Patent ID: 7181963

Claim:
A thermal flow sensor comprising; a first substrate having a first side and a second opposite side; a second substrate having a first side and a second opposite side, said first substrate being connected to said second substrate such that said second side of said first substrate abuts said first side of said second substrate; a third substrate having a first side and a second opposite side, said third substrate being connected to said second substrate such that said second side of said second substrate abuts said first side of said third substrate; and wherein said first, second and third substrate forming a multi-layer body structure having at least one edge extending between a first side of said first substrate and said second side of said third substrate; said second substrate having a groove formed therein so as to form a conduit bounded by said second substrate and said second side of said first substrate and said first side of said third substrate, said conduit having an inlet opening and an outlet opening, each of said openings being formed in said at least one edge.