Method of manufacturing optical sensor module and optical sensor module obtained thereby

A method of manufacturing an optical sensor module with a substrate unit in orthogonal relation to an optical waveguide unit, comprising the steps of:

• preparing an optical waveguide unit including an under cladding layer, and protruding portions having vertical walls for the positioning of a substrate unit, the protruding portions being formed on a surface portion of the under cladding layer lying in an appropriate position for the transmission and reception of light relative to a light-transmitting and light-receiving end portion of a core;
• preparing a substrate unit including an optical element mounted therein, and positioning plate portions formed by etching, the positioning plate portions having respective lower end edges and respective corners, the positioning plate portions being positioned by the placement of the lower end edges thereof on the surface of the under cladding layer and by the abutment of the corners thereof against the vertical walls of the protruding portions so that the optical element is in an appropriate position relative to the light-transmitting and light-receiving end portion of the core;
• and
• placing the substrate unit in orthogonal relation to the optical waveguide unit, and positioning the positioning plate portions of the substrate unit relative to the under cladding layer and the protruding portions of the optical waveguide unit, thereby positioning and fixing the substrate unit to the optical waveguide unit,
• wherein, in the optical waveguide unit, the vertical walls of the protruding portions for the positioning of the substrate unit have a height less than 50 μm, and
• wherein, in the substrate unit, each of the corners of the positioning plate portions has at least a portion formed as a positioning member made of the same material as an interconnecting metal layer of the substrate unit, whereby the corners become substantially right-angled corners.