Plating apparatus and method
An apparatus forms a plated film in fine trenches and plugs for interconnects and in the openings of a resist formed in the surface of a substrate such as a semiconductor wafer, and forms bumps (protruding electrodes) on the surface of a semiconductor wafer. The apparatus includes a substrate holder capable of opening and closing for holding a substrate such that the front surface of the substrate is exposed while the backside and the edge thereof are hermetically sealed. A plating tank accommodates a plating liquid in which an anode is immersed. A diaphragm is provided in the plating tank and disposed between the anode and the substrate held by the substrate holder. Plating liquid circulating systems circulate the plating liquid to respective regions of the plating tank, separated by the diaphragm. A deaerating unit is disposed in at least one of the plating liquid circulating systems.
1. A plating method for plating a substrate, the plating method comprising:
providing a substrate holder having a first supporting member and a second supporting member for holding the substrate, a seal member, and a conductor for providing electricity to a surface to be plated of the substrate;
holding the substrate by clamping the substrate between the first and second supporting members such that a peripheral edge of the surface to be plated of the substrate, another surface of the substrate and the conductor are sealed from liquid with the seal member;
transferring the substrate held by the substrate holder to a pre-wetting tank;
immersing the substrate held by the substrate holder into a pre-wetting liquid so that a hydrophilic property of the surface to be plated of the substrate is improved;
transferring the pre-wetted substrate held by the substrate holder to a plating tank;
immersing the pre-wetted substrate held by the substrate holder into a plating liquid and connecting the conductor to an external electrode;
electroplating the pre-wetted substrate by supplying electricity between the surface to be plated of the substrate and an anode in the plating liquid;
transferring the substrate held by the substrate holder into a cleaning tank;
cleaning the substrate held by the substrate holder and the substrate holder together with a cleaning liquid in the cleaning tank;
removing the cleaning liquid from the surfaces of the substrate and the substrate holder by blowing air;
removing the substrate from the substrate holder by opening the first and second supporting members of the substrate holder; and
drying the substrate by spinning the substrate.
2. The plating method according to claim 1 , wherein
the conductor comprises a first conductor and a second conductor,
the first supporting member has the seal member and the first conductor, the first conductor for supplying electricity to the substrate, and
the second supporting member has the second conductor, the second conductor for supplying electricity from the external electrode to the first conductor.
3. The plating method according to claim 1 , wherein said electroplating of the pre-wetted substrate is performed while agitating the plating liquid.
4. The plating method according to claim 1 , further comprising:
transferring the pre-wetted substrate held by the substrate holder to a pre-soak tank prior to said electroplating of the pre-wetted substrate; and
immersing the pre-wetted substrate held by the substrate holder into a chemical liquid so that an oxidized layer on the surface to be plated of the substrate is removed by the chemical liquid.
5. The plating method according to claim 1 , wherein said immersing of the substrate held by the substrate holder into the pre-wetting liquid is performed while recovering the pre-wetted liquid that has overflowed the pre-wetting tank and supplying a dearated pre-wetting liquid to the pre-wetting tank.
6. The plating method according to claim 1 , further comprising:
reflowing the plated substrate after said drying to form a bump; and
annealing, after said reflowing, the substrate to remove residual stress in the bump formed on the substrate.