Method of manufacturing printed circuit board having landless via hole
Disclosed is a method of manufacturing a printed circuit board having a landless via hole. Specifically, this invention provides a method of manufacturing a printed circuit board having a landless via hole without the upper land of a via hole using a photoresist (P-LPR) which is loaded in the via hole. Therefore, in this invention, since a circuit pattern is formed using only copper of a copper clad laminate, the width thereof is minimized, thus easily realizing a fine circuit pattern. Further, the landless via hole structure is applied, resulting in a highly dense circuit pattern.
1. A method of manufacturing a printed circuit board having a landless via hole, comprising:
providing a base substrate composed of a copper clad laminate;
etching part of a copper foil of the copper clad laminate, to thus form a circuit pattern including a through hole;
sequentially forming a seed layer, a second metal layer having etching conditions different from those of copper, and a copper plating layer on an entire surface of the base substrate having the circuit pattern;
filling the through hole with a photoresist;
sequentially removing the copper plating layer, the second metal layer, and the seed layer; and
removing the photoresist from the through hole,
wherein the circuit pattern has a predetermined thickness corresponding to that of the copper foil.
2. The method as set forth in claim 1 , wherein the predetermined thickness of the circuit pattern is about 12˜18 μm.
3. The method as set forth in claim 2 , wherein the circuit pattern has a width of about 20 μm.
4. The method as set forth in claim 1 , wherein filling the through hole with the photoresist comprises:
applying the photoresist on the entire surface of the base substrate and in the through hole; and
exposing the photoresist to a depth corresponding to a thickness thereof, and performing development, to thus remove the photoresist from the surface of the base substrate.
5. The method as set forth in claim 4 , wherein the exposing of the photoresist is performed by controlling an exposure amount such that the photoresist is exposed to a depth corresponding to the thickness thereof.
6. The method as set forth in claim 1 , wherein the second metal layer is a nickel layer.
7. A method of manufacturing a printed circuit board having a landless via hole, comprising:
providing a base substrate including an inner layer circuit and composed of a copper clad laminate;
forming a circuit pattern, having a blind hole which is connected to the inner layer circuit, on a surface of the base substrate;
sequentially forming a seed layer, a second metal layer having etching conditions different from those of copper, and a copper plating layer on an entire surface of the base substrate having the circuit pattern;
filling the blind hole with a photoresist;
sequentially removing the copper plating layer, the second metal layer, and the seed layer; and
removing the photoresist from the blind hole,
wherein the circuit pattern has a predetermined thickness corresponding to that of a copper foil of the copper clad laminate.
8. The method as set forth in claim 7 , wherein the predetermined thickness of the circuit pattern is about 12˜18 μm.
9. The method as set forth in claim 8 , wherein the circuit pattern has a width of about 20 μm.
10. The method as set forth in claim 7 , wherein filling the blind hole with the photoresist (D) comprises:
applying the photoresist on the entire surface of the base substrate and in the blind hole; and
exposing the photoresist to a depth corresponding to a thickness thereof, and performing development, to thus remove the photoresist from the surface of the base substrate.
11. The method as set forth in claim 10 , wherein the exposing of the photoresist is performed by controlling an exposure amount such that the photoresist is exposed to a depth corresponding to the thickness thereof.
12. The method as set forth in claim 7 , wherein the second metal layer is a nickel layer.