Method of bonding substrates, microchip and method of manufacturing the same

A microchip having a flow channel in which a medium flows, the microchip comprising:

• a first substrate and a second substrate bonded directly to each other without any adhesive agent intervening or a solvent bonded interface between the substrates, each of the first substrate and the second substrate being made of glass or a resin;
• a plurality of joining regions provided on at least one of a joining surface of the first substrate and a joining surface of the second substrate;
• a plurality of flow channel forming portions each arranged within at least one of the plurality of joining regions and configured to form a flow channel in which a medium flows during use;
• and
• a segmenting recessed portion arranged to extend at least longitudinally or transversely to an edge of the first substrate or the second substrate to segment the joining surface of the first substrate or the second substrate into the plurality of joining regions to be separate from one another,
• wherein the segmenting recessed portion is not in fluid contact with the plurality of flow channel forming portions.