Aspects of the present disclosure relate to dispersing graphene oxide in a fluid and washing a first electronic part with cleaning fluid. Aspects of the present disclosure relate to testing cleaning fluid for a concentration of ions, and determining whether the ion concentration is below a threshold. If the ion concentration is below a threshold level, continuing to wash parts with the fluid. If the ion concentration is above a threshold level, replacing the cleaning fluid.

Aspects of the present disclosure relate to dispersing graphene oxide in a fluid and washing a first electronic part with cleaning fluid. Aspects of the present disclosure relate to testing cleaning fluid for a concentration of ions, and determining whether the ion concentration is below a threshold. If the ion concentration is below a threshold level, continuing to wash parts with the fluid. If the ion concentration is above a threshold level, replacing the cleaning fluid.

A printed circuit board includes: a first insulating layer; a first circuit layer disposed on one surface of the first insulating layer; a second insulating layer disposed on the first insulating layer and covering at least a portion of the first circuit layer; a via conductor passing through the second insulating layer and connected to the first circuit layer; a via land connected to the via conductor in an upper portion of the via conductor; and a second circuit layer disposed on the second insulating layer and connected to the via land. The via conductor and the via land have a first interface where the via conductor and the via land are in contact with each other.

According to the embodiment, in a method for manufacturing a ceramic circuit board in which a copper plate is bonded to at least one surface of a ceramic substrate via a brazing material layer, the brazing material layer does not include Ag, but includes Cu, Ti, and one or two of Sn or In, and a ceramic circuit board is prepared in which a portion of the brazing material layer is exposed between the patterned configuration of the copper plate. The method includes a chemical polishing process of chemically polishing the portion of the brazing material layer, and a brazing material etching process of etching the chemically polished portion of the brazing material layer by using an etchant that includes one or two selected from hydrogen peroxide and ammonium peroxodisulfate and has a pH of not more than 6.

According to the embodiment, in a method for manufacturing a ceramic circuit board in which a copper plate is bonded to at least one surface of a ceramic substrate via a brazing material layer, the brazing material layer does not include Ag, but includes Cu, Ti, and one or two of Sn or In, and a ceramic circuit board is prepared in which a portion of the brazing material layer is exposed between the patterned configuration of the copper plate. The method includes a chemical polishing process of chemically polishing the portion of the brazing material layer, and a brazing material etching process of etching the chemically polished portion of the brazing material layer by using an etchant that includes one or two selected from hydrogen peroxide and ammonium peroxodisulfate and has a pH of not more than 6.

A method for manufacturing a water resistant substrate comprises a first step of providing a substrate. The method proceeds with a step of populating at least one component onto the substrate. Next, the method includes a step of cleaning the substrate including the at least one component to form a cleaned substrate. Then, the method proceeds with depositing a multi-layered water resistant coating onto the cleaned substrate.

Disclosed herein are solvent compositions and methods of using the solvent compositions. The solvent composition includes at least trans-1,2-dichloroethylene (t-DCE) and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TFE-TFPE). The solvent composition may also include an oxygenated solvent, such as an alcohol or fluorinated ether. A method of cleaning the surface of an article includes contacting the surface with the solvent composition to dissolve, disperse, or displace a contaminant on the surface, and removing the solvent composition containing the contaminant from the surface.

Disclosed herein are solvent compositions and methods of using the solvent compositions. The solvent composition includes at least trans-1,2-dichloroethylene (t-DCE) and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TFE-TFPE). The solvent composition may also include an oxygenated solvent, such as an alcohol or fluorinated ether. A method of cleaning the surface of an article includes contacting the surface with the solvent composition to dissolve, disperse, or displace a contaminant on the surface, and removing the solvent composition containing the contaminant from the surface.

According to one embodiment, a method for manufacturing a ceramic circuit board is disclosed. The ceramic circuit board includes a copper plate bonded to at least one surface of a ceramic substrate via a brazing material layer including Ag, Cu, and a reactive metal. The method includes: preparing a ceramic circuit board in which a copper plate is bonded on a ceramic substrate via a brazing material layer, and a portion of the brazing material layer is exposed between a pattern shape of the copper plate; a first chemical polishing process of chemically polishing the portion of the brazing material layer; and a first brazing material etching process of etching the chemically polished portion of the brazing material layer by using an etchant having a pH of 6 or less and including one type or two types selected from hydrogen peroxide and ammonium peroxodisulfate.

According to one embodiment, a method for manufacturing a ceramic circuit board is disclosed. The ceramic circuit board includes a copper plate bonded to at least one surface of a ceramic substrate via a brazing material layer including Ag, Cu, and a reactive metal. The method includes: preparing a ceramic circuit board in which a copper plate is bonded on a ceramic substrate via a brazing material layer, and a portion of the brazing material layer is exposed between a pattern shape of the copper plate; a first chemical polishing process of chemically polishing the portion of the brazing material layer; and a first brazing material etching process of etching the chemically polished portion of the brazing material layer by using an etchant having a pH of 6 or less and including one type or two types selected from hydrogen peroxide and ammonium peroxodisulfate.