A method of bonding at least a first substrate to a second substrate, the method comprising: providing a first substrate, the first substrate having a front main surface and at least one protrusion at the front main surface, the protrusion comprising at least a metal portion, the protrusion having side walls which are perpendicular to the front main surface of the first substrate, providing a second substrate, the second substrate having a front main surface and at least one hole extending into the second substrate, the at least one hole comprising a metal layer on at least part of the sidewalls of the hole, the at least one hole being shaped such that at least one of its dimensions in a cross-section parallel with the front main surface of the second substrate is continuously reduced in a depth direction, the hole and the protrusion being shaped so that at least one bottom dimension (Ø b) of the hole in a cross-section parallel to the front main surface of the second substrate is smaller than the corresponding dimension (Ø t) of the corresponding protrusion in a cross-section parallel to the front main surface of the first substrate, and at least one dimension (Ø bt) at the top of the hole in a cross-section parallel to the front main surface of the second substrate is larger than the corresponding dimensions (Ø t) of the corresponding protrusion in a cross-section parallel to the front main surface of the first substrate, aligning the at least one protrusion of the first substrate with a corresponding at least one hole of the second substrate, and clamping the first and second substrate (30, 32) by inserting the at least one protrusion of the first substrate into the at least one hole of the second substrate, the protrusion being arranged and constructed to be plastically deformed during insertion thereof in the hole so as to provide a bond between the metal layer at the sidewalls of the hole and the metal portion of the protrusion, and pushing the protrusion deeper into the hole in the second substrate. providing a first substrate, the first substrate having a front main surface and at least one protrusion at the front main surface, the protrusion comprising at least a metal portion, the protrusion having side walls which are perpendicular to the front main surface of the first substrate, providing a second substrate, the second substrate having a front main surface and at least one hole extending into the second substrate, the at least one hole comprising a metal layer on at least part of the sidewalls of the hole, the at least one hole being shaped such that at least one of its dimensions in a cross-section parallel with the front main surface of the second substrate is continuously reduced in a depth direction, the hole and the protrusion being shaped so that at least one bottom dimension (Ø b) of the hole in a cross-section parallel to the front main surface of the second substrate is smaller than the corresponding dimension (Ø t) of the corresponding protrusion in a cross-section parallel to the front main surface of the first substrate, and at least one dimension (Ø bt) at the top of the hole in a cross-section parallel to the front main surface of the second substrate is larger than the corresponding dimensions (Ø t) of the corresponding protrusion in a cross-section parallel to the front main surface of the first substrate, aligning the at least one protrusion of the first substrate with a corresponding at least one hole of the second substrate, and clamping the first and second substrate (30, 32) by inserting the at least one protrusion of the first substrate into the at least one hole of the second substrate, the protrusion being arranged and constructed to be plastically deformed during insertion thereof in the hole so as to provide a bond between the metal layer at the sidewalls of the hole and the metal portion of the protrusion, and pushing the protrusion deeper into the hole in the second substrate.