to the eccentric shaft KS. The timing pulley KP is connected to the swing timing pulley YP and the timing belt TB. When the swing eccentric shaft YS is rotated, the eccentric shaft KS is also rotated in conjunction with the rotation. On the upper surface of the filling squeegee holder 31, the eccentric portions of the swing eccentric shaft YS and the eccentric shaft KS are rotatably fitted. Thereby, the filling squeegee holder 31 swings back and forth and right and left in accordance with the rotation of the swing eccentric shaft YS and the eccentric shaft KS.

  As described above, the filling squeegee 33 is fixed to the lower surface of the filling squeegee holder 31. As shown in FIG. 3, the filling squeegee 33 has an oval shape. A pusher 32 is provided inside the filling squeegee holder 31 so as to be vertically movable by air. A stick-like conductive material 40 that is in a solid state at room temperature is set in the space formed by the lower surface of the pusher 32, the filling squeegee holder 31, and the filling squeegee.

  In the filling apparatus 100 shown in FIG. 1, the filling head 30 has a squeegee holder 39. The squeegee holder 39 is movable in the direction perpendicular to the surface of the sheet material 11 held on the filling base 21 by the squeegee lifting cylinder SS, and a squeegee 38 is attached to the tip. As shown in FIG. 5, after the filling of the conductive material 40 a is completed, the filling head 30 of the sheet material 11 is moved by the filling head feed mechanism 50 described below in a state where the squeegee 38 is in contact with the surface of the sheet material 11. By moving in the horizontal direction with respect to the surface, it is possible to scrape and remove excess conductive material 40a remaining on the surface of the sheet material 11.

  The filling head feeding mechanism unit 50 as the third main part moves the filling head 30 in the horizontal direction and the vertical direction with respect to the surface of the sheet material 11.

  More specifically, the filling head feed mechanism 50 in the filling apparatus 100 of FIG. 1 includes a slide guide 51 fixed to a base plate 23 that holds the filling base 21 horizontally, and a slide portion that fits the slide guide 51. And a slide block 52 provided with 52s. A screw nut 53n of a feed screw 53 is fixed to the slide block 52. The feed screw 53 is rotatably supported at both ends by guides 53g. One end of the feed screw 53 is fixed to the feed motor 53m by a joint (not shown), and the slide block 52 can be moved in the left-right direction in FIG. 1 by the rotation of the feed motor 53m.

  Further, as shown in FIG. 2, the filling head feeding mechanism section 50 is fitted on a guide shaft 54g, an elevating cylinder 54s fixed to each slide block 52, and a guide shaft 54g on both sides of the filling head 30 to move up and down. And an elevating block 55b movable in the direction. The shaft end of the lifting cylinder 54s is fixed to the lower end of the lifting block 55b, and the lifting block 55b can be moved up and down by operation of the lifting cylinder 54s. The filling head feed mechanism 50 has a lifting plate 55p that connects and fixes the lifting blocks 55b on both sides, and the filling head 30 is fixed to the lifting plate 55p. With the above configuration, the filling head feeding mechanism unit 50 can move the filling head 30 in the horizontal direction and the vertical direction with respect to the surface of the sheet material 11.

  The filling device 100 shown in FIGS. 1 to 4 is a filling device that fills the via hole H provided on the surface of the sheet material 11 with the conductive material 40 that melts at a predetermined temperature higher than room temperature. In other words, the filling apparatus 100 heats the conductive material 40 in a solid state at room temperature to the predetermined temperature or more to melt the conductive material 40 and then the via hole H provided on the surface of the sheet material 11. To fill. For this reason, in the filling apparatus 100, the work holding mechanism unit 20 is provided with a work heating heater 22, and the work heating heater 22 heats the sheet material 11 held on the filling base 21 and supplies it to the surface thereof. The conductive material 40 is melted. The conductive material 40 is sticked in a solid state at room temperature (hereinafter referred to as “stick conductive material”) and is held in the filling squeegee holder 31 of the filling head 30, and the stick conductive material 40 is held by the pusher 32. It is pressed against the surface of the sheet material 11. As a result, the tip portion is melted by heat conduction from the surface of the sheet material 11, and the melted conductive material 40 a is supplied to the surface of the sheet material 11. While the filling head 30 is moved in the horizontal direction with respect to the surface of the sheet material 11 by the filling head feed mechanism unit 50, the molten conductive material 40 a supplied to the surface of the sheet material 11 is transferred to the via hole by the filling squeegee 33. Rub into H. As a result, the conductive material 40 a is filled in the via hole H provided on the surface of the sheet material 11.

  Since the filling device 100 can use the conductive material 40 that melts at a temperature higher than room temperature (in other words, the conductive material 40 in a solid state at room temperature), the filling device 100 flows at the conventional room temperature described in FIG. Problems associated with the use of the conductive paste 4 can be eliminated. That is, since the stick conductive material 40 held in the filling squeegee holder 31 of the filling device 100 is in a solid state, unlike the conventional conductive paste 4, vacuum defoaming or stirring in the filling squeegee holder 31 is not required. A stable composition can be maintained over a long period of time. Moreover, since vacuum degassing and stirring are not required, the filling head 30 can also be reduced in size.

  The amount of the stick conductive material 40 held in the filling squeegee holder 31 can be set to an arbitrary volume according to the filling amount, and a plurality of sheet materials 11 can be continuously filled. In addition, when the sheet material 11 is filled, the amount of the molten conductive material 40a supplied to the surface of the sheet material 11 is controlled by appropriately controlling the pressing force of the pusher 32 against the sheet material 11 of the stick conductive material 40. Can be limited to the minimum required. For example, when filling 50,000 to 50,000 bottomed vias (via holes having a conductor pattern as a bottom) in the sheet material 11 of 450 mm square, the amount of the melted conductive material 40a supplied to the surface of the sheet material 11 is determined. , About 5 g. This corresponds to about 1/400 of the usage amount of the conventional conductive paste 4 described in FIG.

  In the filling squeegee holder 31 of the filling head 30 remote from the surface of the sheet material 11 after the filling, the conductive material 40a at the tip end portion that has been melted returns to the solid state again, so the filling squeegee 33 is adjusted to the next cycle. Can be easily cleaned. Moreover, useless consumption of the conductive material 40 accompanying this cleaning does not occur.

  Further, in the filling device 100 for the conductive material 40, the filling head 30 is placed at an arbitrary position of the sheet material 11 by downsizing the filling head 30 and using the conductive material 40 in a solid state at room temperature. It is possible to move and fill. In the conventional filling head using the conductive paste 4 that can flow at room temperature described in FIG. 6, the surface of the sheet material 10 functions as a bottom plate for holding the conductive paste 4 in the filling head. It was necessary to move so as to slide the surface of the sheet material 10. However, in the filling device 100 of the conductive material 40 shown in FIGS. 1 to 4, when the filling head 30 is away from the surface of the sheet material 11, the conductive material 40 held in the filling squeegee holder 31 is , In a solidified state. Therefore, even if the filling head 30 is separated from the surface of the sheet material 11, the conductive material 40 held in the filling squeegee holder 31 does not flow out. It is possible to move to a position. By realizing such an operation of the filling head 30, a part of the many via holes H in the sheet material 11, which has been difficult in the past, is partially filled or partially filled with a different kind of conductive material 40. Is possible.

  Furthermore, in the filling device 100 for the conductive material 40 shown in FIGS. 1 to 4, the conductive material 40 held in the filling squeegee holder 31 is in a solid state. The problem of a viscosity increase like the conventional conductive paste 4 described does not occur. For this reason, the sealed space M composed of the case plate 34 and the case side wall 35 is brought into a high vacuum state, so that the conductive material 40 a melted on the surface of the sheet material 11 is removed from the high vacuum immediately before filling the via hole H. Can foam. Thereby, high-density filling without bubbles can be realized. Further, it is possible to fill a deeper bottomed via as compared with the conventional filling device of the conductive paste 4 described in FIG.

  As described above, the filling device 100 for the conductive material 40 shown in FIGS. 1 to 4 fills the via hole H provided on the surface of the sheet material 11 with the conductive material 40 that melts at a temperature higher than room temperature. Compared to the conventional conductive paste 4 filling device described with reference to FIG. 6, the apparatus is easier to handle and maintain the conductive material 40, is miniaturized, and increases the utilization efficiency of the conductive material 40. It has become a filling device.

  Therefore, the filling device 100 is suitable when the sheet material 11 shown in FIGS. 1 to 4 is a sheet material used for manufacturing a multilayer circuit board in which a large number of via holes are formed in a large area. .

  Next, an outline of a filling method of the conductive material 40 using the filling device 100 will be described.

  The filling method of the conductive material 40 using the filling apparatus 100 shown in FIGS. 1 to 4 has four main steps including a sheet material heating step, a filling head moving step, a conductive material supplying step, and a conductive material filling step. ing. In the sheet material heating step, the sheet material 11 is held on the filling base 21 in the filling device 100 of FIG. 1, and the work heater 22 heats the surface of the sheet material 11 to a predetermined temperature or higher at which the conductive material 40 melts. In the filling head moving step, after the sheet material heating step, the filling head feeding mechanism unit 50 moves the filling head 30 to the filling start position of the sheet material 11. In the conductive material supply step, after the filling head moving step, the conductive material 40 held inside the filling squeegee holder 31 is pressed against the surface of the sheet material 11 by the pusher 32 to melt the conductive material 40. The state is changed to the flowing conductive material 40a. In the conductive material filling step, the filling head 30 is moved in the horizontal direction with respect to the surface of the sheet material 11 by the filling head feeding mechanism 50, and the conductive material 40 a melted on the surface of the sheet material 11 is filled into the via hole by the filling squeegee 33. Rub into H.

  The filling apparatus 100 shown in FIGS. 1 to 4 is used, and the filling method comprising the above four main steps is compared with the conventional filling method of the conductive paste 4 explained in FIG. In addition, it is easy to handle and maintain the conductive material 40, and the filling method can improve the utilization efficiency of the conductive material 40.

  The filling apparatus 100 shown in FIGS. 1 to 4 has a sealed space M in the conductive material supplying step and the conductive material filling step because the filling head 30 has a sealed space M composed of a case plate 34 and a case side wall 35. It is preferable to evacuate M. Thus, as described above, the conductive material 40a melted on the surface of the sheet material 11 can be degassed in a high vacuum immediately before filling the via hole H, and high density filling without bubbles can be realized. In this case, since the high vacuum defoaming of the conductive material 40a supplied to the surface of the sheet material 11 is not required after the conductive material filling step, it is preferable to release the vacuum in the sealed space M.

  1 to 4 includes a standby base 27 in which cooling water 28 can be circulated, adjacent to the filling base 21, so that the conductive material filling step is performed after the conductive material filling step. The filling head feeding mechanism 50 moves the filling head 30 to the standby base 27, and preferably includes a conductive material cooling step for cooling the conductive material 40a held in the filling squeegee holder 31. Thus, the conductive material 40a melted in the filling squeegee holder 31 can be rapidly solidified so that the conductive material 40a does not flow out more than necessary.

  Furthermore, since the squeegee 38 is attached to the filling head 30, the filling apparatus 100 shown in FIGS. 1-4 is set as the structure which has a surplus conductive material removal process after the said conductive material filling process. That is, in the surplus conductive material removing step, while the squeegee 38 is in contact with the surface of the sheet material 11, the filling head 30 is moved in the horizontal direction with respect to the surface of the sheet material 11 by the filling head feed mechanism unit 50. The surplus conductive material 40a remaining on the surface of the sheet material 11 can be scraped off and removed.

  Next, the filling method of the conductive material 40 using the filling device 100 will be described with a specific example.

  The filling apparatus 100 shown in FIGS. 1 to 4 includes a work holding mechanism unit 20 that holds the filling surface of the sheet material 11 that is a work in an upward direction, and a conductive material while keeping the filling surface of the sheet material 11 in vacuum. The filling head 30 is filled with three parts, a filling head feeding mechanism 50 that moves the filling head 30, and a controller (not shown) that controls them. The filling operation of the conductive material 40 using the filling apparatus 100 is basically performed by the following seven-step operation. That is, the first step: holding and heating the flat surface of the sheet material 11, the second step: moving the filling head 30 to the filling start position, the third step: evacuating the filling head 30 and pressurizing and melting the stick conductive material 40 Defoaming of the conductive material 40a, fourth step: moving to the filling end position of the filling head 30 and filling the conductive material 40a into the via hole (bottom via) H during that time, fifth step: inside the filling head 30 The sixth step is to move the filling head 30 to the standby base 27 to cool the stick conductive material 40, and the seventh step is to remove the sheet material 11.

  Hereinafter, specific operations and operation amounts will be described.

  The stick conductive material 40 used was a metal powder (metal filler) of silver (Ag) and tin (Sn) added with 8 wt% of paraffin having a melting point of 43 ° C., kneaded and molded into a stick shape. In addition, the sheet material 11 which is a workpiece is a sheet material used for manufacturing a multilayer circuit board, and is provided with about 40,000 vias (bottom vias) H having a size of 450 mm square and a size of Φ100 × 50 μm. I used what is.

  The sheet material 11 was placed on the filling base 21 and was planarly adsorbed by a work chuck vacuum pump 26. Next, the sheet material 11 was heated above the melting point of the stick conductive material 40 (specifically, 60 ° C.) by the work heater 22 built in the filling base 21. Next, the filling head 30 is moved to the filling start position on the sheet material 11, pressurized air is supplied to the filling squeegee holder 31 of the filling head 30, and the stick conductive material 40 by the pusher 32 is applied to the surface of the sheet material 11. The conductive material 40a that can flow by pressing and melting the tip was supplied to the surface of the sheet material 11.

  With the above operation, the filling head 30 is ready for filling. Therefore, the sealed space M formed by the case plate 34 and the case side wall 35 of the filling head 30 is evacuated, the swing motor YM is rotated, and the swing squeegee 33 swings. Stirring operation was started, defoaming was started before filling, and vacuum filling was performed. Defoaming before the start of filling was performed at −98 kPa for 10 seconds, the filling speed was 20 mm / sec, the degree of vacuum was −98 kPa similar to the defoaming pressure, and the sheet material 11 was reciprocated three times. The final half-reciprocation of the filling was a parting speed of 60 mm / sec, and the recess in the via hole H on the finished surface was 1 μm or less.

  After completion of the filling operation, the swing motor YM is stopped to stop the swing stirring operation of the filling squeegee 33, the filling chamber vacuum pump 37 is stopped, and the vacuum state in the sealed space M of the filling head 30 is released. By sliding the filling head 30 onto the standby base 27, the molten conductive material 40a in the filling squeegee holder 31 was solidified.

  Next, the elevating cylinder 54s was raised to lift the filling head 30 from the standby base 27, and the filling head 30 was moved to the right end position of the sheet material 11 shown in FIG. Next, as shown in FIG. 5, the squeegee elevating cylinder SS is lowered and the squeegee 38 is lightly brought into contact with the surface of the sheet material 11 to move the filling head 30 leftward at a speed of 60 mm / sec. Excess conductive material 40a on the surface of the material 11 was removed. Finally, the work chuck vacuum pump 26 was stopped, and the sheet material 11 as a work was taken out.

  With the above operation, the filling of the conductive material 40 into the via hole (bottom via) H of the sheet material 11 was completed.

  In the filling method of the conductive material 40 using the filling device 100, by using the conductive material 40 in a solid state at room temperature, one sheet material 11 can be filled or a plurality of wafer sheets 11 can be filled continuously. Even if it is used, it is not necessary to consider contamination due to long-term use of the conductive paste 4 or compositional deviation due to defoaming unlike the conventional filling method using the conductive paste 4 described in FIG. High density packing underneath is now possible.

  As for the cleaning of the filling head, the conventional filling head using the conductive paste requires periodic maintenance work for cleaning the large filling chamber after the conductive paste is collected. On the other hand, since the filling head 30 of the filling device 100 is cleaned by bringing the conductive material 40 in a solid state into contact with the sheet material 11 to melt and fluidize, the cleaning around the filling squeegee 33 is performed by a solder printer. It is possible to use a paper wiping mechanism similar to that used for mask cleaning and a wet cleaning mechanism using alcohol. For this reason, by adding automatic cleaning to the filling apparatus 100 of FIG. 1, automatic cleaning can be performed for each filling operation, and continuous operation of the filling apparatus 100 can also be realized.

  Further, the sheet material 11 after filling is also removed from the work holding mechanism portion 20, whereby the sheet material 11 is cooled and the conductive material 40 a filled in the via hole H is solidified. Significant advantages such as no scattering or falling off due to drying of the conductive paste 4 found in the conventional conductive paste 4 can be obtained, and productivity can be improved and resources can be saved.

  In the above specific examples, paraffin having a melting point of 43 ° C. is used as a component that contributes to melting of the conductive material 40 in terms of work safety and equipment environment. However, depending on the purpose and application, melting contributing components other than paraffin are used. Can be adopted as appropriate. Further, the shape of the conductive material 40 is not limited to a stick shape, and may be, for example, a powder shape.

  As described above, a conductive material filling apparatus and a filling method using the same include a filling apparatus that fills a via hole provided on the surface of a sheet material with a conductive material that melts at a temperature higher than room temperature. Compared with the conventional conductive paste filling device and the filling method using the same, the handling and maintenance of the conductive material is easier, the filling device is downsized and the conductive material is used. It is a filling device with improved efficiency and a filling method using the same.

100 Filling device 11 Sheet material H Via hole (via with bottom)
DESCRIPTION OF SYMBOLS 20 Work holding | maintenance mechanism part 21 Filling base 22 Work heating heater 30 Filling head 31 Filling squeegee holder 32 Pusher 33 Filling squeegee 40 (solid state) conductive material (stick conductive material)
40a (molten) conductive material 50 filling head feed mechanism

Claims (17)

A conductive material filling apparatus that fills a via hole provided on a surface of a sheet material with a conductive material that melts at a predetermined temperature higher than room temperature,
A work holding mechanism comprising: a filling base for holding the sheet material; and a work heater capable of heating the conductive material supplied to the surface of the sheet material held on the filling base to a temperature equal to or higher than the predetermined temperature. When,
Supplying the conductive material to the surface of the sheet material held by the filling base, and filling the via hole with the conductive material;
A filling head feeding mechanism for moving the filling head in a horizontal direction and a vertical direction with respect to the surface of the sheet material;
The filling head comprises:
A filling squeegee that contacts the surface of the sheet material and rubs the conductive material supplied to the surface of the sheet material into the via hole is provided on an end surface,
It can swing in the horizontal direction with respect to the surface of the sheet material,
A pusher that holds the conductive material in a solid state at room temperature therein and moves the solid conductive material in a direction perpendicular to the surface of the sheet material,
A conductive material filling apparatus comprising a filling squeegee holder. The work heater is attached to the inside of the filling base,
2. The conductive material filling apparatus according to claim 1, wherein an adsorption groove is provided at an edge of an upper surface of the filling base for holding the sheet material.   The conductive material according to claim 1, wherein a standby base capable of circulating cooling water therein is disposed adjacent to the filling base so as to align the upper surface with the filling base. Filling equipment. The filling head comprises:
A case plate facing the surface of the sheet material held by the filling base;
A packing is provided on the end face, and has a case side wall that forms a sealed space that can be evacuated together with the case plate in contact with the surface of the sheet material,
4. The conductive material filling apparatus according to claim 1, wherein the filling squeegee holder is disposed inside the sealed space. 5. The filling head comprises:
5. The squeegee holder that is movable in a direction perpendicular to the surface of the sheet material held on the filling base and has a squeegee at the tip thereof. 6. The conductive material filling apparatus as described. The filling head feed mechanism is
A slide guide fixed to a base plate for holding the filling base horizontally, and a slide block having a slide portion fitted to the slide guide;
A guide shaft fixed to the slide block; a lifting block fitted to the guide shaft;
A lifting plate fixed to the lifting block,
The conductive material filling device according to claim 1, wherein the filling head is fixed to the elevating plate.   The said sheet | seat material is a sheet | seat material used for manufacture of a multilayer circuit board, The filling apparatus of the electrically-conductive material as described in any one of the Claims 1 thru | or 6 characterized by the above-mentioned. The conductive material is
It consists of a mixture of a metal filler and a low melting point solid dispersant that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. The conductive material filling apparatus as described.   9. The conductive material filling apparatus according to claim 8, wherein the low melting point solid dispersant has a melting point of 100 [deg.] C. or less. A conductive material filling apparatus that fills a via hole provided on a surface of a sheet material with a conductive material that melts at a predetermined temperature higher than room temperature,
A work holding mechanism comprising: a filling base for holding the sheet material; and a work heater capable of heating the conductive material supplied to the surface of the sheet material held on the filling base to a temperature equal to or higher than the predetermined temperature. When,
Supplying the conductive material to the surface of the sheet material held by the filling base, and filling the via hole with the conductive material;
A filling head feeding mechanism for moving the filling head in a horizontal direction and a vertical direction with respect to the surface of the sheet material;
The filling head comprises:
A filling squeegee that contacts the surface of the sheet material and rubs the conductive material supplied to the surface of the sheet material into the via hole is provided on an end surface,
It can swing in the horizontal direction with respect to the surface of the sheet material,
A conductive material having a filling squeegee holder, which has a pusher for holding the conductive material in a solid state at room temperature therein and moving the solid conductive material in a direction perpendicular to the surface of the sheet material. A filling method using a filling device,
A sheet material heating step of holding the sheet material on the filling base and heating the surface of the sheet material to the predetermined temperature or higher by the work heater;
After the sheet material heating step, a filling head moving step of moving the filling head to a filling start position of the sheet material by the filling head feeding mechanism unit;
After the filling head moving step, a conductive material supply step of melting the conductive material by pressing the conductive material held inside the filling squeegee holder against the surface of the sheet material by the pusher;
Conductive material filling in which the conductive material melted on the surface of the sheet material is rubbed into the via hole by the filling squeegee while the filling head is moved in the horizontal direction with respect to the surface of the sheet material by the filling head feed mechanism. A process for filling a conductive material, characterized by comprising the steps of: The filling head includes a case plate facing the surface of the sheet material held on the filling base, and a packing on the end surface, and constitutes a sealed space that can be vacuumed together with the case plate in contact with the surface of the sheet material And a filling head in which the filling squeegee holder is disposed inside the sealed space,
The method for filling a conductive material according to claim 10, wherein the sealed space is evacuated in the conductive material supply step and the conductive material filling step.   The method for filling a conductive material according to claim 11, wherein after the step of filling the conductive material, the vacuum in the sealed space is released. The filling head is capable of moving in a direction perpendicular to the surface of the sheet material held on the filling base, and has a squeegee holder provided with a squeegee at the tip,
After the conductive material filling step, the sheet material is moved in the horizontal direction with respect to the surface of the sheet material by the filling head feeding mechanism portion in a state where the squeegee is in contact with the surface of the sheet material. 13. The method of filling conductive material according to claim 10, further comprising a surplus conductive material removing step of scraping and removing surplus conductive material remaining on the surface of the conductive material. The filling device is a filling device in which a standby base through which cooling water can be circulated is arranged adjacent to the filling base so as to align the upper surface with the filling base.
After the conductive material filling step, the conductive material cooling step of cooling the conductive material held inside the filling squeegee holder by moving the filling head to the standby base by the filling head feed mechanism. The method for filling a conductive material according to claim 10, wherein the conductive material is filled with a conductive material.   The method for filling a conductive material according to any one of claims 10 to 14, wherein the sheet material is a sheet material used for manufacturing a multilayer circuit board. The conductive material is
It consists of a mixture of a metal filler and a low melting point solid dispersant that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. The conductive material filling method described.   The method for filling a conductive material according to claim 16, wherein the low melting point solid dispersant has a melting point of 100 ° C. or lower.

Images