JP5402784B2 - Method for manufacturing substrate sheet with conductive bump and method for manufacturing multilayer printed wiring board - Google Patents

Description

  The present invention relates to a method for producing a substrate sheet with conductive bumps and a method for producing a multilayer printed wiring board.

  Conventionally, an insulating sheet such as a prepreg and an additional board sheet are superimposed on a board sheet with conductive bumps in which a plurality of substantially conical conductive bumps are formed on the surface of a board sheet made of metal foil such as copper foil. A multilayer printed wiring board formed by being combined is known. In such a multilayer printed wiring board, when the conductive bump formed on the surface of the substrate sheet penetrates the insulating sheet, the substrate sheets on both sides of the insulating sheet are electrically connected by the conductive bump. (See, for example, Patent Documents 1 to 3).

  In the conventional method for manufacturing a substrate sheet with conductive bumps as shown in Patent Documents 1 to 3, etc., a substantially conical conductive bump is formed on the substrate sheet by a screen printing method using a screen plate having a plurality of through holes. Forming. However, when conductive bumps are formed on a substrate sheet by a screen printing method, a conductive bump having a desired height cannot be obtained by one printing, and the conductive bumps cannot penetrate the insulating sheet. The conductive bumps are formed by performing several times of overprinting. Here, in each printing, the position of the conductive bump on the substrate sheet and the through hole of the screen plate are aligned, the conductive paste is transferred to the substrate sheet, and the conductive paste is applied on the substrate sheet. Since a series of steps including drying of the substrate sheet after the transfer has to be performed, there is a problem that it takes time to manufacture the substrate sheet with conductive bumps.

  In Patent Document 4, in the screen printing method, solder is filled in the through holes of the screen plate in the initial state, and solder films are formed on both side surfaces of the through holes, and then the solder is applied to the substrate sheet. Techniques such as transcription are described. However, the method shown in Patent Document 4 improves the shortage of solder supply in the initial stage of printing, and the time required for printing in the second and subsequent printings is different compared to the conventional screen printing method. There is no problem.

Japanese Patent No. 3167840 Japanese Patent No. 4127492 JP 2002-305376 A Japanese Patent No. 3384414

  The present invention has been made in consideration of the above points, and aligns a portion where a conductive bump is to be formed on a substrate sheet with a through hole of a screen plate, and transfers the conductive paste to the substrate sheet. , And the number of times a series of steps consisting of drying the substrate sheet after transferring the conductive paste onto the substrate sheet can be reduced, so that the time required to manufacture the substrate sheet with conductive bumps can be reduced. It aims at providing the manufacturing method of the board | substrate sheet | seat with an electroconductive bump which can be shortened.

  Moreover, this invention shortens the time required in order to manufacture a multilayer printed wiring board by using the board sheet with a conductive bump manufactured by the manufacturing method of the board sheet with a conductive bump as mentioned above. It aims at providing the manufacturing method of the multilayer printed wiring board which can be manufactured.

  The method for producing a substrate sheet with conductive bumps according to the present invention comprises a step of preparing a screen plate provided with a plurality of through holes, and pressing the conductive paste on the screen plate into the through holes of the screen plate. The conductive paste is transferred onto the substrate sheet below the screen plate through the through hole, and the substrate sheet on which the conductive paste is transferred is dried to form conductive bumps on the substrate sheet. After transferring the conductive paste onto the substrate sheet, filling the through hole of the screen plate with the conductive paste, and filling the through hole of the screen plate with the conductive paste, The conductive paste on the screen plate is pressed against the through hole of the screen plate, and the lead of the substrate sheet is passed through the through hole. And transferring the conductive paste on sex bump, and wherein a conductive paste on the conductive bumps and a step of drying the substrate sheet has been transferred.

  According to the method for manufacturing a substrate sheet with conductive bumps of the present invention, after transferring the first conductive paste onto the substrate sheet, the screen plate penetrates in the transfer of the conductive paste to the substrate sheet for the second and subsequent times. The holes are filled with a conductive paste in advance, and then the conductive paste is transferred to the substrate sheet using this screen plate. Therefore, a larger amount of the conductive paste can be transferred to the substrate sheet as compared with the case where the conductive paste is transferred to the substrate sheet without filling the through hole of the screen plate with the conductive paste. Larger conductive bumps can be formed on the substrate sheet by a single screen printing. As a result, the position of the conductive bumps on the substrate sheet to be aligned with the through holes of the screen plate, the transfer of the conductive paste to the substrate sheet, and the transfer of the conductive paste onto the substrate sheet The number of times of performing a series of steps including drying of the substrate sheet can be reduced. For this reason, the time required to manufacture the substrate sheet with conductive bumps can be shortened.

  In the method for producing a substrate sheet with conductive bumps of the present invention, after transferring the conductive paste onto the substrate sheet, the step of filling the through hole of the screen plate with the conductive paste, the penetration of the screen plate After filling the hole with the conductive paste, the conductive paste on the screen plate is pressed onto the through hole of the screen plate by pressing the conductive paste on the screen plate onto the conductive bump of the substrate sheet. It is preferable to carry out a series of steps consisting of a step of transferring the substrate and a step of drying the substrate sheet having the conductive paste transferred onto the conductive bumps once or a plurality of times.

  In the method for producing a substrate sheet with conductive bumps of the present invention, when transferring the conductive paste onto the substrate sheet, the conductive paste on the screen plate is pressed into the through hole of the screen plate by a pressing member. Then, when the conductive paste is filled in the through hole of the screen plate, the pressing paste may be filled with the conductive paste in the through hole of the screen plate.

  Alternatively, when the conductive paste is transferred onto the substrate sheet, the conductive paste on the screen plate is pressed against the through hole of the screen plate by the first pressing member, When filling the conductive paste, the through hole of the screen plate may be filled with the conductive paste by a second pressing member provided integrally with the first pressing member.

  At this time, when the combination of the first pressing member and the second pressing member moves in one direction on the screen plate, the conductive paste is formed on the substrate sheet by the first pressing member. When the assembly moves on the screen plate in the other direction opposite to the one direction, the second pressing member causes the conductive paste to pass through the through hole of the screen plate. It may be designed to be filled. In this case, the conductive paste is transferred onto the substrate sheet when the combination of the first pressing member and the second pressing member moves in one direction from the initial position, and then the combination is in one direction. Since the conductive paste can be filled in the through hole of the screen plate when moving in the reverse direction and returning to the initial position, the transfer of the conductive paste onto the substrate sheet by one reciprocation of the combination and The conductive paste can be filled into the through holes of the screen plate. For this reason, it is possible to further reduce the time required for manufacturing the conductive bumped substrate sheet.

In the method for producing a substrate sheet with conductive bumps of the present invention, the tension of the screen and the pressing pressure of the pressing member when the conductive paste is transferred onto the substrate sheet are transferred to the through holes of the screen plate. It may be the same as the tension of the screen and the pressing pressure of the pressing member when filling the adhesive paste. In this case, preferably, a value obtained by dividing the tension of the screen plate by the width of the screen plate is in the range of 1.4 to 3.6 N / mm, and the pressing pressure of the pressing member is set to the pressing member. The value divided by the width is in the range of 0.3 to 0.9 N / mm.

In the method for manufacturing a substrate sheet with conductive bumps of the present invention, the screen plate is stretched by a pair of stretching tools, the stretching tool sandwiches the screen plate, and the mounting tool. And a reinforcing plate interposed between the screen plates. In this case, the thickness of the reinforcing plate is preferably the same as the thickness of the screen plate or larger than the thickness of the screen plate.

  In the method for manufacturing a substrate sheet with conductive bumps of the present invention, at least one of the pair of stretching tools is movable in the vertical direction, and is supported by the at least one stretching tool. The vertical distance between one end of the screen plate and the substrate sheet may be in the range of 0.5 to 10 mm.

  In the method for producing a substrate sheet with conductive bumps of the present invention, the temperature and humidity in the vicinity of the screen plate may be kept constant by a temperature adjusting mechanism that covers the screen plate from above.

  The method for producing a multilayer printed wiring board according to the present invention comprises a step of preparing a screen plate provided with a plurality of through holes, and pressing the conductive paste on the screen plate against the through holes of the screen plate. A process of forming a conductive bump on the substrate sheet by transferring the conductive paste onto the substrate sheet below the screen plate through the through hole and drying the substrate sheet to which the conductive paste has been transferred. And after transferring the conductive paste onto the substrate sheet, filling the through hole of the screen plate with the conductive paste, and after filling the through hole of the screen plate with the conductive paste, the screen The conductive paste on the plate is pressed through the through hole of the screen plate by pressing the conductive paste on the plate against the through hole of the screen plate. A step of transferring a conductive paste onto the substrate, a step of drying the substrate sheet having the conductive paste transferred onto the conductive bump, and a conductive formed by transferring the conductive paste a plurality of times. A step of superimposing an insulating sheet on a substrate sheet with conductive bumps having bumps, sandwiching and heating the superposed body, and allowing the conductive bumps to penetrate the insulating sheet; and a surface of the insulating sheet And a step of superimposing an additional substrate sheet and electrically connecting the conductive bump penetrating the insulating sheet and the additional substrate sheet superimposed.

  According to such a method for producing a multilayer printed wiring board, the time required to produce a substrate sheet with conductive bumps, which is necessary when producing the multilayer printed wiring board, can be shortened. For this reason, the time required for manufacturing a multilayer printed wiring board can be shortened.

  In the method for producing a multilayer printed wiring board of the present invention, after transferring the conductive paste onto the substrate sheet, the step of filling the through hole of the screen plate with the conductive paste, the through hole of the screen plate After filling the conductive paste, the conductive paste on the screen plate is pressed onto the through hole of the screen plate by transferring the conductive paste onto the conductive bump of the substrate sheet through the through hole. It is preferable to carry out a series of steps consisting of a step of drying and a step of drying the substrate sheet having the conductive paste transferred onto the conductive bumps once or a plurality of times.

  According to the method for producing a substrate sheet with conductive bumps of the present invention, it is possible to shorten the time required for producing the substrate sheet with conductive bumps.

  Moreover, according to the manufacturing method of the multilayer printed wiring board of this invention, the time required in order to manufacture a multilayer printed wiring board can be shortened.

(A)-(h) is a figure which shows one manufacturing method of the board | substrate sheet | seat with an electroconductive bump by the 1st Embodiment of this invention in order. (A)-(h) is a figure which shows in order the other manufacturing method of the board | substrate sheet | seat with an electroconductive bump by the 1st Embodiment of this invention. (A)-(c) is the squeegee when the conductive paste is filled in the through hole of the screen plate after the previous transfer of the conductive paste to the substrate sheet in the first embodiment of the present invention. Furthermore, it is a figure which shows operation | movement when transferring an electrically conductive paste on the electrically conductive bump of a board | substrate sheet | seat in order. (A)-(c) is a conductive paste further by a squeegee when the conductive paste is not filled in the through hole of the screen plate after the previous transfer of the conductive paste to the substrate sheet in the comparative example. It is a figure which shows operation | movement at the time of making it transfer on the conductive bump of a board | substrate sheet in order. It is a figure which shows the method of manufacturing a multilayer printed wiring board using the board | substrate sheet | seat with an electroconductive bump manufactured by the method as shown in FIG. It is a figure which shows the structure of the multilayer printed wiring board finally obtained. It is a side view which shows the manufacturing apparatus of the board | substrate sheet | seat with an electroconductive bump by the 2nd Embodiment of this invention. It is a side view which expands and shows the squeegee of the manufacturing apparatus of FIG. It is a top view which expands and shows the screen plate of the manufacturing apparatus of FIG. It is sectional drawing which shows the screen plate of FIG. It is a top view which shows the screen plate of the manufacturing apparatus of the board | substrate sheet | seat with an electroconductive bump by the 3rd Embodiment of this invention. It is sectional drawing which shows the screen plate of FIG.

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1A to FIG. 1H are diagrams sequentially illustrating one manufacturing method of a substrate sheet with conductive bumps according to the present embodiment. 2 (a) to 2 (h) are diagrams sequentially illustrating another manufacturing method of the substrate sheet with conductive bumps according to the present embodiment. 3 (a) to 3 (c) are further illustrated by the squeegee when the conductive paste is filled in the through holes of the screen plate after the previous transfer of the conductive paste to the substrate sheet in this embodiment. It is a figure which shows operation | movement when transferring electrically conductive paste on the electrically conductive bump of a substrate sheet in order. On the other hand, FIGS. 4 (a) to 4 (c) show the result of the comparison in the squeegee when the conductive paste is not filled in the through holes of the screen plate after the transfer of the conductive paste to the previous substrate sheet. It is a figure which shows operation | movement when transferring electrically conductive paste on the electrically conductive bump of a substrate sheet in order. FIG. 5 is a diagram showing a method for producing a multilayer printed wiring board using a substrate sheet with conductive bumps produced by the method shown in FIG. 1 and the like, and FIG. 6 is finally obtained. It is a figure which shows the structure of a multilayer printed wiring board.

  Hereinafter, a method for manufacturing a substrate sheet with conductive bumps and a method for manufacturing a multilayer printed wiring board will be sequentially described.

[Method of manufacturing substrate sheet with conductive bumps]
First, the manufacturing method of the board | substrate sheet | seat with an electroconductive bump is demonstrated using FIG.

  First, as shown in FIG. 1A, a substrate sheet 10 made of a metal foil such as a copper foil is placed on a printing surface plate 12, and the printing surface plate 12 is placed at a position directly below the screen plate 20. Move. Here, the screen plate 20 is formed of, for example, a metal mask or a mesh plate, and the screen plate 20 is provided with a plurality of through holes 20a. When the printing surface plate 12 is moved to a position directly below the screen plate 20, the position where the conductive bumps 62 are to be provided on the substrate sheet 10 and the through hole 20 a of the screen plate 20 are aligned. ing.

  A transfer unit 30 is provided in advance above the screen plate 20. The transfer unit 30 includes a squeegee 32 made of an elastic body such as urethane rubber, an arm member 34 connected to the base end portion of the squeegee 32, and a transfer unit main body 36 that supports the arm member 34. The transfer unit main body 36 is movable in the horizontal direction (left-right direction in FIG. 1). Further, the arm member 34 can be extended and contracted downward with respect to the transfer unit main body 36.

  As shown in FIG. 1A, when the printing surface plate 12 is moved to a position directly below the screen plate 20, the conductive paste 60 is placed on the screen plate 20. Here, the initial position is when the transfer unit 30 and the conductive paste 60 are located as shown in FIG.

  Next, as shown in FIGS. 1B and 1C, the conductive paste 60 on the screen plate 20 is pressed into the through hole 20 a of the screen plate 20 by the squeegee 32 of the transfer unit 30. More specifically, with respect to the transfer unit 30, the transfer unit body 36 is moved from the position shown in FIG. 1A to the left in FIG. 1 and the arm member 34 extends downward from the transfer unit body 36. Like that. As a result, the squeegee 32 presses the screen plate 20 downward while moving in the left direction in FIG. 1, and the screen plate 20 at the location pressed by the squeegee 32 contacts the substrate sheet 10. Further, when the squeegee 32 moves in the left direction in FIG. 1, the conductive paste 60 placed on the screen plate 20 is conveyed leftward on the screen plate 20 by the squeegee 32, and the through hole 20 a in the screen plate 20 is also transferred. The conductive paste 60 is pressed toward the through hole 20a by the squeegee 32 at the portion where the conductive paste 60 is provided, and the conductive paste 60 is filled into the through hole 20a. In this way, the conductive paste 60 is transferred onto the substrate sheet 10 below the screen plate 20 through the through hole 20a. At this time, as shown in FIGS. 1B and 1C, the conductive paste 60 filled in the through hole 20a is brought into contact with the screen plate 20 and the substrate sheet 10 at the portion where the through hole 20a is provided. When this is done, a part of it is transferred to the substrate sheet 10, and the rest remains in the through hole 20a.

  Next, the printing surface plate 12 is moved away from a position directly below the screen plate 20, and the printing surface plate 12 is conveyed to a dryer (not shown). Then, the substrate sheet 10 on the printing surface plate 12 is dried by a dryer. As a result, the conductive paste 60 on the substrate sheet 10 is cured by heat and becomes a substantially conical conductive bump 62.

  Further, after the first transfer of the conductive bumps 62 to the substrate sheet 10 is completed, as shown in FIG. 1D, the transfer unit 30 and the conductive paste 60 are placed at the initial positions (the positions of FIG. 1A). Return to).

  Next, as shown in FIGS. 1E and 1F, the conductive paste 60 is filled in the through holes 20 a of the screen plate 20. More specifically, with respect to the transfer unit 30, the transfer unit main body 36 is moved from the position shown in FIG. 1D to the left in FIG. 1 and the arm member 34 extends downward from the transfer unit main body 36. Like that. As a result, when the squeegee 32 moves leftward in FIG. 1, the conductive paste 60 placed on the screen plate 20 is conveyed leftward on the screen plate 20 by the squeegee 32, and penetrates through the screen plate 20. At the place where the hole 20a is provided, the conductive paste 60 is pressed toward the through hole 20a by the squeegee 32, and the conductive paste 60 is filled into the through hole 20a. In this way, in the through hole 20a, in addition to the conductive paste 60 remaining in the through hole 20a at the first transfer of the conductive bump 62 to the substrate sheet 10, a new additional conductive paste is added. 60 will be filled.

  Next, as shown in FIG. 1G, the transfer unit 30 and the conductive paste 60 are returned to the initial positions (positions in FIG. 1A). Further, the printing platen 12 on which the substrate sheet 10 on which the conductive bumps 62 are formed is moved to a position directly below the screen plate 20. At this time, the conductive bumps 62 in the substrate sheet 10 and the through holes 20a of the screen plate 20 are aligned.

  Then, as shown in FIG. 1 (h), the conductive paste 60 on the screen plate 20 is pressed against the through hole 20 a of the screen plate 20 by the squeegee 32 of the transfer unit 30. More specifically, with respect to the transfer unit 30, the transfer unit main body 36 is moved from the position shown in FIG. 1G to the left in FIG. 1 and the arm member 34 extends downward from the transfer unit main body 36. Like that. As a result, the squeegee 32 presses the screen plate 20 downward while moving in the left direction in FIG. 1, and the screen plate 20 at the location pressed by the squeegee 32 contacts the substrate sheet 10. Further, when the squeegee 32 moves in the left direction in FIG. 1, the conductive paste 60 placed on the screen plate 20 is conveyed leftward on the screen plate 20 by the squeegee 32, and the through hole 20a in the screen plate 20 The conductive paste 60 is pressed toward the through hole 20a by the squeegee 32 at the place where the through hole 20a is provided, and the conductive paste 60 filled in the through hole 20a is transferred onto the conductive bumps 62 on the substrate sheet 10. .

  FIGS. 3A to 3C show the case where the conductive paste 60 is filled in the through holes 20a of the screen plate 20 after the previous transfer of the conductive paste 60 to the substrate sheet 10 in the present embodiment. FIG. 4 is a diagram sequentially illustrating operations when the conductive paste 60 is further transferred onto the conductive bumps 62 of the substrate sheet 10 by the squeegee 32.

  As shown in FIG. 3A, in the through hole 20a of the screen plate 20, the conductive paste 60c remaining in the through hole 20a at the time of transferring the conductive paste 60 to the previous substrate sheet 10, and the previous After the transfer of the conductive paste 60 to the substrate sheet 10, two layers of conductive pastes 60b and 60c made of the conductive paste 60b filled in the through holes 20a are filled. Therefore, as shown in FIG. 3B, when the conductive paste 60 a on the screen plate 20 is pressed against the through hole 20 a by the squeegee 32, the conductive paste 60 c is applied to the lower side surface of the conductive bump 62. At the same time, the conductive paste 60 b adheres to the top of the conductive bump 62, and both the conductive pastes 60 b and 60 c are transferred onto the conductive bump 62 as shown in FIG. Thus, the conductive paste 60c remaining in the through hole 20a at the time of the transfer of the conductive paste 60 to the previous substrate sheet 10 and the through hole 20a after the transfer of the conductive paste 60 to the previous substrate sheet 10 are performed. Since both of the conductive paste 60b filled in is transferred onto the conductive bumps 62, the amount of the conductive paste transferred onto the conductive bumps 62 is relatively large.

  Regarding the above-described matters, a case where the conductive paste 60 is not filled in the through hole 20a after the previous transfer of the conductive paste 60 to the substrate sheet 10 will be described as a comparative example. 4 (a) to 4 (c) show the squeegee 32 when the conductive paste 60 is not filled in the through hole 20a after the previous transfer of the conductive paste 60 to the substrate sheet 10 in the comparative example. FIG. 3 is a diagram illustrating operations in order when transferring the conductive paste 60 onto the conductive bumps 62 of the substrate sheet 10.

  As shown in FIG. 4A, the through hole 20a of the screen plate 20 is filled only with the conductive paste 60b remaining in the through hole 20a when the conductive paste 60 was transferred to the substrate sheet 10 last time. ing. Here, as a matter of course, the amount of the conductive paste filled in the through hole 20a in the state shown in FIG. 4A is filled in the through hole 20a in the state shown in FIG. 3A. Less than the amount of conductive paste being applied. And as shown in FIG.4 (b), when the conductive paste 60a on the screen plate 20 is pressed by the through-hole 20a with the squeegee 32, the conductive paste 60b adheres to the top part of the conductive bump 62, As shown in FIG. 4C, the conductive paste 60b is transferred onto the conductive bumps 62. However, the conductive paste does not adhere so much to the lower side surface of the conductive bumps 62, so that FIG. Compared to the state shown, the amount of conductive paste 60 transferred to the conductive bumps 62 is reduced.

  As described above, when the conductive paste 60 is filled in the through hole 20a of the screen plate 20 after the transfer of the conductive paste 60 to the substrate sheet 10, the conductive paste 60 is not filled in the through hole 20a. Thus, the amount of the conductive paste 60 transferred to the conductive bumps 62 on the substrate sheet 10 at the time of transferring the conductive paste 60 to the next substrate sheet 10 increases.

  After the second transfer of the conductive bumps 62 to the substrate sheet 10 is completed, the printing surface plate 12 is moved away from the position directly below the screen plate 20, and the printing surface plate 12 is conveyed to a dryer (not shown). To do. Then, the substrate sheet 10 on the printing surface plate 12 is dried by a dryer. As a result, the conductive paste 60 on the substrate sheet 10 is cured by heat and integrated with the conductive bumps 62 that have already been formed on the substrate sheet 10, thereby increasing the conductive bumps 62.

  In the manufacturing method of the substrate sheet 10 with the conductive bumps 62 of the present embodiment, as shown in FIGS. 1D to 1F, a step of filling the through holes 20a of the screen plate 20 with the conductive paste 60, A process of transferring the conductive paste 60 onto the conductive bumps 62 of the substrate sheet 10 after filling the through holes 20a of the screen plate 20 with the conductive paste 60, as shown in FIGS. The process of drying the substrate sheet 10 having the conductive paste 60 transferred onto the conductive bumps 62 is repeated once or a plurality of times. In this way, the substrate sheet 10 on which the conductive bumps 62 having a desired height are formed is obtained.

[Manufacturing method of multilayer printed wiring board]
Next, a method for manufacturing a multilayer printed wiring board using the substrate sheet 10 with the conductive bumps 62 manufactured by the method shown in FIG. 1 will be described with reference to FIGS.

  As shown in FIG. 5, in a state where the substrate sheet 10 with the conductive bumps 62 is placed on the printing surface plate 12, the surface of the substrate sheet 10 with the conductive bumps 62 on which the conductive bumps 62 are formed is formed. The insulating sheet 74 is placed, and the cushioning material 76 is placed on the insulating sheet 74. Then, the conductive bump 62 penetrates the insulating sheet 74 by sandwiching and heating the printed surface plate 12, the substrate sheet 10 with the conductive bump 62, the insulating sheet 74, and the buffer material 76. More specifically, the laminated body of the printing surface plate 12, the substrate sheet 10 with the conductive bumps 62, the insulating sheet 74, and the buffer material 76 is conveyed between a pair of heating rollers 70 and 72 that rotate continuously. As a result, the laminate is sandwiched from above and below and heated. In this way, the back surface of the insulating sheet 74 (the lower surface in FIG. 5) is pressed against the conductive bumps 62 of the substrate sheet 10, and the conductive bumps 62 are broken by breaking the insulating sheet 74. To penetrate.

  Thereafter, the buffer material 76 is removed from the laminate of the printing surface plate 12, the substrate sheet 10 with the conductive bumps 62, the insulating sheet 74, and the buffer material 76. Then, the additional substrate sheet 11 is superposed on the insulating sheet 74, and the conductive bumps 62 penetrating the insulating sheet 74 and the additional substrate sheet 11 are electrically connected. As a result, a multilayer printed wiring board 80 as shown in FIG. 6 is obtained.

  As described above, according to the method for manufacturing the substrate sheet 10 with the conductive bumps 62 of the present embodiment, the first conductive paste 60 is transferred onto the substrate sheet 10 and then applied to the substrate sheet 10 for the second and subsequent times. In the transfer of the conductive paste 60, the conductive paste 60 is filled in the through holes 20 a of the screen plate 20 in advance, and then the conductive paste 60 is transferred to the substrate sheet 10 using the screen plate 20. Therefore, a larger amount of the conductive paste 60 is applied to the substrate sheet 10 than when the conductive paste 60 is transferred to the substrate sheet 10 without filling the through holes 20a of the screen plate 20 with the conductive paste 60. The larger conductive bumps 62 can be formed on the substrate sheet 10 by one screen printing. As a result, the position where the conductive bumps 62 are to be formed on the substrate sheet 10 and the through holes 20 a of the screen plate 20 are aligned, the conductive paste 60 is transferred to the substrate sheet 10, and the substrate sheet 10 is electrically conductive. The number of times of performing a series of steps including drying of the substrate sheet 10 after transferring the conductive paste 60 can be reduced. For this reason, the time required for manufacturing the board | substrate sheet | seat 10 with the conductive bump 62 can be shortened.

  In the method for manufacturing the substrate sheet 10 with the conductive bumps 62 according to the present embodiment, as described above, the conductive paste 60 is transferred to the through hole 20a of the screen plate 20 after the conductive paste 60 is transferred onto the substrate sheet 10. And filling the through-hole 20a of the screen plate 20 with the conductive paste 60, and then pressing the conductive paste 60 on the screen plate 20 against the through-hole 20a of the screen plate 20 to thereby form the through-hole 20a. A series of steps consisting of a step of transferring the conductive paste 60 onto the conductive bumps 62 of the substrate sheet 10 and a step of drying the substrate sheet 10 onto which the conductive paste 60 has been transferred onto the conductive bumps 62. Is to be performed once or multiple times. As described above, according to the method for manufacturing the substrate sheet 10 with the conductive bumps 62 of the present embodiment, the number of times such a series of steps is performed is determined in the conductive paste 60 in the through hole 20a of the screen plate 20. Compared with the case where the conductive paste 60 is transferred onto the substrate sheet 10 without filling the substrate sheet 10, the amount of the conductive paste 60 can be reduced. Specifically, when the conductive paste 60 is transferred onto the substrate sheet 10 without filling the through holes 20a of the screen plate 20 with the conductive paste 60, the conductivity on the substrate sheet 10 is four times in total. When the paste 60 is transferred, the conductive paste 60 is transferred onto the substrate sheet 10 after filling the through holes 20a of the screen plate 20 with the conductive paste 60. The number of transfers of the conductive paste 60 can be reduced to three.

  In the method for manufacturing the substrate sheet 10 with the conductive bumps 62 of the present embodiment, when the conductive paste 60 is transferred onto the substrate sheet 10, the conductive paste on the screen plate 20 by the pressing member such as the squeegee 32. 60 is pressed into the through hole 20a of the screen plate 20, and when the conductive paste 60 is filled into the through hole 20a of the screen plate 20, the conductive paste 60 is filled into the through hole 20a of the screen plate 20 with this pressing member. It is supposed to be.

  Further, according to the method for manufacturing the multilayer printed wiring board 80 of the present embodiment, the time required for manufacturing the substrate sheet 10 with the conductive bumps 62 required when manufacturing the multilayer printed wiring board 80 is reduced. It can be shortened. For this reason, the time required for manufacturing the multilayer printed wiring board 80 which is the final product can be shortened.

  In addition, the manufacturing method of the board | substrate sheet | seat 10 with the conductive bump 62 in this Embodiment is not limited to the above examples, A various change can be added.

  For example, the transfer unit for transferring the conductive paste 60 on the screen plate 20 to the substrate sheet 10 is not limited to the one having only the squeegee as shown in FIG. 1, and both the squeegee and the scraper are used. It can also be provided. 2A to 2H are views sequentially illustrating a method of manufacturing a substrate sheet with conductive bumps using a transfer unit including both a squeegee and a scraper.

  As shown in FIG. 2A, a transfer unit 40 is provided in advance above the screen plate 20. The transfer unit 40 includes a squeegee 42, an arm member 44 connected to the base end portion of the squeegee 42, a scraper 46, an arm member 48 connected to the base end portion of the scraper 46, an arm member 44 and an arm member 48. And a transfer unit main body 49 that supports both of them. The transfer unit main body 49 is movable in the horizontal direction (left and right direction in FIG. 2). In addition, the arm member 44 and the arm member 48 can be extended and contracted downward independently of each other with respect to the transfer unit main body 49. The squeegee 42 has substantially the same configuration as the squeegee 32 shown in FIG. As the scraper 46, for example, a squeegee, a sword squeegee, or a square squeegee using an elastic body such as urethane rubber is used. Here, the flat squeegee has a rectangular cross section and the screen plate 20 is in contact with the surface portion. The sword squeegee has a tapered cross section and the screen plate 20 has a corner portion in contact with the flat squeegee. The square squeegee has a rhombus shape in cross section and a corner portion is in contact with the screen plate 20, and these have the conductive paste 60 applied to the through hole 20 a of the screen plate 20. The shape is easy to fill. As the scraper 46, a flat squeegee core portion reinforced with a highly rigid material, a metal metal squeegee, or the like can also be used.

  A method of manufacturing the substrate sheet 10 with the conductive bumps 62 using the transfer unit 40 as shown in FIG. 2A will be described in order with reference to FIGS.

  First, as shown in FIG. 2A, the substrate sheet 10 is placed on the printing surface plate 12, and the printing surface plate 12 is moved to a position directly below the screen plate 20. At this time, the position of the conductive bump 62 on the substrate sheet 10 and the position of the through hole 20a of the screen plate 20 are aligned. A transfer unit 40 is provided in advance above the screen plate 20. At this time, the arm member 44 extends downward from the transfer unit main body 49 so that the squeegee 42 contacts the upper surface of the screen plate 20, and the scraper 46 retracts upward from the upper surface of the screen plate 20. 48 is in a contracted state.

  As shown in FIG. 2A, the conductive paste 60 is placed on the screen plate 20 when the printing surface plate 12 is moved to a position directly below the screen plate 20. Here, the initial position is when the transfer unit 40 and the conductive paste 60 are located as shown in FIG.

  Next, as shown in FIGS. 2B and 2C, the conductive paste 60 on the screen plate 20 is pressed into the through hole 20 a of the screen plate 20 by the squeegee 42 of the transfer unit 40. More specifically, with respect to the transfer unit 40, the transfer unit main body 49 is moved in the left direction in FIG. 2 from the position shown in FIG. 2A, and the arm member 44 extends downward from the transfer unit main body 49. Like that. Thereby, the squeegee 42 presses the screen plate 20 downward while moving in the left direction in FIG. 2, and the screen plate 20 at the location pressed by the squeegee 42 contacts the substrate sheet 10. Further, when the squeegee 42 moves leftward in FIG. 2, the conductive paste 60 placed on the screen plate 20 is conveyed leftward on the screen plate 20 by the squeegee 42, and the through hole 20 a in the screen plate 20 is also transferred. The conductive paste 60 is pressed toward the through hole 20a by the squeegee 42 at the place where the conductive paste 60 is provided, and the conductive paste 60 is filled into the through hole 20a. In this way, the conductive paste 60 is transferred onto the substrate sheet 10 below the screen plate 20 through the through hole 20a. At this time, as shown in FIGS. 2B and 2C, the conductive paste 60 filled in the through hole 20a is brought into contact with the screen plate 20 and the substrate sheet 10 at the place where the through hole 20a is provided. When this is done, a part of it is transferred to the substrate sheet 10, and the rest remains in the through hole 20a.

  Next, the printing surface plate 12 is moved away from a position directly below the screen plate 20, and the printing surface plate 12 is conveyed to a dryer (not shown). Then, the substrate sheet 10 on the printing surface plate 12 is dried by a dryer. As a result, the conductive paste 60 on the substrate sheet 10 is cured by heat and becomes a substantially conical conductive bump 62.

  Further, after the first transfer of the conductive bumps 62 to the substrate sheet 10 is completed, as shown in FIGS. 2D, 2E and 2F, the transfer unit 40 is as shown in FIG. When returning from the position to the initial position (position shown in FIG. 2A), the conductive paste 60 is filled into the through hole 20 a of the screen plate 20. More specifically, in the transfer unit 40, the arm member 44 is contracted so that the squeegee 42 is retracted upward from the upper surface of the screen plate 20, and the arm member 48 is moved so that the scraper 46 contacts the upper surface of the screen plate 20. The portion 49 extends downward. Then, the transfer unit main body 49 is moved to the right in FIG. 2 from the position shown in FIG. 2D, and the arm member 48 extends further downward from the transfer unit main body 49. As a result, when the scraper 46 moves to the right in FIG. 2, the conductive paste 60 placed on the screen plate 20 is conveyed to the right on the screen plate 20 by the scraper 46, and penetrates through the screen plate 20. At the place where the hole 20a is provided, the conductive paste 60 is pressed toward the through hole 20a by the scraper 46, and the conductive paste 60 is filled into the through hole 20a. In this way, in the through hole 20a, in addition to the conductive paste 60 remaining in the through hole 20a at the first transfer of the conductive bump 62 to the substrate sheet 10, a new additional conductive paste is added. 60 will be filled.

  Next, as shown in FIG. 2G, the transfer unit 40 and the conductive paste 60 are returned to the initial positions (positions in FIG. 2A). Further, the printing platen 12 on which the substrate sheet 10 on which the conductive bumps 62 are formed is moved to a position directly below the screen plate 20. At this time, the conductive bumps 62 in the substrate sheet 10 and the through holes 20a of the screen plate 20 are aligned. In the transfer unit 40, the arm member 44 extends downward from the transfer unit main body 49 so that the squeegee 42 contacts the upper surface of the screen plate 20, and the scraper 46 retracts upward from the upper surface of the screen plate 20. 48 to shrink.

  Then, as shown in FIG. 2 (h), the conductive paste 60 on the screen plate 20 is pressed against the through hole 20 a of the screen plate 20 by the squeegee 42 of the transfer unit 40. More specifically, with respect to the transfer unit 40, the transfer unit main body 49 is moved to the left in FIG. 2 from the position shown in FIG. 2G, and the arm member 44 extends downward from the transfer unit main body 49. Like that. Thereby, the squeegee 42 presses the screen plate 20 downward while moving in the left direction in FIG. 2, and the screen plate 20 at the location pressed by the squeegee 42 contacts the substrate sheet 10. Further, when the squeegee 42 moves leftward in FIG. 2, the conductive paste 60 placed on the screen plate 20 is conveyed leftward on the screen plate 20 by the squeegee 42, and the through hole 20 a in the screen plate 20 is also transferred. The conductive paste 60 is pressed toward the through hole 20a by the squeegee 42 at the location where the squeegee is provided, and the conductive paste 60 filled in the through hole 20a is transferred onto the conductive bumps 62 on the substrate sheet 10. .

  Here, when the conductive paste 60 is filled in the through hole 20a of the screen plate 20 after the transfer of the conductive paste 60 to the substrate sheet 10, the conductive paste 60 is not filled in the through hole 20a. When the conductive paste 60 is transferred to the next substrate sheet 10, the amount of the conductive paste 60 transferred to the conductive bumps 62 on the substrate sheet 10 increases.

  After the second transfer of the conductive bumps 62 to the substrate sheet 10 is completed, the printing surface plate 12 is moved away from the position directly below the screen plate 20, and the printing surface plate 12 is conveyed to a dryer (not shown). To do. Then, the substrate sheet 10 on the printing surface plate 12 is dried by a dryer. As a result, the conductive paste 60 on the substrate sheet 10 is cured by heat and integrated with the conductive bumps 62 that have already been formed on the substrate sheet 10, thereby increasing the conductive bumps 62.

  In the manufacturing method of the substrate sheet 10 with the conductive bumps 62 according to the modification, the process of filling the through holes 20a of the screen plate 20 with the conductive paste 60 as shown in FIGS. Steps of transferring the conductive paste 60 onto the conductive bumps 62 of the substrate sheet 10 after filling the through holes 20a of the screen plate 20 with the conductive paste 60 as shown in 2 (g) to (h), and conductive The step of drying the substrate sheet 10 having the conductive paste 60 transferred onto the conductive bumps 62 is repeated once or a plurality of times. In this way, the substrate sheet 10 on which the conductive bumps 62 having a desired height are formed is obtained.

  As described above, according to the method of manufacturing the substrate sheet 10 with the conductive bumps 62 as shown in FIG. 2, the transfer unit 40 having the squeegee 42 and the scraper 46 is arranged in one direction on the screen plate 20 (left direction in FIG. 2). ), The conductive paste 60 is transferred onto the substrate sheet 10 by the squeegee 42, and the transfer unit 40 is in the other direction opposite to the one direction on the screen plate 20 (right direction in FIG. 2). When moving to, the scraper 46 fills the through hole 20a of the screen plate 20 with the conductive paste 60. In this case, when the transfer unit 40 having the squeegee 42 and the scraper 46 moves in one direction from the initial position (the position shown in FIG. 2A), the conductive paste 60 is transferred onto the substrate sheet 10, and thereafter Since the conductive paste 60 can be filled in the through hole 20a of the screen plate 20 when moving in the opposite direction to the initial position and returning to the initial position, the transfer unit 40 can be reciprocated once on the substrate sheet 10. The conductive paste 60 can be transferred to and the through-hole 20a of the screen plate 20 can be filled with the conductive paste 60. For this reason, the time required to manufacture the board | substrate sheet | seat 10 with the conductive bump 62 can be shortened further.

  Further, in another modification of the method for manufacturing the substrate sheet 10 with the conductive bumps 62 in the present embodiment, before the transfer of the conductive paste 60 to the substrate sheet 10 for the first time, the through holes 20a of the screen plate 20 are provided. The conductive paste 60 may be filled in advance. However, the manufacturing method of the substrate sheet 10 with the conductive bumps 62 in the present embodiment is not limited to such a method, and the screen before the transfer of the conductive paste 60 to the substrate sheet 10 is performed for the first time. The through-hole 20a of the plate 20 may not be filled with the conductive paste 60 in advance.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side view showing an apparatus for manufacturing a substrate sheet with conductive bumps according to the second embodiment, and FIG. 8 is an enlarged side view showing the squeegee of the apparatus shown in FIG. FIG. 9 is an enlarged plan view showing a screen plate of the manufacturing apparatus of FIG. 7, and FIG. 10 is a cross-sectional view showing the screen plate of FIG.

  In the method for manufacturing a substrate sheet with conductive bumps according to the present invention, as described in the first embodiment, the screen plate 20 is moved in a state where the printing surface plate 12 is withdrawn from the position directly below the screen plate 20. The conductive paste 60 is filled in the through hole 20a. That is, the screen plate 20 is pressed downward by the squeegee 32 in a state where there is no structure for supporting the screen plate 20 from below. In this case, most of the pushing pressure applied to the squeegee 32 from the arm member 34 of the transfer unit 30 is used as a force for pushing the screen plate 20 downward. Therefore, when the pressing pressure applied from the arm member 34 of the transfer unit 30 to the squeegee 32 is the same during transfer and filling, the squeegee 32 is more electrically conductive during filling than during transfer. It is thought that the force which pushes 60 down becomes small. Therefore, in order to properly fill the through hole 20a of the screen plate 20 with the conductive paste 60 at the time of filling, the pressing pressure applied to the squeegee 32 from the arm member 34 of the transfer unit 30 is set to a predetermined magnitude (for filling). Must be larger than the lower limit of the indentation pressure. Similarly, at the time of filling, in order to prevent the screen plate 20 from being pushed down too much, it is necessary to make the tension applied to the screen plate 20 larger than a predetermined size (tension lower limit value for filling). There is.

  On the other hand, at the time of transfer, when the pushing pressure applied to the squeegee 32 from the arm member 34 of the transfer unit 30 becomes excessively large, the squeegee 32 is pushed deep into the through hole 20a. In this case, it is conceivable that the conductive paste 60 filled in the through hole 20a is scraped off by the squeegee 32. In this case, the amount of the conductive paste 60 transferred onto the substrate sheet 10 is reduced by the scraped conductive paste 60. In addition, when the tip of the squeegee 32 is pushed deeply into the through hole 20a, the conductive paste 62 transferred onto the conductive bumps 62 and the substrate sheet 10 may spread over a wide area, that is, printing may be blurred. If printing is blurred in this manner, the cross-sectional area of the conductive bump 62 obtained is increased, and the height of the conductive bump 62 obtained by one printing is decreased, which is not preferable. Furthermore, if the tip of the squeegee 32 is pushed deeply into the through hole 20a, the tip of the conductive bump 62 already formed on the substrate sheet 10 may be scraped off by the squeegee 32. Therefore, in order to appropriately transfer the conductive paste 60 in the through hole 20a of the screen plate 20 onto the substrate sheet 10 at the time of transfer, a pressing pressure applied to the squeegee 32 from the arm member 34 of the transfer unit 30 is set to a predetermined value. It is necessary to make it smaller than the size (indentation pressure upper limit value for transfer). Further, at the time of transfer, in order to sufficiently bring the screen plate 20 into close contact with the substrate sheet 10, it is necessary to make the tension applied to the screen plate 20 smaller than a predetermined size (tension upper limit value for transfer). is there.

The inventors of the present invention, through repeated experiments, satisfy both the condition that it is larger than the indentation pressure lower limit value for the above filling and the condition that it is smaller than the indentation pressure upper limit value for the above transfer. The range of the pushing pressure of the squeegee 32 was found. Specifically, by pushing the squeegee 32 downward so that the value obtained by dividing the pushing pressure of the squeegee 32 by the squeegee width s ₈ (described later) becomes a constant value in the range of 0.3 to 0.9 N / mm. The through hole 20a of the screen plate 20 is sufficiently filled with the conductive paste 60 at the time of filling, and the conductive paste 60 is appropriately applied to the substrate sheet 10 without scraping off the conductive paste 60 in the through hole 20a at the time of transfer. It has been found that it can be transferred onto.
In addition, the present inventors have conducted extensive experiments to satisfy both the condition that the tension lower limit value for the filling is larger than the tension lower limit value for the transfer and the condition that the tension is smaller than the tension upper limit value for the transfer. The range of tension of the plate 20 was found. Specifically, the screen plate 20 is stretched so that the value obtained by dividing the tension of the screen plate 20 by the width s ₃ (described later) of the screen plate 20 becomes a constant value in the range of 1.4 to 3.6 N / mm. By doing so, the conductive paste 60 is sufficiently filled in the through hole 20a of the screen plate 20 at the time of filling, and the conductive paste 60 is appropriately removed without scraping off the conductive paste 60 in the through hole 20a at the time of transfer. It was found that it can be transferred onto the substrate sheet 10.
Hereinafter, the manufacturing apparatus 15 for setting the pushing pressure of the squeegee 32 and the tension of the screen plate 20 within such a range will be described.

The manufacturing apparatus 15 will be described with reference to FIGS. In the manufacturing apparatus 15 shown in FIGS. 7 to 10, the same components as those used in the manufacturing method shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 7, the manufacturing apparatus 15 is disposed above the printing surface plate 12 on which the substrate sheet 10 made of metal foil such as copper foil is placed, and the conductive paste 60 (paste). And a squeegee (pressing member) 32 that travels on the screen plate 20 while being pushed downward with a predetermined pushing pressure. Further, as shown in FIG. 7, the printing plate 12 is printed platen drive unit 13 of the movably mounted in the horizontal direction indicated by the arrow D _1. Therefore, when the conductive paste 60 is filled or when the conductive paste 60 printed on the substrate sheet 10 is dried, the substrate sheet 10 and the printing platen 12 are moved from below the screen plate 20 to FIG. It can be moved (retracted) in the left direction shown.

  As shown in FIG. 7, the manufacturing apparatus 15 further includes a temperature adjustment mechanism 16 that covers the screen plate 20 from above and adjusts the temperature and humidity in the vicinity of the screen plate 20. The temperature adjustment mechanism 16 includes a partition wall 16a that covers the screen plate 20 from above, and an adjustment unit (not shown) that is provided inside the partition wall 16a and adjusts the temperature and humidity inside the partition wall 16a. . For this reason, the temperature and humidity around the conductive paste 60 at the time of filling or transferring the conductive paste 60 can always be kept constant, whereby the viscosity of the conductive paste 60 at the time of filling or transferring is always kept constant. Can be kept constant. Although not shown, the partition wall 16a of the temperature adjusting mechanism 16 has an opening through which the substrate sheet 10 and the printing surface plate 12 pass when the printing surface plate driving unit 13 is retracted from below the screen plate 20. .

Transfer Unit Next, the transfer unit 30 will be described in more detail with reference to FIGS. The transfer unit main body 36 of the transfer unit 30 is movable along the squeegee rail 38 in the horizontal direction indicated by the arrow D ₂ , and the squeegee 32 travels on the screen plate 20 by the transfer unit main body 36. Can be made. The speed (travel speed) at which the squeegee 32 travels on the screen plate 20 is in the range of, for example, 5 to 150 mm / s, and the travel speed is appropriately adjusted depending on the case within this range.

The arm member 34, as described above, and can stretch by a predetermined length in the vertical direction indicated by the arrow D ₄ to the transfer unit body 36. Therefore, at the time of filling or transferring, the squeegee 32 is pushed downward at a constant pushing pressure F ₁ (see FIGS. 7 and 8) by extending the arm member 34 downward from the transfer unit main body 36 by a certain length. be able to. The pushing pressure F ₁ is identical in size with time of filling and during the transfer. Specifically, the arm member 34 is set such that a value obtained by dividing the pushing pressure F ₁ of the squeegee 32 by the squeegee width s ₈ (see FIG. 9) becomes a constant value within a range of 0.3 to 0.9 N / mm. Is extended downward from the transfer unit main body 36. Further, after completion of the filling or transfer, the squeegee 32 can be separated from the screen plate 20 by shrinking the arm member 34 upward. The pushing pressure F ₁ is pushed when the lower end 32 b of the squeegee 32 is not in contact with the screen plate 20, that is, when only the force that supports the weight of the squeegee 32 is acting between the arm member 34 and the squeegee 32. is defined as the pressure F ₁ becomes zero.

As shown in FIG. 8, a squeegee angle adjusting unit 33 that adjusts an angle θ _{1 of the} squeegee 32 with respect to the screen plate 20 is interposed between the squeegee 32 and the arm member 34. The squeegee angle adjusting unit 33 is for rotatably supported in the direction indicated by the squeegee 32 by the arrow D _3, Therefore, it is appropriately adjusted depending on the case the angle theta ₁ of the squeegee 32 with respect to the screen plate 20 Can do.

Screen Plate Next, the screen plate 20 and the peripheral mechanism of the screen plate 20 will be described in more detail with reference to FIGS. FIG. 9 is a plan view showing the screen plate 20 and the squeegee 32 as viewed from above. As shown in FIG. 9, the screen plate 20 has, for example, a rectangular planar shape, its width _{s 3} has become within a range of, for example 300 to 800 mm, the length _{s 2,} for example 450 It is in the range of 950 mm. The thickness of the screen plate 20 (= depth of the through hole 20a) s ₁ (see FIG. 8) is, for example, 150 μm. The diameter _{s 10} of the through hole 20a is generally has a range of 50 to 300 [mu] m, for example, a 150 [mu] m.

Next, the mechanism around the screen plate 20 will be described with reference to FIGS. As shown in FIGS. 9 and 10, the screen plate 20 is held in a horizontally stretched state by a frame 27 surrounding the screen plate 20. That, is stretched at a constant tension F _2. Specifically, the screen plate 20 has a frame so that the value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 becomes a constant value in the range of 1.4 to 3.6 N / mm. 27.

Method for Manufacturing Substrate Sheet with Conductive Bump Next, a method for manufacturing the substrate sheet with conductive bump 10 using the manufacturing apparatus 15 having such a configuration will be described. In addition, the manufacturing method of the substrate sheet 10 with conductive bumps in the present embodiment is such that the pressing pressure F ₁ of the squeegee 32, the tension F ₂ of the screen plate 20, and the temperature and humidity around the conductive paste 60 are constant within a predetermined range. The only difference is that the values are set, and the other points are substantially the same as the manufacturing method in the first embodiment shown in FIG. Therefore, also in the present embodiment, the manufacturing method will be described with reference to FIG. 1 and detailed description of the same steps as those in the first embodiment will be omitted.

First, as shown in FIG. 1A, a substrate sheet 10 made of a metal foil such as a copper foil is placed on a printing surface plate 12, and the printing surface plate 12 is placed at a position directly below the screen plate 20. Move. Next, the conductive paste 60 is placed on the screen plate 20. At this time, the temperature and humidity around the conductive paste 60 placed on the screen plate 20 are within a certain range, for example, the temperature is within a range of 23 ± 3 ° C. and the humidity is within a range of 50 ± 5%. The temperature adjustment mechanism 16 is driven. The screen plate 20 has a constant value within a range of 1.4 to 3.6 N / mm, for example, 3.0 N / mm, obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20. It is set to the frame 27 so that it may become. At this time, a distance s ₉ (see FIG. 10) between the one end 20b of the screen plate 20 and the substrate sheet 10 is, for example, 1.5 mm.

Next, as shown in FIGS. 1B and 1C, the conductive paste 60 on the screen plate 20 is pressed into the through hole 20 a of the screen plate 20 by the squeegee 32 of the transfer unit 30. That is, the arm member 34 is extended downward from the transfer unit main body 36. As a result, the squeegee 32 is pushed downward with a force such that a value obtained by dividing the pushing pressure F ₁ of the squeegee 32 by the width s ₈ of the squeegee becomes 0.5 N / mm. In this state, the transfer unit main body 36 is moved leftward in FIG. As a result, the conductive paste 60 is transferred onto the substrate sheet 10 below the screen plate 20 through the through hole 20a.

  Next, the printing surface plate 12 is moved away from a position directly below the screen plate 20, and the printing surface plate 12 is conveyed to a dryer (not shown). Then, the substrate sheet 10 on the printing surface plate 12 is dried by a dryer. As a result, the conductive paste 60 on the substrate sheet 10 is cured by heat and becomes a substantially conical conductive bump 62.

  Further, after the first transfer of the conductive bumps 62 to the substrate sheet 10 is completed, as shown in FIG. 1D, the transfer unit 30 and the conductive paste 60 are placed at the initial positions (the positions of FIG. 1A). Return to).

Next, as shown in FIGS. 1E and 1F, the conductive paste 60 is filled in the through holes 20 a of the screen plate 20. At this time, the value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 is 3.0 N / mm as in the above-described transfer.

First, the arm member 34 is extended downward from the transfer unit main body 36. Thus, similarly to the time of transfer, divided by the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 with a force such that 0.5 N / mm, squeegee 32 is pushed downward. In this state, the transfer unit main body 36 is moved leftward in FIG. As a result, in addition to the conductive paste 60 remaining in the through hole 20a when the first conductive bump 62 is transferred to the substrate sheet 10 for the first time, the additional conductive paste 60 is newly filled in the through hole 20a. Is done.

  Next, as shown in FIG. 1G, the transfer unit 30 and the conductive paste 60 are returned to the initial positions (positions in FIG. 1A). Further, the printing platen 12 on which the substrate sheet 10 on which the conductive bumps 62 are formed is moved to a position directly below the screen plate 20. At this time, alignment of the conductive bumps 62 on the substrate sheet 10 and the through holes 20a of the screen plate 20 is performed using, for example, a CCD camera.

Then, as shown in FIG. 1 (h), the conductive paste 60 on the screen plate 20 is pressed against the through hole 20 a of the screen plate 20 by the squeegee 32 of the transfer unit 30. At this time, the value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 is 3.0 N / mm as in the above-described transfer. Similarly to the time of filling, divided by the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 with a force such that 0.5 N / mm, squeegee 32 is pushed downward. In this state, the transfer unit main body 36 is moved leftward in FIG. As a result, the conductive paste 60 filled in the through holes 20a is transferred onto the conductive bumps 62 on the substrate sheet 10.

During this time, according to this embodiment, as described above, with such force divided by the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 is 0.5 N / mm, squeegee 32 downward It is pushed in. This value of 0.5 N / mm is greater than the value obtained by dividing the width s ₈ of the squeegee pressure lower limit indentation for the filling, and divided by the pushing pressure upper limit value for the transfer width s ₈ of the squeegee It is smaller than the value. Further, the screen plate 20 is set on the frame 27 so that a value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 is 3.0 N / mm. This value of 3.0 N / mm is larger than the value obtained by dividing the tension lower limit value for filling by the width s ₃ of the screen plate 20, and the tension upper limit value for transfer is set to the width s _{3 of the} screen plate 20. It is smaller than the value divided by. Accordingly, the conductive paste 60 is sufficiently filled in the through hole 20a of the screen plate 20 at the time of filling, and the conductive paste 60 is appropriately removed without scraping off the conductive paste 60 in the through hole 20a at the time of transfer. It can be transferred onto the substrate sheet 10.

Further, according to the present embodiment, the temperature adjustment mechanism 16 is driven so that the temperature and humidity around the conductive paste 60 placed on the screen plate 20 are constant. For this reason, the viscosity of the conductive paste 60 at the time of filling or transferring can always be kept constant. In this way, the combination of keeping the viscosity of the conductive paste 60 constant at all times and keeping the indentation pressure F ₁ and the tension F ₂ at the time of filling and transfer within appropriate ranges as described above. It is possible to accurately control the amount of the conductive paste 60 filled in the through hole 20a and the amount of the conductive paste 60 transferred onto the substrate sheet 10 during transfer.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a plan view showing a screen plate according to the third embodiment of the present invention, and FIG. 12 is a cross-sectional view showing the screen plate of FIG.

  The third embodiment shown in FIGS. 11 and 12 differs only in that the screen plate is stretched by a pair of stretchers, and the other configurations are the same as those of the second embodiment shown in FIGS. This is substantially the same as the embodiment. In the third embodiment shown in FIGS. 11 and 12, the same parts as those in the second embodiment shown in FIGS.

Referring to the screen plate 11 and 12, will be described mechanism around the screen plate 20 and the screen plate 20 in this embodiment. As shown in FIG. 12, the screen plate 20 is stretched with a predetermined tension F ₂ by a pair of stretching tools 21. The pair of tensioning tools 21 are arranged at predetermined intervals, and each tensioning tool 21 includes a fixture 24 that holds the screen plate 20 and a space between the fixture 24 and the screen plate 20. And a reinforcing plate 22 interposed therebetween. The reinforcing plate 22 is interposed between the fixture 24 and the screen plate 20 in order to prevent the mounting hole 23 (see FIG. 11) of the screen plate 20 for fixing the screen plate 20 from being deformed. For example, the reinforcing plate 22 may be made of a metal plate made of copper or aluminum, or may be made of a resin plate made of resin.

In the reinforcing plate 22 described above, the width _{s 5} is a 40mm example, the length _{s 4} is made, for example, 550 mm. The thickness _{s 6} of the reinforcing plate 22 has a larger becomes and, for example, 0.2mm than the thickness _{s 1} of the screen plate 20. However, the dimensions of the reinforcing plate 22 are not limited to these values, and the dimensions of the reinforcing plate 22 are appropriately set according to the material of the screen plate 20 and the like. For example, the thickness s ₆ of the reinforcing plate 22 may be substantially the same as the thickness s ₁ of the screen plate 20.

As shown in FIG. 12, a tensioning tool horizontal drive unit 25 that is extendable in the horizontal direction indicated by an arrow D ₆ is attached to the tensioning tool 21 arranged on the right side of the pair of tensioning tools 21. . For this reason, the tension F ₂ applied to the screen plate 20 can be adjusted by extending and contracting the tension tool horizontal drive unit 25. In this case, the tension tool horizontal drive unit 25 has a value obtained by dividing the tension F ₂ applied to the screen plate 20 by the width s ₃ of the screen plate 20 within a range of 1.4 to 3.6 N / mm. Adjusted. For this reason, the conductive paste 60 is sufficiently filled in the through hole 20a of the screen plate 20 at the time of filling, and the conductive paste 60 is appropriately applied to the substrate without scraping off the conductive paste 60 in the through hole 20a at the time of transfer. It can be transferred onto the sheet 10.

By the way, when repeatedly printing using a screen plate 20, it is conceivable that the tension F ₂ of the screen plate 20 gradually decreases. Even in such a case, according to the present embodiment, as described above, the tension F ₂ applied to the screen plate 20 can be adjusted by expanding and contracting the tension tool horizontal driving unit 25. it can. For this reason, even when the tension F ₂ of the screen plate 20 gradually decreases and as a result, the tension F ₂ of the screen plate 20 is out of the range of 1.4 to 3.6 N / mm, the tensioning tool by appropriately stretch the horizontal driving unit 25, can be in the range of the tension _{F 2} again 1.4~3.6N / mm of screen plate 20.

Further, as shown in FIG. 12, the extension tool horizontal driving unit 25, is connected to the extension tool vertical drive unit 26 of movable along the vertical direction extending extension tool rail 28 indicated by the arrow D ₅ Yes. Therefore, by moving the extension tool vertical drive unit 26 in the vertical direction, it is possible to adjust the distance s ₉ between the one end 20b and the substrate sheet 10 of the screen plate 20. In this case, the extension tool vertical drive unit 26, the distance _{s 9} between the one end 20b and the substrate sheet 10 of the screen plate 20 is controlled to be in the range of 0.5 to 10 mm. Within this range, the distance s ₉ described above is adjusted appropriately depending on the case.

For example, in the step shown in FIG. 1 (b) (c), as the squeegee 32 moves to the left, so that the distance s ₉ between the one end 20b and the substrate sheet 10 of the screen plate 20 is increased, the extension tool The vertical drive unit 26 is controlled. Accordingly, the degree of plate separation in each through hole 20a can be made constant regardless of the position of the through hole 20a. As a result, when the screen plate 20 is separated from the substrate sheet 10, The amount of the conductive paste 60 transferred to can be made almost constant regardless of the position.

In each of the above embodiments, the traveling speed of the squeegee 32 at the time of transfer and the traveling speed of the squeegee 32 at the time of filling may be the same or different. For example, the traveling speed of the squeegee 32 at the time of filling may be smaller than the traveling speed of the squeegee 32 at the time of transfer. As a result, more conductive paste 60 can be filled into the through holes 20a of the screen plate 20 during filling.
In the first transfer, the conductive bumps 62 are not formed on the screen plate 20. For this reason, at the time of the first transfer, the conductive paste 60 in the through hole 20a is transferred to the screen plate 20 as compared with the case where the conductive paste 60 is transferred onto the conductive bumps 62 (at the time of the second and subsequent transfers). It can be considered that it takes a long time to firmly adhere to the skin. For this reason, preferably, the squeegee 32 is driven by the transfer unit main body 36 of the transfer unit 30 so that the running speed at the first transfer is smaller than the second running speed at the second and subsequent transfers.

  The example which manufactured the board | substrate sheet | seat 10 with the conductive bump 62 with the manufacturing method of the board | substrate sheet with a conductive bump by this invention is demonstrated.

Example 1
Similarly to the case of the second embodiment described above, the substrate sheet 10 with the conductive bumps 62 was manufactured by screen printing using the screen plate 20 held by the frame 27. A metal mask was used as the screen plate 20. The diameter of the through hole 20a of the screen plate 20 was in the range of 50 to 300 μm. The screen plate 20 was set on the frame 27 so that the value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 was 3.0 N / mm. Further, during the transfer, the distance _{s 9} between the substrate sheet 10 on the screen plate 20 and the printing plate 12 was set to 1.5 mm.

A squeegee 32 of the transfer unit 30 was used as a member for pressing the screen plate 20. Also, during transfer and during filling, divided by the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 so as to be 0.5 N / mm, the squeegee 32 has been pushed downward by the arm members 34.

  The conductive paste 60 is a metal paste (silver paste) having a viscosity at a shear rate of 1 (1 / s) of 1070 Pa · s at 20 ° C., 1110 Pa · s at 23 ° C., and 1290 Pa · s at 26 ° C. Or copper paste). These viscosities are values measured by a viscoelasticity measuring device. Further, the temperature and humidity in the vicinity of the screen plate 20 were adjusted to 23 ° C. and 50% using the temperature adjusting mechanism 16 so that the viscosity of the conductive paste 60 at the time of transfer and filling was constant.

  Under the above-described conditions, the printing of the conductive paste 60 on the substrate sheet 10 was repeated in the same manner as in the first embodiment described above. At this time, a copper foil having a thickness of 18 μm was used as the substrate sheet 10. The running speed of the squeegee at the time of transfer and filling was in the range of 5 to 150 mm / s. As a result, by repeating the printing (filling and transfer) of the conductive paste 60 four times on the conductive bumps 62 of the substrate sheet 10 formed by the first transfer, a conductive material having a height of 170 to 180 μm. The bumps 62 could be formed on the substrate sheet 10.

(Example 2)
The screen plate 20 is electrically conductive by screen printing in the same manner as in Example 1 except that the screen plate 20 stretched by a pair of stretching tools 21 (see the third embodiment described above) is used. The board | substrate sheet | seat 10 with the property bump 62 was manufactured. A metal mask was used as the screen plate 20. The screen plate 20 was stretched by a pair of stretching tools 21 so that the value obtained by dividing the tension F ₂ of the screen plate 20 by the width s ₃ of the screen plate 20 was 2.2 N / mm. At this time, in order to reinforce the screen plate 20, sandwiched thickness _{s 6} is 0.2 mm, a width _{s 5} 40 mm, the screen plate 20 from above and below by reinforcing plate 22 which length _{s 4} is made of an aluminum plate of 550 mm. As the fixture 24 for sandwiching the screen plate 20 via the reinforcing plate 22, a fixture having substantially the same width and length as the reinforcing plate 22 was used.

Under the above-described conditions, the printing of the conductive paste 60 on the substrate sheet 10 was repeated in the same manner as in the first embodiment described above. At this time, a copper foil having a thickness of 18 μm was used as the substrate sheet 10. The running speed of the squeegee at the time of transfer and filling was in the range of 5 to 150 mm / s. Further, the distance s ₉ between the one end 20b of the screen plate 20 and the substrate sheet 10 when the transfer unit 30 is in the initial position (see FIG. 1A) is 2 mm, and the transfer unit 30 is in the travel completion position (see FIG. 1 (c) to the distance _{s 9} between the one end 20b and the substrate sheet 10 of the screen plate 20 when in the reference) is 8 mm, and drives the extension tool vertical drive unit 26. As a result, by repeating the printing (filling and transfer) of the conductive paste 60 four times on the conductive bumps 62 of the substrate sheet 10 formed by the first transfer, a conductive material having a height of 170 to 180 μm. The bumps 62 could be formed on the substrate sheet 10.

(Comparative Example 1)
The same as in Example 1 except that the conductive paste 60 was not filled in the through holes 20a after the transfer of the conductive paste 60 to the substrate sheet 10 and that the temperature in the vicinity of the screen plate 20 was adjusted to 20 ° C. Thus, the substrate sheet 10 with the conductive bumps 62 was manufactured by screen printing. As a result, by repeating the printing (transfer) of the conductive paste 60 five times on the conductive bump 62 of the substrate sheet 10 formed by the first transfer, the conductive bump 62 having a height of 170 to 180 μm. Was formed on the substrate sheet 10. As described above, according to Comparative Example 1, the required number of overprints was increased by one as compared with the cases of Examples 1 and 2 described above. This is because, after the conductive paste 60 is transferred to the substrate sheet 10, the conductive paste 60 is not filled in the through holes 20 a, so that the conductive paste 60 transferred to the conductive bumps 62 by one printing is used. This is probably because the amount has decreased.

(Comparative Example 2)
As the value obtained by dividing the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 is 0.2 N / mm, except that the squeegee 32 has been pushed downward by the arm member 34, in the same manner as in Example 1 Thus, the substrate sheet 10 with the conductive bumps 62 was manufactured by screen printing. As a result, by repeating the printing (filling and transfer) of the conductive paste 60 five times on the conductive bumps 62 of the substrate sheet 10 formed by the first transfer, a conductive material having a height of 170 to 180 μm. Bumps 62 were formed on the substrate sheet 10. As described above, according to Comparative Example 2, the required number of times of overprinting was increased by one as compared with the cases of Examples 1 and 2 described above. This is the value of the push pressure F ₁ of the squeegee 32, because it was below the value of the pushing pressure required at the time of filling (pushing pressure lower limit for the filling), conductivity in the through hole 20a of screen plate 20 This is probably because the paste 60 could not be sufficiently filled.

(Comparative Example 3)
As the value obtained by dividing the width s ₈ of the pushing pressure F ₁ squeegee of the squeegee 32 is 1.0 N / mm, except that the squeegee 32 has been pushed downward by the arm member 34, in the same manner as in Example 1 Thus, the substrate sheet 10 with the conductive bumps 62 was manufactured by screen printing. As a result, by repeating the printing (filling and transfer) of the conductive paste 60 five times on the conductive bumps 62 of the substrate sheet 10 formed by the first transfer, the conductive material having a height of 170 to 180 μm. Bumps 62 were formed on the substrate sheet 10. As described above, according to Comparative Example 3, the number of necessary overprints was increased by one as compared with the cases of Examples 1 and 2 described above. This is the value of the push pressure F ₁ of the squeegee 32, because it was above the pushing pressure upper limit value for the transfer, the conductive paste 60 in the through hole 20a of screen plate 20 during the transfer is scraped off by the squeegee 32 This is thought to be due to the fact that it has been closed.

DESCRIPTION OF SYMBOLS 10 Substrate sheet | seat 11 Additional board | substrate sheet | seat 12 Printing surface plate 13 Printing surface plate drive part 14 Surface plate rail 15 Manufacturing apparatus 16 Temperature adjustment mechanism 16a Partition 20 Screen plate 20a Through hole 21 Stretching tool 22 Reinforcement plate 23 Mounting hole 24 Installation Tool 25 Tensioning tool horizontal driving part 26 Tensioning tool vertical driving part 27 Frame 28 Tensioning tool rail 30 Transfer unit 32 Squeegee 32b Lower end of squeegee 34 Arm member 36 Transfer unit main body 38 Squeegee rail 40 Transfer unit 42 Squeegee 44 Arm member 46 Scraper 48 Arm member 49 Transfer unit main body 60 Conductive paste 62 Conductive bumps 70 and 72 Heating roller 74 Insulating sheet 76 Buffer material 80 Multilayer printed wiring board

Claims (13)

Preparing a screen plate provided with a plurality of through holes;
By pressing the conductive paste on the screen plate into the through hole of the screen plate, the conductive paste is transferred onto the substrate sheet below the screen plate through the through hole, and the conductive paste is transferred. Forming a conductive bump on the substrate sheet by drying the substrate sheet,
After transferring the conductive paste onto the substrate sheet, filling the through hole of the screen plate with the conductive paste;
After filling the through hole of the screen plate with a conductive paste, the conductive paste of the substrate sheet is pressed through the through hole by pressing the conductive paste on the screen plate against the through hole of the screen plate. Transferring the conductive paste onto the bumps;
Drying the substrate sheet with the conductive paste transferred onto the conductive bumps;
A method for producing a substrate sheet with conductive bumps, comprising:   After transferring the conductive paste on the substrate sheet, filling the through hole of the screen plate with the conductive paste, filling the through hole of the screen plate with the conductive paste, and then on the screen plate A step of transferring the conductive paste onto the conductive bumps of the substrate sheet through the through holes by pressing a certain conductive paste against the through holes of the screen plate, and the conductive paste on the conductive bumps The method for producing a substrate sheet with conductive bumps according to claim 1, wherein a series of steps comprising the step of drying the substrate sheet having transferred thereon is performed once or a plurality of times. When transferring the conductive paste onto the substrate sheet, the conductive paste on the screen plate is pressed to the through hole of the screen plate by a pressing member,
3. The conductive bump according to claim 1, wherein when the conductive paste is filled into the through hole of the screen plate, the conductive paste is filled into the through hole of the screen plate by the pressing member. Manufacturing method of attached substrate sheet. When transferring the conductive paste onto the substrate sheet, the conductive paste on the screen plate is pressed into the through hole of the screen plate by the first pressing member,
When the conductive paste is filled into the through hole of the screen plate, the conductive paste is filled into the through hole of the screen plate by a second pressing member provided integrally with the first pressing member. The method for producing a substrate sheet with conductive bumps according to claim 1 or 2. When the assembly composed of the first pressing member and the second pressing member moves in one direction on the screen plate, the conductive paste is transferred onto the substrate sheet by the first pressing member,
Filling the through hole of the screen plate with the conductive paste by the second pressing member when the combined body moves on the screen plate in another direction opposite to the one direction. The manufacturing method of the board | substrate sheet | seat with an electroconductive bump of Claim 4 characterized by the above-mentioned.   The tension of the screen and the pressing pressure of the pressing member when transferring the conductive paste onto the substrate sheet are the tension of the screen and the pressing member when filling the through hole of the screen plate with the conductive paste. 4. The method for producing a substrate sheet with conductive bumps according to claim 3, wherein the indentation pressure is the same. The value obtained by dividing the tension of the screen plate by the width of the screen plate is in the range of 1.4 to 3.6 N / mm,
The substrate sheet with conductive bumps according to claim 6, wherein a value obtained by dividing the pressing pressure of the pressing member by the width of the pressing member is in a range of 0.3 to 0.9 N / mm. Manufacturing method. The screen plate is stretched by a pair of stretching tools,
The conductive extension bumper according to claim 6, wherein the extension tool includes a fixture for sandwiching the screen plate, and a reinforcing plate interposed between the fixture and the screen plate. A method for manufacturing a substrate sheet.   The method for producing a substrate sheet with conductive bumps according to claim 8, wherein the thickness of the reinforcing plate is equal to or greater than the thickness of the screen plate. At least one tensioning tool among the pair of tensioning tools is movable in the vertical direction,
The vertical distance between one end of the screen plate supported by the at least one tensioning tool and the substrate sheet is in a range of 0.5 to 10 mm. The manufacturing method of the board | substrate sheet | seat with the conductive bump of description.   The method for producing a substrate sheet with conductive bumps according to any one of claims 1 to 10, wherein temperature and humidity in the vicinity of the screen plate are kept constant by a temperature adjusting mechanism that covers the screen plate from above. . Preparing a screen plate provided with a plurality of through holes;
By pressing the conductive paste on the screen plate into the through hole of the screen plate, the conductive paste is transferred onto the substrate sheet below the screen plate through the through hole, and the conductive paste is transferred. Forming a conductive bump on the substrate sheet by drying the substrate sheet,
After transferring the conductive paste onto the substrate sheet, filling the through hole of the screen plate with the conductive paste;
After filling the through hole of the screen plate with a conductive paste, the conductive paste of the substrate sheet is pressed through the through hole by pressing the conductive paste on the screen plate against the through hole of the screen plate. Transferring the conductive paste onto the bumps;
Drying the substrate sheet with the conductive paste transferred onto the conductive bumps;
An insulating sheet is superimposed on a substrate sheet with conductive bumps having conductive bumps formed by transferring the conductive paste a plurality of times, and the conductive bumps are formed by sandwiching and heating the stacked body. A process of penetrating the insulating sheet;
A step of superimposing an additional substrate sheet on the surface of the insulating sheet, and electrically connecting the conductive bumps penetrating the insulating sheet and the superimposed additional substrate sheet;
A method for producing a multilayer printed wiring board, comprising:   After transferring the conductive paste on the substrate sheet, filling the through hole of the screen plate with the conductive paste, filling the through hole of the screen plate with the conductive paste, and then on the screen plate A step of transferring the conductive paste onto the conductive bumps of the substrate sheet through the through holes by pressing a certain conductive paste against the through holes of the screen plate, and the conductive paste on the conductive bumps The method for producing a multilayer printed wiring board according to claim 12, wherein a series of steps comprising the step of drying the substrate sheet having transferred thereon is performed once or a plurality of times.

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