Patent ID: 7495167

Claim:
A production method of silicon solar cell having an n + pp + structure with a phosphorus-diffused n + layer formed on a first side of p-type silicon substrate and boron-diffused p + layer formed on a second side of said p-type silicon substrate, comprising the steps of: a back side boron diffusion step for diffusing-treating boron on a back side of the silicon substrate, a front side phosphorus diffusion step for diffusing phosphorus on a front side of the silicon substrate after the back side boron diffusion step, a low-temperature annealing step for annealing the substrate at 600° C. or lower for 1 hour or more after the front side phosphorus diffusion step, providing grid-shape electrodes on both the first side and the second side of the p-type substrate, and providing each of the grid-shape electrodes with a finger electrode and a busbar electrode, wherein the width of the finger electrode is narrower than 100 μm, the width of the busbar electrode is wider than 10 times of the width of the finger electrode, and the width of the finger electrode is made wider at a base portion at which the finger electrode and the busbar electrode are connected to each other.