Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Coating moving substrate
Reexamination Certificate
1999-12-27
2003-05-13
Nguyen, Nam (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Coating moving substrate
C204S201000, C204S212000, C204S213000, C204S272000, C204S273000, C204S275100, C205S144000, C205S145000, C205S149000
Reexamination Certificate
active
06562217
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a manufacturing method of conductive fine particles which are free from aggregation in a plating solution and which forms a plating layer having a extremely uniform thickness, the manufacturing device thereof, the conductive fine particles as well as an anisotropic conductive adhesive and a conductive connecting structural element using such particles.
The present invention further concerns an electronic circuit part which is obtained by connecting an electronic circuit element, such as a semiconductor element, a quartz oscillator and a photoelectric transfer element that are used in the field of electronics, and an electronic circuit substrate through conductive fine particles in a manner so as to be connected to fine electrodes, an electronic circuit element, an electronic circuit substrate and conductive fine particles used in such an electronic circuit part, as well as a manufacturing method for such an electronic circuit part.
BACKGROUND OF THE INVENTION
Conductive materials include conductive paste, conductive adhesives, anisotropic conductive films, etc., and for this conductive material, a conductive composition comprising conductive fine particles and a resin is used. With respect to the conductive fine particles, there are generally used metal powder, carbon powder, fine particles having a metal plating layer on the surface, etc.
Manufacturing methods for such conductive fine particles having a metal plating layer on the surface are disclosed by for example, the following Japanese Kokai Applications: Sho-52-147797, Sho-61-277104, Sho-61-277105, Sho-62-185749, Sho-63-190204, Hei-1-225776, Hei-1-247501 and Hei-4-147513.
Among these manufacturing methods, when carrying out plating on fine particles having a particle size of not less than 5000 &mgr;m, barrel plating devices are generally used. In the barrel plating device, a plating target is put inside a rotatable barrel having a polygon cylinder shape in which a plating solution is contained, and while the barrel is being rotated, electroplating is carried out by allowing the plating target to contact the cathode placed inside the barrel.
However, when plating is carried out on fine particles having a particle size not more than 5000 &mgr;m by a method using the barrel plating device, problems arise in it that fine particles in an aggregated state are subjected to plating in the plating solution, failing to form mono-particles and in it that particles are not plated uniformly, causing an irregular plating layer.
In order to solve these problems, for example, the following plating devices have been proposed: Japanese Kokai Publication Hei-7-118896 discloses a manufacturing device for conductive fine particles which comprises a disk-shaped bottom plate secured to the upper end of a perpendicular driving shaft, a contact ring for conducting electricity placed on the upper face of the porous member, a porous member that is placed in the vicinity of the contact ring and that allows only a plating solution to pass there through, a hollow cover of a trapezoidal cone shape having an opening on its upper center portion, a treatment chamber formed in a manner so as to sandwich the contact ring between the outer circumferential portion of the hollow cover and the bottom plate, a supply tube for supplying the plating solution to the treatment chamber through the opening, a container for receiving plating solution scattered from the pores of the porous member, a drain tube for draining the plating solution accumulated in the container, and an electrode inserted through the opening to contact the plating solution, wherein, during the plating process, rotation and stoppage or speed reduction are repeated.
Japanese Kokai Publication Hei-8-239799 discloses a manufacturing device for conductive fine particles, in which the contact ring and the porous member are integrally connected.
Japanese Kokai Publication Hei-9-137289 discloses a manufacturing method for conductive fine particles, wherein a plating device, comprising a rotatable plating device main body having a filter section formed on at least one portion of its outer circumferential section and a cathode as a contact ring formed on the outer circumferential section and an anode placed inside the main body so as not to contact the cathode, is used for forming a plating layer on the surface of the fine particles put inside the main body, while the main body is rotated centered on its rotation axis and the plating solution is supplied to inside of the main body.
In these manufacturing devices for conductive fine particles, a plating target is pressed onto the contact ring by a centrifugal force, and rotated, and stopped or reduced in the speed repeatedly, therefore, the conductivity is improved even in the uniformly mixed state, the current density is increased, and the update of the plating solution is frequently carried out so that the fine particles are free from aggregation in the plating solution, thereby making it possible to obtain conductive fine particles having a plating layer with a uniform thickness.
However, the following problems arise in these manufacturing devices for conductive fine particles.
The pore size of the porous member and the number of revolutions (peripheral velocity) of the treatment chamber are appropriately selected in accordance with the particle size of fine particles as plating targets. In the case when fine particles having a particle size of not more than 100 &mgr;m are subjected to plating, it is necessary to increase the peripheral velocity of the treatment chamber so as to make the particles contact the contact ring. For example, in the case of fine particles having a diameter in the range of 60 to 100 &mgr;m, the pore size of the porous member needs to be set to not less than 20 &mgr;m and the peripheral velocity needs to be set to not less than 300 m/min. It is confirmed that the peripheral velocity not more than this value is hard to allow the fine particles to contact the cathode (contact ring) and plating deposition is sometimes not carried out.
However, when the peripheral velocity of the treatment chamber is increased, the plating solution is subject to a force in the outer circumferential direction by the function of a centrifugal force so that the plating solution forms a vortex having a mortar-like shape inside the treatment chamber, gradually rises along the inner wall of the hollow cover, and is scattered from the opening of the hollow cover. As a result, the problem arises in it that the fine particles flow out (overflow) from the treatment chamber together with the scattered plating solution. In addition, if the amount of the liquid within the treatment chamber is reduced so as to prevent the overflow, the area in which the electrode in contact with the plating solution is reduced, with the result that the current density is reduced and further the formation of a vortex causes the electrode to be exposed, resulting in no contact with the plating solution and no current flow.
Because of these problems, it have been impossible to actually carry out plating on fine particles of not more than 100 &mgr;m.
Moreover, with respect to the pore size of the porous member, those pore sizes not allowing a plating solution to pass there through have been adopted, and several kinds of porous members have been used in accordance with the particle size of the fine particles.
However, since these porous members are filter-shaped porous members made of plastics or ceramics having communicating bubbles, the pore sizes within the porous members have considerably much variation. For this reason, at portions where the pore sizes of the porous members are the same as or greater than the particle size of the fine particles, clogging and particle losses occur at the time of passage of the particles. Moreover, when a porous member of not more than 20 &mgr;m is used, the resistance at the time of the passage of the plating solution through the porous member becomes greater, as a result that the amount
Kanki Kazuhiko
Kodera Yoshiaki
Matsubara Manabu
Suzuki Tatsuo
Tanaka Yoshiaki
Connolly Bove & Lodge & Hutz LLP
Leader William T.
Nguyen Nam
Sekisui Chemical Co. Ltd.
LandOfFree
Method and device for manufacturing conductive particles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for manufacturing conductive particles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for manufacturing conductive particles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3003261