| abstract |
A polyester film for dry films includes a polyester resin matrix and a plurality of spherical smoothing agents dispersed in the polyester resin matrix. The polyester resin matrix has a refractive index with a range from 1.5 to 1.7. Each of the spherical smoothing agents has a refractive index within a range from 1.3 to 1.9, a particle size within a range from 50 nm to 2 μm, and a circularity not less than 0.7. A surface of each of the spherical smoothing agents is covered with a siloxane compound or modified with siloxy to be in contact with the polyester resin matrix. The polyester film for dry films is a biaxially-stretched polyester film, and the polyester film for dry films has a haze not greater than 1%, a transparency not less than 85%, and a circuit resolution not greater than 10 μm. |