Method for manufacturing ceramic circuit board
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.
1 . A method for manufacturing a ceramic circuit board, the method comprising:
a process of preparing a bonded body in which a copper member is bonded to at least one surface of a ceramic substrate via a brazing material layer, the brazing material layer not including Ag, the brazing material layer including Cu, an active metal, and a first element, the first element being at least one selected from Sn and In;
a first copper etching process of etching a portion of the copper member and a layer included in the brazing material layer by using at least one of iron chloride or copper chloride in the first copper etching process to expose a part of an active metal reaction layer included in the brazing material layer, the layer included in the brazing material layer including Cu and the first element as major components;
a first brazing material etching process of etching the exposed part of the active metal reaction layer by using an etchant including one or two selected from hydrogen peroxide and ammonium peroxodisulfate, the etchant having a pH of not less than 4 and not more than 6, a jutting portion of the brazing material layer that juts from the copper member being formed, the jutting portion including a precipitate that includes Cu; and
a first chemical polishing process of chemically polishing the jutting portion, a chemical polishing liquid including sulfuric acid or hydrochloric acid being used to remove the precipitate,
wherein a length of the jutting portion after the first chemical polishing process is not less than 10 μm and not more than 200 μm.
2 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a length of a long side of the ceramic substrate is not less than 100 mm.
3 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a length of a long side of the ceramic substrate is not less than 200 mm.
4 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
there is a location at which a distance between the etched copper members is not more than 2 mm.
5 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
the etchant further includes ammonium fluoride and a pH-stabilizing agent.
6 . The method for manufacturing the ceramic circuit board according to claim 5 , wherein
the pH-stabilizing agent is at least one selected from HBF 4 , EDTA, NTA, CyDTA, DTPA, TTHA, GEDTA, glycine, dicarboxylic acid, tricarboxylic acid, oxycarboxylic acid, and their salts.
7 . The method for manufacturing the ceramic circuit board according to claim 1 , further comprising:
a cleaning process of cleaning the bonded body after the first brazing material etching process and the first chemical polishing process.
8 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
the ceramic substrate is a nitride ceramic substrate.
9 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
the first copper etching process includes coating an etching resist on the copper member, and subsequently patterning the copper member into a patterned configuration by etching the portion of the copper member.
10 . The method for manufacturing the ceramic circuit board according to claim 9 , wherein
the first brazing material etching process is performed on the bonded body from which the etching resist is removed after the copper member is etched.
11 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
the first brazing material etching process is performed while applying an ultrasonic wave to the bonded body.
12 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a second copper etching process of etching the copper member is performed after the first chemical polishing process.
13 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a cleaning process in which a flow rate of a cleaning water is not less than 1.3 L (liter)/minute is performed as a finishing cleaning process.
14 . The method for manufacturing the ceramic circuit board according to claim 13 , wherein
a drying process after the finishing cleaning process is performed using air within a range of not less than 20 m/s and not more than 150 m/s and with a humidity of not more than 70%.
15 . The method for manufacturing the ceramic circuit board according to claim 1 , further comprising:
a cleaning process of cleaning the bonded body after the first brazing material etching process and the first chemical polishing process.
16 . The method for manufacturing the ceramic circuit board according to claim 15 , wherein
a cleaning process in which a flow rate of a cleaning water is not less than 1.3 L (liter)/minute is performed as a finishing cleaning process.
17 . The method for manufacturing the ceramic circuit board according to claim 16 , wherein
a drying process after the finishing cleaning process is performed using air within a range of not less than 20 m/s and not more than 150 m/s and with a humidity of not more than 70%.
18 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a cleaning process of cleaning the bonded body by spraying water from a nozzle is performed as a finishing cleaning process, and
in the cleaning process, a distance between the nozzle and the bonded body is set within a range not less than 5 cm and not more than 40 cm.
19 . The method for manufacturing the ceramic circuit board according to claim 1 , wherein
a cleaning process of cleaning the bonded body by spraying water from a nozzle is performed as a finishing cleaning process, and
in the cleaning process, a water amount that impacts the bonded body per nozzle is within a range of not less than 0.01 L/(minute·cm 2 ) and not more than 0.1 L/(minute·cm 2 ).