JP2003133723A - Conductive paste packing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paste packing method and device whose productivity is excellent capable of surely packing a fine via formed at a substrate with high viscosity paste. SOLUTION: The back side of a substrate 501 is adhesively held, and squeezee 104 is adhesively disposed at the surface side of the substrate 501, and shear stress to be defined by the product of the viscosity of paste 202 supplied to the front port of the traveling direction of the squeezee 104 and the squeezee moving speed is detected, and the squeezee 104 is moved while the moving speed of the squeezee 104 is controlled so that the shear stress can be made constant, and a fine via 502 is packed with the paste 202. The shear stress is detected by a strain gauge 104c attached to the edge part of the squeezee 104 or an elevating shaft 104b of the squeezee 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for manufacturing double-sided or multi-layer wiring boards used in various electronic devices, and more particularly to a method and apparatus for filling a conductive paste in a minute via.

[0002]

2. Description of the Related Art As a first conventional example, Japanese Patent Laid-Open No. 5-237.
FIG. 6 shows a representative drawing of a filling method and filling device for a high-viscosity conductive paste disclosed in Japanese Patent No. 986. Or later,
The conductive paste is abbreviated to paste. This is a device that fills the vias with paste using a roller squeegee. The roller squeegee 604 is brought into close contact with the mask plate 605 which is closely placed on the base material 601, and the roller squeegee 604 is moved relative to the base material 601 while being rotated, so that the paste 60 on the surface of the mask plate 605.
Through the supply of No. 3, the through via 602 is filled with the paste 603. A mask hole 606 is provided in the mask plate 605 so as to match the position of the through via 602.

Next, the filling operation will be described. With the roller squeegee 604 in close contact with the mask plate 605,
When the roller squeegee 604 is rotated and moved in the horizontal direction with respect to the base material 601, the paste 603 supplied to the front side in the moving direction of the roller squeegee 604 is wound backward in the moving direction by the rotational force of the roller squeegee 604. Further, when the paste 603 passes between the peripheral surface of the roller squeegee 604 and the surface of the mask plate 605, the paste 603 is filled and pressed into the mask hole 606 and the through via 602 by the peripheral surface of the roller squeegee 604. At this time, filling,
The air in the through vias 602 is discharged from the back surface of the base material 601 by the pressed paste 603, so that the vias can be filled with the paste at a high density.

As a second conventional example, FIG. 7 shows a paste filling apparatus using a vacuum chamber for filling a paste into a minute blind via. When filling the fine blind vias 702 provided in the base material 701 with the paste 603, the inside of the vacuum chamber 703 connected to a vacuum evacuation unit (not shown) is evacuated, and then the squeegee 70.
4 is brought into contact with the surface of the mask plate 705 closely arranged on the base material 701. A mask hole 706 is provided in the mask plate 705 so as to match the position of the minute blind via 702.

Further, the squeegee 7 on the surface of the mask plate 705
04 The paste 603 is supplied to the front side in the moving direction, the squeegee 704 is moved relative to the mask plate 705,
The paste 603 is applied by printing onto the mask plate 705. After that, the inside of the vacuum chamber 703 is opened to the atmosphere, so that the paste 603 printed and applied to the minute blind vias 702 by the action of atmospheric pressure is filled at a higher density.

When the paste 603 is printed and applied by the squeegee 704 while the vacuum chamber 703 is in a vacuum state, at least the mask holes 70 provided in the mask plate 705 are provided.
6 and the surface portions of the small blind vias 702 are filled with the paste 603. Here, the unfilled void of the paste 603 at the bottom of the minute blind via 702 is in a vacuum state. After that, when the vacuum chamber 703 is opened to the atmosphere, the minute blind via 702 is generated due to the pressure difference.
The paste 603 already filled in the mask holes 706 of the mask plate 705 is replenished and filled in the unfilled voids in the blind via bottom portion. Then, the squeegee 704 is brought into contact with the base material 701, and the paste 603 remaining on the base material 701.
To scrape off.

[0007]

When a paste having a high viscosity due to the miniaturization of the conductive filler is filled in the fine vias, the resin component or the solvent component contained in the conductive paste increases as the number of printed sheets increases. It is reduced by being attached to or vaporized, and the paste viscosity is further increased to increase the paste filling resistance. As a result, it is difficult to reliably fill the high-viscosity paste in the minute via even with the pressing action of the paste by the peripheral surface of the rotating roller squeegee in the first conventional example.

In the second conventional example, it is necessary to evacuate the inside of the vacuum chamber, print the paste with a squeegee, and open the atmosphere in the vacuum chamber for filling. Takes a long time.
In addition, since it is necessary to incorporate a mechanism for printing and applying a paste into the vacuum chamber, the apparatus volume is already large, and the above procedure needs to be repeated every time the paste is filled for each base material. Remarkably reduces productivity.

Further, in the use of high viscosity paste,
In addition to the fact that vacuum defoaming in the vacuum chamber tends to be uncertain, the high-viscosity paste is repeatedly defoamed in the vacuum chamber at each printing and coating process, and the resin component added to the paste is discharged as a gas. The paste viscosity is significantly increased in a shorter time. Therefore, the paste filling failure and the paste usage amount are shortened and the paste usage amount is increased.

[0010]

In view of the above problems, the present invention can reliably fill a high-viscosity paste in a minute via provided in a base material, reduce the amount of paste used, and have excellent productivity. Another object of the present invention is to provide a paste filling method and a paste filling device.

According to the first aspect of the present invention, the shear stress defined by the product of the viscosity of the conductive paste supplied to the front of the squeegee and the moving speed of the squeegee is the best filling result of the paste in the via as a result of the experiment conducted in advance. The present invention relates to a paste filling method for filling a paste in a minute via reliably and with high density by controlling a squeegee moving speed so as to match the shear stress when a state is shown. That is, when the paste viscosity is low, the moving speed of the squeegee is high, and the moving speed of the squeegee is decreased as the paste viscosity increases.

According to a second aspect of the present invention, the back surface side of the base material is held in close contact, a squeegee is closely arranged on the front surface side of the base material, a conductive paste is supplied to the front side in the moving direction of the squeegee, and a squeegee end portion is provided. The conductive paste filling method according to claim 1, wherein shear stress is detected by a shear stress detector attached to and the moving speed of the squeegee is controlled so as to obtain a constant shear stress. Therefore, the shear stress is detected by a shear stress detector attached to the end of the squeegee. The squeegee control and the moving speed of the squeegee through the drive circuit so that the detected value from the shear stress detector and the value of the shear stress when the best filling state is shown as a result of the experiment conducted in advance become equal. Is controlled, and the conductive paste is filled into the minute vias.

According to a third aspect of the present invention, the back surface side of the base material is held in close contact, a squeegee is closely arranged on the front surface side of the base material, a conductive paste is supplied to the front side in the traveling direction of the squeegee, and the squeegee ends. Shear stress is detected by the attached shear stress detector, and the value of the shear stress signal is compared with the value of the shear stress signal when the best filling state of the via of the paste obtained in advance is shown. The paste filling device has a function of automatically controlling the moving speed of the squeegee so as to match. According to this device, the moving speed of the squeegee is automatically adjusted even if the viscosity changes, and the best filling state of the paste in use at all times is stably obtained, improving the yield and efficiency of the paste filling work, And it becomes possible to reduce the paste consumption.

The same effect can be obtained by mounting the shear stress detector on the lifting shaft of a squeegee. in this case,
Although the detection sensitivity is reduced, paste does not adhere to the strain gauge, which facilitates maintenance.

A fourth aspect of the present invention relates to a method and a paste filling device for filling a paste into a minute blind via.
After filling the blind vias with the paste by the method of the first aspect of the present invention to the base material provided with micro blind vias, the base material is allowed to reach a predetermined vacuum degree, and This is a method of defoaming air bubbles, then opening to the atmosphere, and filling the paste into the minute blind vias again by the method of the first aspect of the present invention. Although this method requires two filling steps, it is possible to reliably fill the blind vias with paste at a high density.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) FIG. 5A is a sectional view showing the structure of a base material and vias according to Embodiment 1. As the base material 501, a base material film 5 having a thickness of about 0.02 mm
01a was used with a cover film 501b attached on both sides. Further, the minute vias are irradiated with an ultraviolet laser from one surface of the cover film 501b of the base material 501 to open a predetermined number of via holes 502 having a hole diameter of about 0.05 mm penetrating the base material 501 at predetermined positions. .

As the paste to be filled in the via 502 to form the conductor circuit in the via, a conductive paste containing copper powder as a main component was used. The conductive paste is a copper powder having an average particle size of 1 μm as a conductive filler, and a thermosetting epoxy resin (solventless type) as a resin,
An acid anhydride type curing agent was used as the curing agent. The mixing ratio was 85% by weight of copper powder, 12.5% by weight of epoxy resin, and 2.5% by weight of curing agent, and they were sufficiently kneaded. The viscosity change due to the filling experiment using the squeegee was 30 Pa · S before the start of filling, but after filling about 100 base materials, the resin component in the paste adhered to the base material surface, The paste viscosity is 150 Pa · S due to penetration.
Was rising up.

Next, the overall structure of the paste filling device according to the first embodiment will be described with reference to FIG. The paste filling device includes a base 101 and a plate frame 102.
A guide shaft 103, a squeegee 104, a shear stress detector 104c, a support 104a, a squeegee drive mechanism and a squeegee control circuit (not shown) provided inside the support, and a vertical lift guide shaft 104b. Composed of and. The shear stress detector 104c has an opening at the end of the squeegee 104 (outside the paste filling area, inside the plate frame), and is attached inside the opening. When the base material is composed of a matrix arrangement of unit wiring boards, an opening is provided in the squeegee portion corresponding to the boundary line of the unit wiring boards in the moving direction of the squeegee, and a shear stress detector is provided in the opening. May be attached. The same effect can be obtained even if the shear stress detector is attached to the lower end of the lifting shaft of the squeegee. In this case, the detection sensitivity is reduced, but the paste does not adhere to the strain gauge, which facilitates maintenance.

In the apparatus having the above-mentioned structure, the base material is held in close contact with the base, the squeegee 104 is placed in close contact with the plate frame 102, and the viscosity of the paste supplied in the forward direction of the squeegee 104 and the moving speed of the squeegee 104 are determined. The shear stress defined by the product is detected by the shear stress detector 104c, and while the moving speed of the squeegee 104 is appropriately controlled, the paste is passed through the minute vias to fill the vias.

FIG. 2 is a sectional view of the main part of the paste filling device, and a more detailed structure will be described. First, in order to uniformly hold and fix the base material 501 so that wrinkles and undulations do not occur, a myriad of suction holes for vacuum adsorption are formed in at least an area inside the outer shape of the base material 501 and made of porous sintered metal. 20
A suction member 201 provided with 1a is embedded in the upper surface of the base 101. A plurality of suction grooves 2 are provided on the lower surface of the suction member 201.
01b is provided, and the suction grooves 201b are assembled together and then penetrate through the inside of the base 101 to provide a vacuum exhaust port 2
From 01c, vacuum pumping means such as a vacuum pump (not shown)
Is evacuated by.

Further, the base upper surface 101a of the base 101, including the base material holding surface 201d on the upper surface of the suction member 201, is finished to a flatness of 0.02 mm or less, so that a step with the base material holding surface 201d is generated. The base material 501 is uniformly held and fixed without doing so. It should be noted that the paste to the suction hole 201a is interposed between the base material 501 and the base material holding surface 201d by interposing a thin air-permeable thin paper 101e having a uniform thickness of about 0.03 mm which exceeds the base material 501 at least. Two
02 is prevented.

A plate frame 102 abutting on the outer peripheral portion of the base material 501, which is held and fixed on the base 101, excluding the paste filling area.
The plate frame elevating guide (not shown) and the plate frame elevating drive mechanism (not shown) allow the plate frame elevating movement in parallel with the base material holding surface 201d. As a result, it is possible to make uniform contact with the outer peripheral portion of the base material 501 of the plate frame 102 excluding the paste filling area.

Further, at least two corners of the inner periphery of the plate frame 102, which are orthogonal to the squeegee moving direction, are chamfered at 60 degrees to form a sloped edge 102a in the shape of a knife edge having a tip angle of 30 degrees. It is provided. Further, the upper surfaces of the inclined portion 102a and the plate frame 102 are mirror-finished by buffing. Accordingly, the upper surface of the plate frame 102 and the inclined portion 102a can be moved smoothly when the squeegee is in contact.

Above the base 101, a pair of guide shafts 1 is provided.
03 are parallel to each other and are also erected and supported so as to be parallel to the base material holding surface 201d of the suction member 201. The support body 10 for attaching the squeegee 104 to the guide shaft 103
4a is mounted via a sliding member such as a slide bearing, and can be driven by a driving mechanism (not shown) such as a ball screw or an air cylinder.

As a result, the support 104a becomes the base material holding surface 2
The guide shaft 1 is applied to the base material 501 uniformly held at 01d.
03 is movable in the longitudinal direction. Support 1
04a is provided with a vertical lifting guide shaft 104b and a pressing force adjusting mechanism (not shown) such as a regulator, and a squeegee 104 is mounted on the lower end of the vertical lifting guide shaft 104b in parallel with the base material 501. . This allows the squeegee 104 to move in the vertical direction and set a predetermined pressing force.

Therefore, in the present invention, an opening is provided at the end of the squeegee 104 (outside the paste filling area, inside the plate frame), and a shear stress detector 104c is provided inside the opening. In the present embodiment, a strain gauge is used for the detection part of the shear stress detector. As a result, when the paste is rolled by the movement of the squeegee 104, the paste also enters the entire surface of the stress detector 104c provided on the squeegee 104. A flow signal of the paste causes the strain gauge to flex and deform, thereby generating a detection signal. The detection signal has a functional relationship with the deformation amount of the strain gauge. When the moving speed of the squeegee 104 is increased, the bending deformation amount of the strain gauge is also increased and the signal voltage is increased, and when the moving speed of the squeegee 104 is decreased, the strain gauge bends. The amount of deformation decreases and the signal voltage decreases.

Even when the moving speed of the squeegee 104 is constant, the amount of bending of the strain gauge increases and the signal voltage increases as the paste viscosity increases. From this,
The signal voltage of the strain gauge is a function of the product of the viscosity of the paste and the moving speed of the squeegee, that is, the shear stress. Even if the number of pastes filled in the base material increases and the paste viscosity increases, the squeegee 104 is adjusted so that the signal voltage matches the signal voltage when the paste is well filled in the vias. By adjusting the moving speed of the via, reliable and stable paste filling into the via becomes possible.

The paste filling operation on the base material with the via opening will be described in detail with reference to FIG. The base material 501 is vacuum-held and fixed to the base material holding surface 201d via the thin paper 101e, and the outer peripheral portion excluding the paste filling area is pressed by the plate frame 102. The squeegee 104 shown by the broken line is at the squeegee initial position P1 above the plate frame 102, and
02, the paste 202 is supplied to a predetermined number of base materials in a width that covers at least the filling area by using a supply means such as a dispenser. Next, as shown by the solid line, the squeegee 104 is lowered to the squeegee movement start position P2 on the plate frame 102. At this time, the squeegee 104 comes into close contact with the plate frame 102 with a predetermined pressure.

Next, when the squeegee 104 is moved in the direction in which the squeegee 104 is in close contact with the plate frame 102, the plate frame 102 is moved.
The paste 202 supplied above is scraped up, and the strain gauge constituting the shear stress detector 104c is deformed by the flow action of the paste 202, and a signal voltage due to strain is generated. The initial value of paste viscosity is 30 Pa · S
The optimum moving speed of the squeegee was 3000 mm / min, and good filling characteristics were obtained, and the signal voltage of the shear stress detector at that time was W. Then, the mirror-finished plate frame 102, the inclined portion 102a, and the base material 501 are smoothly moved while maintaining a predetermined pressing force, and further scanned to the squeegee movement end position P3.

When the squeegee 104 reaches the minute vias 502 provided on the base material 501 during movement, the paste 20
2 is sequentially pushed into the minute via 502 in combination with the vacuum suction action of the suction member 201 via the thin paper 101e. Here, the thin paper 101e is the filled paste 202
The clogging of the suction member 201 due to the above is prevented, and by adsorbing the resin component contained in the paste 202 filled in the minute vias 502, the filling rate of the copper powder is increased.

Next, the squeegee 104 rises and a scraping squeegee (not shown) descends to scrape the paste to the filling start position, and the squeegee 104 also returns to the initial position P1. Since the scraping squeegee moves on the base material 501 with a predetermined pressure, the paste 202 does not remain in the area on the base material 501 excluding the minute vias 502.

With the above steps, the paste filling process for the first substrate is completed, and when the paste is filled for the second substrate, the detection signal from the shear stress detector becomes W. A squeegee moving speed is controlled and set by a control circuit (not shown). For example, at the time of printing 30 sheets, the paste viscosity increased to 80 Pa · S due to the adhesion, permeation and volatilization of the resin component contained in the paste 202 to the substrate, but the signal voltage of the shear stress detector was detected by the squeegee control circuit. Is controlled so that it becomes W, and the squeegee 10 at that time
The moving speed of No. 4 was 1200 mm / min. in this case,
The paste viscosity increased nearly 3 times, but the paste filling was 1
It was as good as the single-sided substrate.

Further, when the number of printed sheets is 100, the resin component contained in the paste 202 further adheres to the substrate, penetrates and volatilizes further, and the paste viscosity becomes 150 Pa · S.
However, the squeegee control circuit controlled the signal voltage of the shear stress detector to be W, and the moving speed of the squeegee 104 at that time was 600 mm / min. In this case, the paste viscosity was further increased about twice, but the paste filling was good. Therefore, in each filling cycle, the viscosity of the paste is increased by controlling the moving speed of the squeegee so that the signal voltage of the shear stress detector becomes a value at which a good filling characteristic is obtained and performing the filling operation. Therefore, it is possible to stably fill the paste into the minute vias.

In the present embodiment, the signal voltage is detected by the shear stress detector every paste filling cycle of the base material,
Although the squeegee movement speed is set through the squeegee control circuit, if the viscosity of the paste fluctuates slowly, the signal voltage is detected by the stress detector at every filling cycle of several cycles, and the squeegee movement speed is detected through the squeegee control circuit. May be set.

(Embodiment 2) FIG. 5B shows a cross section of a base material in which a blind via according to Embodiment 2 is opened. In this embodiment, a base film 503a having a thickness of about 0.02 mm and a copper foil 503b having a thickness of about 0.01 mm are used.
A substrate film 503a having a thickness of about 0.02 mm was laminated on the patterned substrate, and a cover film 503c was further adhered to both surfaces thereof to be used as the substrate 503. The minute vias are irradiated with an ultraviolet laser from one surface of the cover film 503c of the base material 503, and the copper foil 5 is exposed.
A predetermined number of blind vias 504 having a hole diameter of about 0.05 mm, the bottom surface of which is 03b, were formed at predetermined positions. Further, the paste filled in the blind via 504 to form the conductor circuit in the via has the same components, compounding ratios, and viscosities as those used in the first embodiment.

Small blind via 5 with no escape path for air
In No. 04, unlike the base material 501 having a through via structure, vacuum suction using the suction member 201 via the thin paper 101e cannot be performed, so the filling operation is performed in the following three steps.

The structure of the paste filling device according to the present embodiment will be described with reference to FIGS.
FIG. 1B is a schematic view of the paste filling device according to the present embodiment. This paste filling device is a plate frame installed on a mounting table having an O-ring fitted in an O-ring groove, a guide shaft, a squeegee, a squeegee support, a squeegee drive mechanism, a squeegee control circuit, and a squeegee. Of a shear stress detector attached to the end of the or the squeegee support, a first stage composed of a vertical lifting guide shaft, and a flange installed on the mounting table, and a vertical lifting guide,
The second stage is composed of a vacuum dome provided with a vacuum exhaust port and an atmosphere opening port. A function to degas bubbles by vacuum exhausting bubbles in the paste filled in the via by installing the first stage on the mounting table when filling the paste and installing the second stage on the mounting table when defoaming. It is a paste filling device in which is added.

FIG. 3 is a cross-sectional view of an essential part of the device for removing bubbles in the paste according to the present embodiment.
The state is shown in which the opposing vacuum dome 106 is descending toward. On the mounting table 105, in order to position and mount the base material 503 at a predetermined position, the base material control frame 1 having a height of about 2 mm is placed outside by about 1 mm from the outer shape of the base material 503.
05c was provided. Further, an O-ring 105b is fitted to the O-ring groove 105a as a sealing means for the flange portion 106a of the vacuum dome 106 on the mounting table upper surface 105d,
The contact surfaces of the O-ring groove 105a and the flange portion 106a with the O-ring 105b are mirror-finished by buffing to improve the adhesion.

The vacuum dome 106 faces the mounting table upper surface 105d, and a pair of vacuum dome lifting guide shafts 106b.
Is vertically guided by an elevating guide 106e and can be moved up and down by a driving means (not shown) such as an air cylinder. The flange 106a is provided so as to project outward along the outer periphery of the lower end of the vacuum dome 106, and is integrated with the vacuum dome 106 by welding with good airtightness. The inside of the vacuum dome 106 does not interfere with the base material regulating frame 105c provided on the mounting table 105 and has a minimum volume.

Further, the vacuum exhaust port 106c is connected to the vacuum dome 1.
It is provided so as to communicate with the inside of 06, and is connected to an external vacuum source (not shown) such as a vacuum pump via a vacuum pressure regulator (not shown). Further, an atmosphere opening port 106d is provided so as to communicate with the inside of the vacuum dome 106, and communicates with the atmosphere through an opening / closing valve (not shown) linked to a detector (not shown) that detects the pressure inside the vacuum dome. is doing.

As a result, when the vacuum dome 106 is lowered and the flange 106a is in contact with the O-ring 105b to obtain sufficient contact, the vacuum exhaust port 106c evacuates the vacuum dome 106 in a short time. It is possible to reach a predetermined vacuum pressure inside the dome 106, and a predetermined pressure degree is reached by opening a switching valve by detecting a signal when the vacuum pressure detector provided in the vacuum exhaust port 106c reaches a predetermined vacuum degree. At the same time, it enables rapid air release.

Next, a method of filling the blind vias with the paste according to the present embodiment will be described. First, in the first step, the first stage similar to that of the first embodiment is used, the base material 503 is held in close contact, and the paste 202 supplied to the front side in the traveling direction of the squeegee is detected by the shear stress detector. In advance, the fine blind vias 504 are filled with the paste 202 by appropriately controlling the moving speed of the squeegee so as to be the same as the signal voltage value showing the good filling characteristic in advance.

However, in the minute blind via 504 having no escape path for air, unlike the base material 501 having the through via structure, the suction member 201 cannot be vacuum-sucked through the thin paper 101e, and therefore the paste 202 is not filled. Bubbles remain when the paste 202 is pushed in with a squeegee on the bottom surface of the fine blind via 504 which is complete and particularly. Such a state is repeatedly performed in the paste filling region of the base material 503, and the paste 202 is in an incomplete filling state for all the small blind vias 504. FIG. 3 shows a state in which the base material 503 pre-filled with paste is placed at a position regulated by the base material regulating frame 105c provided on the mounting table 105.

In the second step, the vacuum dome 106
Was lowered to bring the flange 106a into contact with the O-ring 105b, and the inside of the vacuum dome 106 was depressurized by performing vacuum exhaust from the vacuum exhaust port 106c. Here, the bubbles remaining in the small blind vias 504 are the vacuum bubbles dome 106.
As the inside pressure is reduced, the bubbles are discharged from the inside of the minute blind via 504 by the defoaming action. Since the entire substrate 503 is inside the vacuum dome 106, the defoaming of the substrate 503 acts on the entire paste filled in all the blind vias 504 provided on the substrate 503 and simultaneously. Since the volume of bubbles remaining in the small blind vias 504 is minute and the internal volume of the vacuum dome 106 is also small, the depressurization is completed in a short time, and the bubbles in the paste can be defoamed in a short time.

When the paste 202 filled in the small blind vias 504 is opened to the atmosphere, the bubbles remaining on the bottom surface are removed by the defoaming action, and due to atmospheric pressure, the copper foil on the bottom surface of the small blind vias 504 is removed. Although the connection with 503b is complete, the paste surface on the upper surface of the blind via is recessed by an amount corresponding to the bubble volume.

Next, in the third step, the air bubble-defoamed substrate 503 of the minute blind via 504 is again
In the same first stage as in the first embodiment, a portion of the upper surface of the blind via where the paste surface is recessed is refilled by repeating the initial paste filling procedure. As a result, the paste 202 is completely filled without bubbles remaining in the minute blind vias.

The present invention is not limited to the above embodiment, and the same effect can be obtained even if the configuration is changed as follows.

(A) Although the embodiment has been described in which the paste is filled in the minute vias provided in the base material, the paste filling method of the present invention can be applied to the printing and filling of the paste using a screen mask, a metal mask or the like. .

(B) The squeegee movement is not limited to one direction, and the squeegee movement may be one or more round trips.

(C) In the second embodiment, the vacuum dome moves up and down, but the mounting table may move up and down.

(D) The base material is not limited to a divided material, and a roll sheet-shaped base material may be used, and the device can be continuously filled by adding the functions of a supply section and a winding section. .

(E) The base material is not limited to the one used in this embodiment, but can be applied to a ceramic green sheet or the like.

[0054]

As is apparent from the above description, according to the present invention, it is possible to surely fill the fine vias or the fine blind vias provided in the base material with the paste, reduce the amount of the paste used, and have excellent productivity. It is possible to provide a paste filling method and a paste filling device. It is extremely effective in the manufacturing process of a high-density wiring board, and its industrial effect is great.

[Brief description of drawings]

1A is a schematic diagram of a paste filling device according to a first embodiment of the present invention, and FIG. 1B is a schematic diagram of a paste filling device according to a second embodiment of the present invention.

FIG. 2 is a sectional view of the paste filling device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of an essential part of a device for removing bubbles in a paste according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a paste filling operation according to the first embodiment of the present invention.

FIG. 5 (a) is a cross-sectional view of a base material with microscopic vias used in the present invention. (B) is a cross-sectional view of a base material with microscopic blind vias used in the present invention.

FIG. 6 is a diagram showing a paste filling device by a paste filling method according to a first conventional example.

FIG. 7 is a diagram showing a paste filling device by a paste filling method according to a second conventional example.

[Explanation of symbols]

101 base 102 plate frame 103 guide shaft 104 Squeegee 104c Shear stress detector 105 mounting table 106 vacuum dome

Continued front page    (72) Inventor Takeshi Suzuki             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5E317 AA24 BB01 BB12 CC23 CC25                       CD32 CD36 GG14 GG16                 5E346 AA43 CC02 CC08 CC32 DD02                       DD32 FF18 GG15 GG19 GG31                       HH07 HH33

Claims (10)

[Claims] 1. When filling a microscopic via provided in a base material with a conductive paste, the product of the viscosity and the squeegee moving speed of the conductive paste supplied forward of the squeegee with respect to the base material is kept constant. A conductive paste filling method for a minute via is characterized by controlling the moving speed of the squeegee. 2. When filling a microscopic via provided in a base material with a conductive paste, the back surface side of the base material is held in close contact,
A squeegee is closely arranged on the surface side of the base material, a conductive paste is supplied to the front side in the moving direction of the squeegee, shear stress is detected by a shear stress detector attached to the end of the squeegee, and a constant shear stress is obtained. The conductive paste filling method according to claim 1, wherein the moving speed of the squeegee is controlled so as to achieve the above. 3. The conductive paste filling method according to claim 2, wherein the shear stress is detected by a shear stress detector having a strain gauge as a detecting portion. 4. The moving speed of the squeegee is controlled so that the detected value of the shear stress detector is the value of the shear stress when the best filling state obtained in advance by experiment is shown. The conductive paste filling method according to claim 2. 5. A base for holding and fixing a base material provided with micro vias, and a plate frame abutting on an outer peripheral portion of the base material placed on an upper surface of the base, excluding a paste filling area. A squeegee that fills the minute vias with a paste supplied by moving relative to the base material, a squeegee drive mechanism, a squeegee control circuit, and a shear stress detector for detecting shear stress, A paste filling device, wherein the moving speed of the squeegee is controlled so that the shear stress is constant. 6. The paste filling device according to claim 5, wherein the shear stress detector is attached to an end of the squeegee. 7. The paste filling device according to claim 5, wherein the shear stress detector is attached to a lifting shaft of the squeegee. 8. A squeegee which controls a squeegee driving circuit so that a detected value obtained by a shear stress detector matches a value of shear stress when the best filling state is shown as a result of an experiment conducted in advance. The conductive paste filling device according to claim 5, further comprising a control circuit. 9. A method of filling a conductive paste into a fine blind via provided on a base material, wherein the conductive paste is filled into the fine blind via according to the method of claim 2, and then the base is formed. The material is put in a predetermined vacuum dome to degas bubbles in the fine blind vias and the conductive paste, and then the atmosphere is opened, and the fine blind vias are filled with the paste by the method according to claim 2. And a method for filling a conductive paste. 10. A plate frame, a guide shaft, and a squeegee installed on a mounting table having an O-ring fitted in an O-ring groove.
A squeegee support, a squeegee drive mechanism, a squeegee control circuit, a shear stress detector attached to an end of the squeegee or the squeegee support, a first stage including a vertical lifting guide shaft, and the mounting table described above. The second stage is composed of a vacuum dome having an upper flange, an up-and-down lifting guide, a vacuum exhaust port, and an atmosphere opening port, and the first stage is placed on the mounting table when the paste is filled. 9. The conductive paste according to claim 8, further comprising a function of degassing by evacuation of bubbles in the paste filled in the via by installing the second stage on the mounting table when defoaming. Filling device.