Fluent material handling – with receiver or receiver coacting mea – Plural filling means
Reexamination Certificate
2002-10-09
2004-02-24
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Plural filling means
C141S004000, C141S065000, C141S125000, C141S280000
Reexamination Certificate
active
06695020
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a fluid material filling apparatus and a fluid material filling method which is capably of stuffing a fluid material not only into a through hole or a shallow closed-end bore but also into a specific closed-end bore having a very small size in diameter and/or depth.
Conventionally, a printed circuit board is provided with via holes formed in an insulating substrate body thereof. A screen printing method is generally used to fill the via holes with a conductive paste serving as a fluid material.
According to a conventional screen printing method for filling the via holes with a conductive paste, a first step is preparing a screen plate with penetration apertures located at predetermined portions corresponding to via holes to be formed. In the next step, the screen plate is placed on the insulating substrate body. Then, the conductive paste is supplied onto the screen plate. Then, the conductive paste on the screen plate is moved or wiped from one end to the other end along a screen surface under the condition that the screen plate is pushed by a squeegee. Thus, under the pressure given by the squeegee, the conductive paste penetrates the penetration apertures and enters into the via holes.
According to the above-described conventional method, it is possible to forcibly push the paste material into a through hole. However, this conventional method is not preferably applicable to via holes with bottoms. For example, when a wiring pattern pad is placed at the bottom of a substrate, via holes opened across the substrate body necessarily have bottoms. In such a case, the residual air in the bottom of each via hole cannot be smoothly replaced by the paste material. Accordingly, undesirable voids of residual air will remain in the bottom of respective via holes. This problem will be severe when the mounting density of electronic elements on a printed circuit board is increased and when the diameter of respective via holes becomes small or when the depth of respective via holes becomes deep.
SUMMARY OF THE INVENTION
In view of the above-described problems, the present invention has an object to provide a fluid material filling apparatus and a fluid material filling method which are capable of sufficiently filling a closed-end hole with a fluid material, and especially capable of supplying the fluid material deeply into the bottom of respective holes formed in a substrate.
In order to accomplish the above and other related objects, the present invention provides a first filling apparatus for filling a hole of a substrate with a fluid material, comprising a scavenging section for forming a first hermetically closed chamber when brought into contact with a substrate surface and for depressurizing the first hermetically closed chamber, a fluid material filling section for forming a second hermetically closed chamber when brought into contact with the substrate surface and for stuffing the fluid material into the hole of the substrate within the second hermetically closed chamber, and shifting means for shifting the second hermetically closed chamber of the fluid material filling section to a position of the hole of the substrate after the hole of the substrate is depressurized in the first hermetically closed chamber of the scavenging section. The second hermetically closed chamber is provided adjacent to the first hermetically closed chamber. The fluid material filling section comprises a supply section for supplying the fluid material onto a substrate surface within the second hermetically closed chamber and a squeezing unit for pushing the fluid material into the hole of the substrate within the second hermetically closed chamber.
According to the above-described first fluid material filling apparatus, the scavenging section depressurizes the first hermetically closed chamber so that the air or gas in the hole positioned in the first hermetically closed chamber is scavenged. Then, the second hermetically closed chamber of the fluid material filling section shifts on the substrate surface so as to arrive on the hole thus depressurized. In this condition, the fluid material filling section pushes the fluid material into the depressurized hole. In this case, as the air or gas in the hole is sufficiently scavenged beforehand, the fluid material surely enters into the hole. The inside space of the hole can be entirely filled with the fluid material.
According to the first fluid material filling apparatus, it is preferable that the squeezing unit causes a motion selected from the group consisting of a rotational motion, an orbital motion, and a swing motion in the second hermetically closed chamber. The rotating or swinging squeezing unit is effective to push the fluid material from different directions. Thus, it becomes possible to surely fill the hole with the fluid material.
According to the first fluid material filling apparatus, it is preferable that the squeezing unit includes a sliding member which slides on the substrate surface. The sliding member can wipe the fluid member supplied on the substrate surface and convey the collected fluid material into the hole.
According to the first fluid material filling apparatus, it is preferable that the sliding member is constituted by a rectangular elastic body inclined with respect to the substrate surface. Positioning the sliding member in an inclined relationship with the substrate surface makes it possible to produce a force for pushing the fluid material into the hole at the given angle. The hole can be sufficiently filled with the fluid material. When the sliding member is made by an elastic body having spilt rectangular portions, each rectangular elastic piece can flexibly respond to the rotation or shifting directional change of the squeezing unit and also can follow the undulation of the substrate surface. The contact between the sliding member and the substrate surface can be appropriately maintained. Accordingly, the sliding member can effectively capture the fluid material supplied on the substrate surface at higher probabilities. Thus, the hole can be surely filled with the fluid material.
According to the first fluid material filling apparatus, it is preferable that the supply section holds the fluid material at a predetermined upper position above the squeezing unit within the second hermetically closed chamber, and supplies the fluid material onto the substrate surface via a clearance between a side wall of the second hermetically closed chamber and the squeezing unit. This arrangement requires no special mechanism for supplying the fluid material because the fluid material surely flows down onto the substrate surface from the upper position above the squeezing unit. Furthermore, when the squeezing unit causes a rotational motion, the rotational movement of the squeezing unit can promote the flow of the fluid material directed toward the substrate surface. In this respect, rotating the squeezing unit is preferable. Especially, when the squeezing unit causes an orbital motion in the second hermetically closed chamber, the clearance between the squeezing unit and the second hermetically closed chamber increases or decreases cyclically. This cyclic change of the clearance between the squeezing unit and the second hermetically closed chamber can produce a pump function for surely moving or pushing the fluid material.
According to the first fluid material filling apparatus, it is preferable that the fluid material filling apparatus further includes a depressurizing device for depressurizing the second hermetically closed chamber. If a significant amount of air or gas remains in the second hermetically closed chamber, the residual air or gas and the fluid material will flow into the hole depressurized in the first hermetically closed chamber at the moment the depressurized hole relocates into the second hermetically closed chamber. This will result in an undesirable filling operation of the fluid material.
According to the first fluid material filling apparatus, it is preferable t
Sakaida Atushi
Taniguchi Toshihisa
Denso Corporation
Douglas Steven O.
Harness Dickey & Pierce PLC
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