Etch back processes of bonding material for the manufacture of through-glass vias

A method for manufacturing a plurality of vias in a substrate, the method comprising:

• bonding a first face of the substrate including a plurality of holes to a first face of a carrier with a bonding layer, wherein the bonding layer has a thickness t between the first face of the substrate and the first face of the carrier;
• etching, using a wet etch process, the bonding layer to a depth d through the plurality of holes in the substrate;
• filling the plurality of holes with an electrically conductive material to form the plurality of vias in the glass, wherein the electrically conductive material extends into the bonding layer by a length l, and wherein the length l is less than the thickness t;
• and
• de-bonding the substrate including the plurality of vias from the bonding layer and the carrier, wherein the electrically conductive material protrudes from the first face of the substrate.

A method for manufacturing a plurality of vias in a substrate, the method comprising:

• bonding a first face of the substrate including a plurality of holes to a first face of a carrier using a bonding layer, wherein the bonding layer has a thickness t between the first face of the substrate and the first face of the carrier;
• etching, using a dry etch process, the bonding layer to a depth d through the plurality of holes in the substrate, wherein the depth d is equal to the sum of a length l into which the etching extended into the bonding layer from the first face of the substrate and a height h of an adhesive plug formed by the bonding layer extending into at least some of the plurality of holes, wherein the length l is equal to the thickness t, the first face of the carrier being a stop layer for the dry etch process;
• filling the plurality of holes with an electrically conductive material to form the plurality of vias in the substrate, wherein the electrically conductive material extends through the bonding layer to the first face of the carrier;
• and
• de-bonding the substrate including the plurality of vias from the bonding layer and the carrier, wherein the electrically conductive material forms pillars extending from the first face of the glass substrate the length l.