A method for manufacturing vias in a glass substrate includes bonding, through a bonding layer, a first face of the glass substrate including a plurality of holes to a first face of a glass carrier. The bonding layer has a thickness t between the first face of the glass substrate and the first face of the glass carrier and extends into at least some of the plurality of holes to a depth h from the first face of the glass substrate. The method includes etching back the bonding layer to a depth d through the plurality of holes in the glass substrate. The depth d is less than the sum of the thickness t and the depth h. The method can include filling the plurality of holes with an electrically conductive material, and de-bonding the glass substrate from the bonding layer and the glass carrier.