Metal fusion bonding – Process – Using bond inhibiting separating material
Utility Patent
1998-09-03
2001-01-02
Ryan, Patrick (Department: 1725)
Metal fusion bonding
Process
Using bond inhibiting separating material
C228S180210, C228S214000, C228S219000, C228S223000
Utility Patent
active
06168068
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled a Methodfor Preventing a Gold Plate Connector on a Pcb from Being Contaminated earlier filed in the Korean Industrial Property Office on the 3
rd
day of September 1997, and there duly assigned Ser. No. 45583/1997, a copy of which is annexed hereto.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a method of preventing contamination of a connector on a printed circuit board, and more particularly to a method of preventing a gold plate connector on a printed circuit board from being contaminated during a soldering process using wave soldering.
2. Related Art
Generally, various electronic components are mounted on a printed circuit board (PCB). Those electronic components are classified as surface mount technology (SMT) components which are directly soldered to a copper-coated pad on a surface of a substrate and also classified as pin-through-hole components or printed board assembly (PBA) components which are soldered after being inserted into a copper-coated hole of the substrate, according to the method of mounting the electronic components on the printed circuit board. Those components are soldered through different soldering methods and then mounted on the printed circuit board.
Here, as soldering methods for printed board assembly (PBA) components, there is a wave soldering method which also called a flow soldering process. The wave soldering is a method of soldering the printed board assembly components which are inserted in the copper-coated hole by dipping the printed circuit board in a bath where a melted liquid lead is contained.
A gold electrical connector coupled with a printed circuit board can become contaminated with lead, flux, and floating gas particles during a wave soldering process. The gold electrical connector can sometimes be washed after the wave soldering process. However, the washing operations are generally complicated and inconvenient and require much time and effort. In addition, the washing causes an economic burden due to the preparation of washing apparatuses thereof. Most of all, much more time is required to perform the entire process due to the additional operation of washing the gold plate connector, and the efficiency of soldering the printed circuit board is thereby curtailed. The aforementioned problems are caused by the contamination of the gold plate connector.
Exemplars of recent efforts in the art include U.S. Ser. No. 08/881,566 for Apparatus to Clean Golden Plates invented by Woo-Sig KIM, et al., U.S. Pat. No. 5,728,431 for a Processfor Forming Self-assembled Polymer Layers on a Metal Surface issued to Bergbreiter et al., U.S. Pat. No. 5,672,394 for Electrodes of Improved Service Life issued to Hardee et al., U.S. Pat. No. 5,650,088 for a Treating Solution for Gold-plated Material issued to Kodama, U.S. Pat. No. 5,350,323 for a Contactfor an Electrical Connector Protected by a Polymer Film and its Production Process issued to Boissel et al., U.S. Pat. No. 5,190,486 for Selectively Plating Electrically Conductive Pin issued to Tsuk, U.S. Pat. No. 4,004,042 for a Method for Applying a Wear and Impact Resistant Coating issued to Fairbaim, and U.S. Pat. No. 3,948,736 for a Method of Selective Electroplating and Products Produced Thereby issued to Russell.
While these recent efforts provide advantages, I note that they fail to adequately provide an efficient method for preventing a gold plate connector on a printed circuit board from being contaminated.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to prevent the adhesion of a lead to a gold plate connector during a soldering process and prevent the permeation of a flux and the contamination of the gold plate connector caused by floating gas particles generated in the case of wave soldering, so that a troublesome and inconvenient operation of washing the gold plate connector cannot be performed.
According to one aspect of the present invention, the soldering process for performing the wave soldering on a printed circuit board (PCB) after spreading flux over the printed circuit board on which electronic components are mounted, includes the steps of: forming a strip mask in form of a membrane by solidifying a masking solution after spreading the masking solution capable of being solidified over the gold plate connector of the printed circuit board, before spreading the flux; and removing the strip mask from the gold plate connector, after performing the wave soldering. Preferably, the masking solution is made of a vinyl-based material.
Selectively, at step of forming the strip mask, in order to facilitate the solidification of the masking solution, the printed circuit board is dried at a predetermined temperature in a predetermined time after spreading the masking solution. Generally, the predetermined temperature is 150 degrees Celsius (150° C.) to 180 degrees Celsius (180° C.). It is proper to set the predetermined time as two to three minutes. Especially, it is applied in the case of using the masking solution made of the vinyl-based material.
In the soldering process using the wave soldering according to the present invention, when the masking solution is spread over the gold plate connector of the printed circuit board before spreading the flux and then it is solidified, the strip mask in form of a membrane is produced at the gold plate connector. At this time, since the gold plate connector is protected by the strip mask, the lead is not adhered and the flux is not permeated. Moreover, the gold plate connector is not contaminated by the floating gas particles.
The strip mask formed at the gold plate connector by spreading and solidifying the masking solution is easily stripped from the gold plate connector after finishing the wave soldering. In addition, in the case that the strip mask is stripped from the gold plate connector, there are no remainders on the gold plate connector, and thereby a separate washing operation for the gold plate connector is not required.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method preventing a surface from being contaminated, comprising the steps of: forming a membrane on a first plurality of electrical terminals coupled to a printed circuit board; applying flux to a second plurality of electrical terminals adjacent to said printed circuit board, said membrane preventing said flux from contacting said first plurality of terminals; applying a heated liquid solder to said second plurality of electrical terminals, said membrane preventing said liquid solder from contacting said first plurality of electrical terminals, and said membrane preventing gaseous particles from contacting said first plurality of electrical terminals; and removing said membrane from said first plurality of electrical terminals.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method preventing a surface from being contaminated, comprising the steps of: applying a first substance to a first plurality of electrical terminals coupled to a printed circuit board, said first substance forming a membrane on said first plurality of electrical terminals; applying a second substance to a second plurality of electrical terminals adjacent to said printed circuit board, said second substance cleaning said second plurality of electrical terminals and promoting a coupling of said second plurality of electrical terminals to said printed circuit board, said membrane preventing said second substance from permeating into said first plurality of terminals; applying a third substance to said second plurality of electrical terminals to perform said coupling of said second plurality of electrical terminals to said printed circuit board, said memb
Kim Choul-su
Lee Gun-Yong
Tsukue Masaharu
Bushnell , Esq. Robert E.
Pittman Zidia T.
Ryan Patrick
Samsung Electronic Co, Ltd.
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