Methods to fabricate a photoactive substrate suitable for microfabrication

A method to fabricate a device with microfluidics for in-package cooling comprising the steps of:

• preparing a photosensitive glass substrate comprising at least silica, lithium oxide, aluminum oxide, and cerium oxide;
• masking a design layout comprising an inlet and an outlet connected by one or more microfluidic channels for transport of a fluid on the photosensitive glass substrate and one or more holes in the photosensitive glass substrate;
• exposing at least one portion of the photosensitive glass substrate to an activating energy source;
• exposing the photosensitive glass substrate to a heating phase of at least ten minutes at a temperature above its glass transition temperature of the photosensitive glass-ceramic substrate:
• cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline ceramic substrate;
• exposing an outer surface to an etchant solution;
• and
• etching the glass-crystalline ceramic substrate with the etchant solution to form an etched design layout accessible from the outer surface with the inlet and the outlet connected by the one or more microfluidic channels to transport the fluid on the glass-crystalline ceramic substrate and to form one or more holes through the glass-crystalline ceramic substrate for transport of a fluid in the device, wherein the one or more holes are formed through the photosensitive glass substrate and the one or more microfluidic channels are formed on the surface of the photosensitive glass substrate.

A method to fabricate a substrate with one or more optical wave guides comprising the steps of:

• preparing a photosensitive glass substrate comprising at least silica, lithium oxide, aluminum oxide, and cerium oxide;
• forming one or more metal vias in the photosensitive glass substrate;
• masking a design layout comprising an inlet and an outlet connected by one or more paths oriented within the photosensitive glass substrate in optical communication with the one or more metal vias;
• exposing at least one portion of the photosensitive glass substrate to an activating energy source;
• exposing the photosensitive glass substrate to a heating phase of at least ten minutes at a temperature above its glass transition temperature of the photosensitive glass-ceramic substrate;
• cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline substrate;
• exposing an outer surface to an etchant solution;
• and
• etching the glass-crystalline substrate with an etchant solution to form an etched design layout to form one or more paths accessible from the outer surface;
• filling the one or more metal vias with a composition comprising a metal;
• wherein the one or more paths are in optical communication with the one or more metal vias to transport and reflect the light in the substrate.

A method to fabricate a substrate with one or more optical wave guides comprising the steps of:

• preparing a photosensitive glass substrate comprising at least silica, lithium oxide, aluminum oxide, and cerium oxide;
• forming one or more metal vias in the photosensitive glass substrate;
• masking a design layout comprising an inlet and an outlet connected by one or more paths oriented within the photosensitive glass substrate in optical communication with the one or more metal vias;
• exposing at least one portion of the photosensitive glass substrate to an activating energy source;
• exposing the photosensitive glass substrate to a heating phase of at least ten minutes at a temperature above its glass transition temperature of the photosensitive glass-ceramic substrate;
• cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline substrate;
• etching the glass-crystalline substrate with an etchant solution to form an etched design layout wherein the one or more paths are in optical communication with the one or more metal vias to transport and reflect the light in the substrate;
• and
• coating the one or more paths with a second dielectric coating material.