Printed wiring board and method for manufacturing printed wiring board

A method for manufacturing a single-sided or double-sided printed wiring board comprising a circuit layer in which a first circuit and a second circuit having different thicknesses coexist in a same reference plane, characterized by comprising the following step 1-a to step 1-e:

• step 1-a:
• a laminating step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and the clad composite material is bonded to a base material constituting an insulating layer to form a metal-clad laminate;
• step 1-b:
• a first copper etching step wherein an etching resist layer is formed on the first copper layer located on an outer layer of the metal-clad laminate, and a circuit pattern for etching is exposed and developed to etch the first copper layer located on the outer layer into a desired circuit pattern with a copper selective etching solution, and then etching resist releasing is performed to expose the different kind of metal layer in parts where unnecessary first copper layer is removed;
• step 1-c:
• a first different kind of metal etching step wherein after the first copper etching step is finished, the different kind of metal layer exposed between circuits temporarily formed on the outer layer is etched away with a different kind of metal selective etching solution to form a first circuit shape;
• step 1-d:
• a second copper etching step wherein after the first different kind of metal etching step is finished, the etching resist layer is again formed only on area which is to be the first circuit, and etching is performed with the copper selective etching solution to etch away area of the first copper layer where no etching resist layer is present, so that shape of the first circuit is finished and the second circuit still having the different kind of metal layer is formed, and then etching resist releasing is performed to expose the different kind of metal layer of the second circuit;
• and further,
• step 1-e:
• a second different kind of metal layer etching step wherein only the different kind of metal layer located on a surface of the second circuit is removed with a different kind of metal selective etching solution to form final second circuit shape, so that the printed wiring board is obtained.

A method for manufacturing a single-sided or double-sided printed wiring board in which a first circuit or a second circuit having different thicknesses coexist in a same reference plane and one circuit is buried in an insulating layer, characterized by comprising the following step 2-a to step 2-d:

• step 2-a:
• a clad composite material etching step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and using the clad composite material, only the second copper layer is etched with a copper selective etching solution to form a circuit pattern for etching on one surface, so that a clad composite material with circuit pattern is obtained;
• step 2-b:
• a laminating step wherein an etched circuit pattern surface of the clad composite material with circuit pattern obtained in the clad composite material etching step is placed onto a base material surface and bonded to the base material surface to form a metal-clad laminate in which the etched pattern is buried in the insulating layer;
• step 2-c:
• a first copper etching step wherein an etching resist layer is formed on the first copper layer on an outer layer surface of the metal-clad laminate, and a circuit pattern for etching is exposed and developed to etch the first copper layer located on the outer layer into a desired circuit pattern with a copper selective etching solution, and then etching resist releasing is performed to remove unnecessary first copper layer and expose the different kind of metal layer;
• and
• step 2-d:
• a different kind of metal etching step wherein after the first copper etching step is finished, the different kind of metal layer is etched away with a different kind of metal selective etching solution to form the first circuit and the second circuit, so that the printed wiring board is obtained.

A method for manufacturing a single-sided or double-sided printed wiring board in which a first circuit or a second circuit having different thicknesses coexist in a same reference plane and one circuit is buried in an insulating layer, characterized by comprising the following step 3-a to step 3-c:

• step 3-a:
• a clad composite material etching step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and using the clad composite material, only the second copper layer is etched with a copper selective etching solution to form a circuit pattern for etching on one surface, so that a clad composite material with circuit pattern is obtained in which the different kind of metal layer exposed on the etched circuit pattern surface is removed;
• step 3-b:
• a laminating step wherein the etched circuit pattern surface of clad composite material with circuit pattern obtained in the clad composite material etching step is placed onto a base material surface and bonded to the base material surface to form a metal-clad laminate in which the etched pattern is buried in the insulating layer;
• and
• step 3-c:
• a first copper etching step wherein an etching resist layer is formed on the first copper layer located on an outer layer surface of the metal-clad laminate, and a circuit pattern for etching is exposed and developed to etch the first copper layer located on the outer layer into a desired circuit pattern with a copper selective etching solution, and then etching resist releasing is performed to simultaneously form the first circuit and the second circuit, so that the printed wiring board is obtained.

A method for manufacturing a double-sided printed wiring board in which a first circuit and a second circuit having different thicknesses coexist in a same reference plane on one surface side, characterized by comprising the following step 4-a to step 4-e:

• step 4-a:
• a laminating step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and the clad composite material and a copper foil are used to bond onto respective one surface side of a base material constituting an insulating layer to form a metal-clad laminate;
• step 4-b:
• a first copper etching step wherein etching resist layers are formed on the first copper layer of the clad composite material located on one surface side of the insulating layer and on the copper foil layer on the other surface side, and circuit pattern for etching is exposed and developed to etch the first copper layer and the copper foil located on the outer layers into desired circuit patterns with a copper selective etching solution, and then etching resist releasing is performed to remove unnecessary first copper layer and expose the different kind of metal layer in the clad composite material, and form the copper foil into a desired circuit pattern;
• step 4-c:
• a first different kind of metal etching step wherein after the first copper etching step is finished, the different kind of metal layer exposed between circuits temporarily formed on the outer layer is etched away with a different kind of metal selective etching solution to form a first circuit shape;
• step 4-d:
• a second copper etching step wherein after the first different kind of metal etching step is finished, the etching resist layer is again formed only on area which is to be the first circuit, and etching is performed with the copper selective etching solution to etch away area of the first copper layer where no etching resist layer is present, so that the second circuit still having the different kind of metal layer is formed, and then etching resist releasing is performed to expose the different kind of metal layer on the second circuit;
• and further,
• step 4-e:
• a different kind of metal layer removing step wherein only the different kind of metal layer on a surface of the second circuit is removed with the different kind of metal selective etching solution to form final second circuit shape, so that the double-sided printed wiring board is obtained.

A method for manufacturing a double-sided printed wiring board in which a first circuit and a second circuit having different thicknesses coexist in a same reference plane on one surface side, characterized by comprising the following step 5-a to step 5-d:

• step 5-a:
• a clad composite material etching step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and using the clad composite material, only the second copper layer is etched to form a circuit pattern for etching on one surface, so that a clad composite material with circuit pattern is obtained;
• step 5-b:
• a laminating step wherein the clad composite material with circuit pattern and a copper foil are used to bond onto respective one surface side of a base material constituting an insulating layer to form a metal-clad laminate;
• step 5-c:
• a first copper etching step wherein etching resist layers are formed on the first copper layer of the clad composite material located on one surface side of the insulating layer and on the copper foil layer on the other surface side, and circuit pattern for etching is exposed and developed to etch the first copper layer and the copper foil located on the outer layers into desired circuit patterns with a copper selective etching solution, and then etching resist releasing is performed to remove unnecessary first copper layer and expose the different kind of metal layer in the clad composite material, and form the copper foil into a desired circuit pattern;
• and
• step 5-d:
• a first different kind of metal etching step wherein after the first copper etching step is finished, the different kind of metal layer exposed between circuits temporarily formed on the outer layer is etched away with a different kind of metal selective etching solution to form the first circuit, the second circuit, and a copper foil circuit, so that the double-sided printed wiring board is obtained.

A method for manufacturing a multilayer printed wiring board comprising a circuit layer in which a first circuit and a second circuit having different thicknesses coexist in a same reference plane of an insulating layer located on a surface of an inner layer core material comprising an inner layer circuit, characterized by comprising the following step 6-a to step 6-e:

• step 6-a:
• laminating step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and the clad composite material is bonded to a surface of the inner layer core material via the insulating layer to form a multilayer metal-clad laminate;
• step 6-b:
• a first copper etching step wherein etching resist layers are formed on the first copper layers located on outer layers of the multilayer metal-clad laminate, and circuit pattern for etching is exposed and developed to etch the first copper layers located on the outer layers into desired circuit patterns with a copper selective etching solution, and then etching resist releasing is performed to expose the different kind of metal layer in parts where unnecessary first copper layers are removed;
• step 6-c:
• a first different kind of metal etching step wherein after the first copper etching step is finished, the different kind of metal layers exposed between circuits temporarily formed on the outer layers are etched away with a different kind of metal selective etching solution to form a first circuit shape;
• step 6-d:
• a second copper etching step wherein after the first different kind of metal etching step is finished, the etching resist layers are again formed only on area which is to be the first circuit, and etching is performed with the copper selective etching solution to etch away area of the first copper layers where no etching resist layer is present, so that the second circuit still having the different kind of metal layer is formed, and then the etching resist releasing is performed to expose the different kind of metal layer of the second circuit;
• and further,
• step 6-e:
• a different kind of metal layer removing step wherein only the different kind of metal layer on a surface of the second circuit is removed with the different kind of metal selective etching solution to form final second circuit shape, so that the printed wiring board is obtained.

A method for manufacturing a multilayer printed wiring board in which a first circuit and a second circuit having different thicknesses coexist in a same reference plane of an insulating layer located on a surface of an inner layer core material comprising an inner layer circuit, characterized by comprising the following step 7-a to step 7-d:

• step 7-a:
• a clad composite material etching step wherein a clad composite material in which three layers of a first copper layer/a different kind of metal layer/a second copper layer are sequentially stacked has the different kind of metal layer constituted from a metal component which can be selectively etched against to copper, and using the clad composite material, only the second copper layer is etched with a copper selective etching solution to form a circuit pattern for etching on one surface, so that a clad composite material with circuit pattern is obtained;
• step 7-b:
• a laminating step wherein insulating layers are provided on both surfaces of the inner layer core material, and the etched circuit pattern surfaces of the clad composite material with circuit patterns obtained in the clad composite material etching step are placed onto and bonded to the base material surfaces on the both surfaces of the insulating layers, to form a multilayer metal-clad laminate in which the etched patterns are buried in the insulating layer;
• step 7-c:
• a first copper etching step wherein etching resist layers are formed on the first copper layers on the outer layer surfaces of the multilayer metal-clad laminate, and circuit pattern for etching is exposed and developed to etch the first copper layers located on the outer layers into desired circuit patterns with a copper selective etching solution, and then etching resist releasing is performed to remove unnecessary first copper layers;
• and
• step 7-d:
• a first different kind of metal etching step wherein after first copper etching step is finished, the different kind of metal layers exposed between circuits temporarily formed on the outer layers are etched away with a different kind of metal selective etching solution to simultaneously finish the first circuit 8 and the second circuit 9, so that the multilayer printed wiring board is obtained.