A method of manufacturing a glass substrate to control the fragmentation characteristics by etching and filling trenches in the glass substrate is disclosed. An etching pattern may be determined. The etching pattern may outline where trenches will be etched into a surface of the glass substrate. The etching pattern may be configured so that the glass substrate, when fractured, has a smaller fragmentation size than chemically strengthened glass that has not been etched. A mask may be created in accordance with the etching pattern, and the mask may be applied to a surface of the glass substrate. The surface of the glass substrate may then be etched to create trenches. A filler material may be deposited into the trenches.