JP5109900B2 - Method for manufacturing substrate sheet with conductive bump - Google Patents

Description

  The present invention relates to a method of manufacturing a substrate sheet with conductive bumps used when manufacturing a multilayer printed wiring board.

  Conventionally, a flexible screen mask (screen plate) having a hole (through hole) for holding a conductive paste at a predetermined position is stretched on the surface of a substrate to be printed (surface of a base material). The conductive paste placed on the screen mask is filled in the space defined by the holding holes and the surface of the printing medium by moving the squeegee member that presses the surface of the printing body along the surface of the printing body. A method of forming a paste bump in which a conductive paste filled in a space with a tensile force when the screen mask is separated from the surface of the printing body is formed into a substantially conical shape, between the screen mask and the printing body. There is known a method of moving a squeegee member in a state where a hole lower surface and a printing medium are slightly separated from each other by interposing a spacer (see Patent Document 1 and Patent Document 2).

  According to such a method, a conductive bump having a desired height can be formed with a small number of printings, and the manufacturing time of the substrate with conductive bumps can be shortened.

Further, when the number of screen printing process executions is a, and the rate of occurrence of defects in one screen printing process is b, the yield rate is (1−b) ^a ≈1−a × b, and the screen printing process is executed. As the number of times increases, the yield rate in the production of the substrate sheet with conductive bumps decreases. However, according to the method described above, the number of executions of the screen printing process can be reduced, so the yield rate is increased. can do.
Japanese Patent Laid-Open No. 2004-6577 JP 2003-320640 A

  However, in the conventional method described above, a spacer is interposed between the screen mask and the printing medium in order to move the squeegee member in a state where the hole lower surface and the printing medium are slightly separated from each other. For this reason, the spacer may be peeled off when cleaning the screen mask, and it is difficult to continue using the screen mask for a long time. In the first place, it is difficult to manufacture a screen mask with spacers in this way.

  The present invention has been made in consideration of such points, and can reduce the number of steps of applying a conductive paste to the surface of a substrate sheet, and can use a screen plate for a long period of time. Provided is a method for manufacturing a substrate sheet with conductive bumps that can be continued and can easily realize transfer of the conductive paste with the screen plate and the substrate slightly spaced apart from each other. For the purpose.

The method for producing a substrate sheet with conductive bumps according to the present invention comprises:
A flat plate member having a plurality of flat plate raised portions and having a flat plate concave portion formed at the center of each flat plate raised portion and placed on the flat plate member by the printing surface plate, A base material holding step for holding a base material including a substrate sheet having a corresponding substrate raised portion and a substrate sheet in which a substrate recess is formed at the center of each substrate raised portion,
A positioning step of positioning a screen plate having a plurality of through holes on the base material, and aligning the substrate concave portions of the substrate raised portions of the substrate sheet and the through holes of the screen plate,
A base material transfer step of transferring a conductive paste from the through hole of the screen plate to the substrate recess of the substrate bulge portion of the substrate sheet;
It is provided with.

In the method for producing a conductive bumped substrate sheet according to the present invention,
It is preferable that the flat plate raised portion in which the flat plate concave portion is formed in the center is formed in an annular shape, and the substrate raised portion corresponding to the flat plate raised portion is also formed in an annular shape.

  Alternatively, the flat plate raised portion in which the flat plate concave portion is formed in the center may be a polygonal shape, and the substrate raised portion corresponding to the flat plate raised portion may also be a polygonal shape.

In the method for producing a conductive bumped substrate sheet according to the present invention,
It is preferable to further include a base material positioning step for positioning the base material with respect to the printing surface plate so that the conductive paste is placed in the substrate concave portion of the substrate rising portion of the substrate sheet.

At this time,
The base material positioning step includes a base material image acquisition step of acquiring an image of a base material held on the printing surface plate by an image acquisition device, and a base for displaying an image acquired by the image acquisition device by an image display device. It is more preferable to include a material image display step and a substrate position adjustment step of adjusting the position of the substrate with respect to the printing surface plate based on the image displayed by the image display device.

  According to the present invention, the substrate bulge portion of the substrate sheet realizes a state in which the screen plate and the base material are slightly separated, and the conductive paste is transferred to the recess formed in the center of the substrate bulge portion. Let For this reason, the number of steps of applying the conductive paste to the surface of the substrate sheet can be reduced, and the screen plate can be used for a long time, and the space between the screen plate and the base material can be reduced. It is possible to easily transfer the conductive paste in a slightly spaced state. In addition, since the conductive paste is transferred to the recess formed in the center of the substrate bulge portion, the conductive paste is blocked by the substrate bulge portion, and the conductive paste transferred to the substrate sheet bleeds. Can be suppressed. This can prevent the bottom diameter of the conductive bump from becoming large.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment Hereinafter, an embodiment of the conductive bumps substrate sheet manufacturing method according to the present invention will be described with reference to the drawings. Here, FIG. 1 to FIG. 8 are diagrams showing an embodiment of the present invention.

  In the present embodiment, the substrate sheet manufacturing system with conductive bumps is a substrate raised portion generating device that forms a substrate raised portion 61a having a substrate recessed portion 61b formed in the center on the substrate (see FIGS. 1A and 1B). And a printing device (see FIG. 3) for transferring the conductive paste 70 to the substrate recess 61b of the substrate raised portion 61a of the substrate sheet 61.

  As shown in FIGS. 1 (a) and 1 (b), the substrate swell portion generating apparatus includes a holding unit 1 that holds and holds a flat plate member 62 having a plurality of flat plate swell portions 62a by a suction force from the suction holes 1a. Then, pressure is applied to the substrate sheet 61 (for example, metal foil) placed on the flat plate raised portion 62 a of the flat plate member 62, and the substrate corresponding to the flat plate raised portion 62 a of the flat plate member 62 is applied to the substrate sheet 61. And a pressure roller (pressure part) 10 that forms the raised part 61a. Note that the flat plate member 62 is provided with an opening (not shown), and the substrate sheet 61 is held by an adsorption force through the opening.

  Here, as shown in FIG. 2A, a flat plate recess 62 b is formed at the center of the flat plate raised portion 62 a of the flat plate member 62. Further, as shown in FIG. 1C and FIG. 2B, a substrate recess 61b is also formed at the center of the substrate raised portion 61a corresponding to the flat plate raised portion 62a formed by the pressure roller 10. . More specifically, as shown in FIGS. 2A and 2B, the flat plate raised portion 62a in which the flat plate recess 62b is formed in the center has a crater-like shape with a depressed central portion (that is, The substrate raised portion 61a in which the substrate concave portion 61b is formed in the center also has a crater shape (that is, an annular shape) in which the center portion is recessed. The shape of the substrate raised portion 61a and the flat plate raised portion 62a is not limited to an annular shape as shown in FIGS. 2 (a) and 2 (b). For example, as shown in FIG. 2 (c). A polygonal shape (for example, a hexagonal shape) may be used.

  By the way, as the flat member 62, metal sheets, such as copper, SUS, and aluminum, films and resin sheets, such as PET, PP, and PE, can be used. Moreover, as the pressure roller 10, a rubber roll, a metal roll, a resin roll, etc. can be used.

  Further, in the present embodiment, the pressure roller 10 is used as a pressure portion for forming the substrate raised portion 61a corresponding to the flat plate raised portion 62a of the flat plate member 62 on the substrate sheet 61 (FIG. 1A). ) (See (b)), without being limited thereto, for example, a flat press may be used.

  As shown in FIG. 3, the printing apparatus includes a printing surface plate 30 that holds a substrate 60, a screen plate 27 such as a metal mask provided with a plurality of through holes 27a having a predetermined pattern, and the screen. A holding portion 26 for holding the plate 27 and a conductive paste 70 (see FIG. 6) such as a silver paste and a solder paste, which is scanned on the screen plate 27 and is placed on the screen plate 27, are formed through the through holes 27a. And a squeegee 22 to be transferred onto the substrate sheet 61 of the material 60. The squeegee mechanism 20 includes the squeegee 22 described above and the guide member 21 that guides the squeegee 22. Here, the base material 60 includes a flat plate member 62 having a plurality of flat plate raised portions 62a, and a substrate sheet 61 which is placed on the flat plate member 62 and has a substrate raised portion 61a corresponding to the flat plate raised portions 62a. It is made up of. In addition, as described above, the substrate recess 61b is formed in the center of each substrate raised portion 61a of the substrate sheet 61 of the base material 60.

  As shown in FIG. 3, a CCD camera (image acquisition device) 11 that acquires an image of the substrate 60 held on the printing surface plate 30 is disposed on the upstream side of the squeegee mechanism 20. The CCD camera 11 is connected to a display screen (image display device) 12 for displaying an image acquired by the CCD camera 11.

  As shown in FIG. 3, the printing surface plate 30 includes a position adjusting device 35 that adjusts the position of the base material 60 with respect to the printing surface plate 30. The position adjustment unit 35 is connected to a position instruction unit 16 that transmits an instruction input by an operator. The base material 60 is provided with an alignment mark (not shown), and the position of the base material 60 relative to the printing surface plate 30 is positioned by photographing the alignment mark with the CCD camera 11.

  In the present embodiment, the CCD camera 11, the display screen 12, the position adjustment device 35, and the position instruction unit 16 described above constitute a positioning mechanism that positions the base material 60 with respect to the printing surface plate 30. A guide member 31 for guiding the printing surface plate 30 extends in the horizontal direction below the printing surface plate 30.

  Further, as shown in FIGS. 4A and 4B, the position adjusting device 35 is provided with a suction hole 35a, and the base member 60 is held by the suction force from the suction hole 35a. . In the present embodiment, a description will be given using a mode in which the base material 60 is adsorbed and held by the suction holes 35a of the position adjusting device 35 as described above. However, the present invention is not limited to this. A suction plate may be provided on the position adjustment device 35, and the base member 60 may be sucked and held by the suction force from the suction plate.

  Next, the operation of the present embodiment having such a configuration will be described.

(Generation of the substrate sheet 61 having the substrate raised portion 61a)
First, a process of generating the substrate sheet 61 having the substrate raised portion 61a in which the substrate recess 61b is formed at the center will be described.

  First, the flat plate member 62 having a plurality of flat plate raised portions 62a is sucked and held by the suction force from the suction hole 1a of the holding portion 1 (see FIG. 1A). Here, as shown in FIG. 2A, a flat plate recess 62b is formed at the center of the flat plate raised portion 62a. Next, the plurality of flat plate raised portions 62a of the flat plate member 62 are brought into contact with the substrate sheet 61 (contact step). More specifically, the substrate sheet 61 is placed on the flat plate member 62 (see FIG. 1A).

  Next, the pressure roller 10 is moved in the horizontal direction with the substrate sheet 61 pressed against the flat plate member 62 (see FIG. 1A). At this time, pressure is applied to the substrate sheet 61 by the pressure roller 10, and substrate swell portions 61 a corresponding to the plurality of plate swell portions 62 a of the plate-like member 62 are formed on the substrate sheet 61 (substrate swell portion). Forming step) (see FIG. 1B). At this time, since the flat plate recess 62b is formed at the center of the flat plate raised portion 62a, the substrate concave portion 61b corresponding to the flat plate recess 62b is also formed at the center of the substrate raised portion 61a (FIG. 1). (See (c) and FIG. 2 (b)). Here, it is desirable that the outer diameter of the substrate raised portion 61a formed as described above is substantially the same as or smaller than the outer diameter of the finally formed conductive bump. Further, it is desirable that the substrate swell portion 61a has a hardness that does not break even with a screen printing squeegee pressure (about 0.25 MPa).

(Generation of substrate sheet with conductive bumps)
Next, a process of generating a substrate sheet with conductive bumps will be described.

  First, by the position adjusting device 35 of the printing surface plate 30, a base material 60 composed of a flat plate member 62 having a plurality of flat plate raised portions 62 a and a substrate sheet 61 having a substrate raised portion 61 a corresponding to the flat plate raised portions 62 a. And adsorbed and held (base material holding step) (see FIG. 3). The base material 60 is placed on the printing surface plate 30 such that the flat plate member 62 is located below and the substrate sheet 61 is located above.

  Next, the base material 60 is placed on the printing platen 30 so that the conductive paste 70 transferred by the squeegee mechanism 20 is placed on the substrate recess 61b formed at the center of the substrate raised portion 61a of the substrate sheet 61. It is positioned with respect to (base material positioning step) (see FIG. 3).

  Specifically, first, an image of the substrate 60 held on the printing surface plate 30 is taken by the CCD camera 11 (substrate image acquisition step). Next, the image of the base material 60 thus captured by the CCD camera 11 is displayed on the display screen 12 (base material image display step).

  Next, the operator inputs an instruction to the position instruction unit 16 so as to move the printing surface plate 30 to a predetermined position based on the image displayed on the display screen 12. Then, according to this instruction, the position adjusting device 35 is driven, and the position of the substrate 60 with respect to the printing surface plate 30 is adjusted. For example, the operator inputs an instruction to the position instruction unit 16 so that the alignment mark on the base material 60 is photographed at the center position of the CCD camera 11. Then, in accordance with this instruction, the position adjusting device 35 is driven, and the position of the substrate 60 relative to the printing surface plate 30 is adjusted so that the alignment mark is at the center position of the CCD camera 11 (substrate position adjusting step).

  Next, the printing surface plate 30 is moved in the horizontal direction (right side in FIG. 5) along the guide member 31 by a driving force applied from a driving unit (not shown) (see FIG. 5). As a result, the screen plate 27 having a plurality of through holes 27a is positioned on the substrate 60 (positioning step) (see FIG. 4A). Specifically, as shown in FIG. 4A, the positions of the substrate recess 61 b of each substrate raised portion 61 a of the substrate sheet 61 and the through hole 27 a of the screen plate 27 are aligned.

  Next, the squeegee 22 is scanned on the screen plate 27 along the guide member 21, and the conductive paste 70 placed on the screen plate 27 is transferred onto the substrate sheet 61 of the substrate 60 through the through hole 27a. (Base material transfer step) (see FIG. 4B and FIG. 6).

  Here, according to the present embodiment, as described above, the printing surface plate 30 can be moved to a predetermined position based on the image displayed on the display screen 12 before the substrate transfer step. Therefore, in this base material transfer step, the conductive paste 70 transferred through the through hole 27a of the screen plate 27 by the squeegee 22 of the squeegee mechanism 20 is formed at the center of the substrate raised portion 61a of the substrate sheet 61. It can be reliably transferred to the substrate recess 61b (see FIG. 8).

  For this reason, the height of the conductive bumps can be made sufficient by transferring the conductive paste 70 onto the substrate sheet 61 once by the squeegee 22 of the squeegee mechanism 20. As a result, the number of steps of applying the conductive paste 70 to the surface of the substrate sheet 61 can be reduced, and as a result, the manufacturing time of the substrate with conductive bumps can be shortened. Moreover, the yield rate in manufacture of a board | substrate sheet | seat with an electroconductive bump can also be made high.

  As described above, when the conductive paste 70 is placed on the substrate recess 61b of the substrate raised portion 61a of the substrate sheet 61, the printing surface plate 30 moves in the horizontal direction (left side in FIG. 7) and returns to the initial position. (See FIG. 7). At this time, the squeegee mechanism 20 also returns to the initial position (see FIG. 7).

  Next, the substrate sheet 61 is peeled from the flat plate member 62. Thereafter, the conductive paste 70 provided in each substrate recess 61b of the substrate sheet 61 is dried and cured (base material curing step). As a result, substantially conical conductive bumps are formed on the substrate sheet 61, and a substrate sheet with conductive bumps is generated. In the case where the conductive paste 70 is made of an ultraviolet curable material, instead of drying the conductive paste 70, the conductive paste 70 may be cured by irradiating with ultraviolet rays.

  When the substrate sheet with conductive bumps is generated as described above, an uncured insulating sheet (not shown) is placed on the substrate sheet with conductive bumps and pressed. As a result, the conductive bump penetrates the insulating sheet, and the insulating sheet is positioned on the substrate sheet with the conductive bump.

  Next, another (with conductive bumps) substrate sheet (the uppermost substrate sheet 61 has no conductive bumps) is placed on the uncured insulating sheet and then pressed. As a result, the conductive bumps of the substrate sheet with conductive bumps positioned below penetrate into the back surface of the substrate sheet positioned with the conductive bumps (with the conductive bumps). Next, the insulating sheet is cured, and then a circuit is formed on the substrate sheet (with conductive bumps).

  A multilayer printed wiring board will be manufactured by repeating such a process.

  By the way, according to the present embodiment, as shown in FIGS. 4A and 4B, the screen plate 27 and the base material 60 can be slightly separated by the substrate raised portion 61a (gap). Since G is provided), it is not necessary to use a spacer as in the prior art to increase the transfer amount of the conductive paste 70 from the screen plate 27 to the substrate sheet 61. For this reason, the spacer is not peeled off when the screen plate 27 is washed, and the screen plate 27 can be used for a long time.

  In addition, according to the present embodiment, each conductive bump is formed on the substrate bulge portion after the conductive paste 70 is transferred to the substrate recess 61b until the conductive paste 70 is dried to form the conductive bump. It will be delimited by 61a. For this reason, even when the diameter of the conductive paste 70 is large, it is possible to prevent the adjacent conductive pastes 70 from being connected to each other, and thus to prevent a short circuit from occurring in the multilayer printed wiring board. can do.

(A) (b) is a schematic side view which shows the structure of the board | substrate rising part production | generation apparatus by embodiment of this invention, (c) is the flat board rising part of the flat member shown in (b), and a board | substrate sheet | seat. The enlarged side view of a board | substrate rising part. (A) is a perspective view of a flat plate-like member having a flat plate raised portion, (b) is a perspective view of the flat plate-like member and a substrate sheet placed thereon, and (c) is a flat plate shape of another shape. The perspective view of the board | substrate sheet | seat of the other shape mounted on the member and it. 1 is a schematic side view of a printing apparatus according to an embodiment of the present invention as viewed from the side. The expanded side view which showed the positioning process and base-material transfer process in the squeegee mechanism by embodiment of this invention. FIG. 3 is a schematic side view showing one driving state of the printing apparatus according to the embodiment of the present invention. FIG. 6 is a schematic side view showing the printing apparatus in a state advanced from the state shown in FIG. 5. The schematic side view which showed the printing apparatus in the state advanced from the state shown in FIG. The expanded side view which shows the electrically conductive paste transcribe | transferred to the board | substrate recessed part of the board | substrate rising part of a board | substrate sheet | seat.

Explanation of symbols

1 Holding part 10 Pressure roller (Pressure part)
11 CCD camera (image acquisition device)
DESCRIPTION OF SYMBOLS 12 Image display apparatus 22 Squeegee 27 Screen plate 27a Through-hole 30 Printing surface plate 35 Position adjustment apparatus 60 Base material 61 Substrate sheet 61a Substrate rise part 61b Substrate recessed part 62 Flat plate member 62a Flat plate raised part 62b Flat plate concave part 70 Conductive paste

Claims (5)

A flat plate member having a plurality of flat plate raised portions and having a flat plate concave portion formed at the center of each flat plate raised portion and placed on the flat plate member by the printing surface plate, A base material holding step for holding a base material including a substrate sheet having a corresponding substrate raised portion and a substrate sheet in which a substrate recess is formed at the center of each substrate raised portion,
A positioning step of positioning a screen plate having a plurality of through holes on the base material, and aligning the substrate concave portions of the substrate raised portions of the substrate sheet and the through holes of the screen plate,
A base material transfer step of transferring a conductive paste from the through hole of the screen plate to the substrate recess of the substrate bulge portion of the substrate sheet;
A method for producing a substrate sheet with conductive bumps, comprising:   The flat plate raised portion in which the flat plate concave portion is formed in the center is made of an annular shape, and the substrate raised portion corresponding to the flat plate raised portion is also made of an annular shape. 2. A method for producing a substrate sheet with conductive bumps according to 1.   The flat plate raised portion in which the flat plate concave portion is formed at the center is made of a polygonal shape, and the substrate raised portion corresponding to the flat plate raised portion is also made of a polygonal shape. 2. A method for producing a substrate sheet with conductive bumps according to 1.   The method further comprises a base material positioning step of positioning the base material with respect to the printing surface plate so that a conductive paste is placed in the substrate concave portion of the substrate rising portion of the substrate sheet. The method for producing a substrate sheet with conductive bumps according to claim 1.   The base material positioning step includes a base material image acquisition step of acquiring an image of a base material held on the printing surface plate by an image acquisition device, and a base for displaying an image acquired by the image acquisition device by an image display device. 5. The method according to claim 4, further comprising: a material image display step; and a base material position adjustment step of adjusting a position of the base material with respect to the printing surface plate based on an image displayed by the image display device. A method for producing a substrate sheet with conductive bumps.

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