Optoelectronic modules having a silicon substrate, and fabrication methods for such modules
Optoelectronic modules include a silicon substrate in which or on which there is an optoelectronic device. An optics assembly is disposed over the optoelectronic device, and a spacer separates the silicon substrate from the optics assembly. Methods of fabricating such modules also are described.
1. A method comprising:
placing a first wafer comprising optoelectronic components on a first vacuum injection tool;
applying a second vacuum injection tool over the first wafer such that the first and second vacuum injection tools define spaces separating channels from one another, wherein each of the channels is associated with a respective one of the optoelectronic components;
injecting an epoxy into the spaces to form a spacer that extends beyond a surface of the first wafer, the spacer having a free end;
subsequently machining portions of the free end of the spacer so that different regions of the spacer extend different amounts beyond the surface of the first wafer;
subsequently placing optics assemblies on the free end of the spacer so as to obtain a resulting structure in which each of the optics assemblies is disposed over a different respective one of the optoelectronic components, wherein at least some of the optics assemblies are disposed at a distance from the first wafer that differs from a distance at which other ones of the optics assemblies are disposed; and
separating the resulting structure into a plurality of optoelectronic modules each of which includes at least one of the optoelectronic components and at least one of the optics assemblies.
2. The method of claim 1 further including:
performing optical measurements of the optoelectronic components;
wherein machining portions of the free end of the spacer changes how far different regions of the spacer extend beyond the surface of the first wafer, an amount of the machining at each respective portion being based, at least in part, on results of the optical measurements.
3. The method of claim 2 wherein the amount of machining of the spacer at each respective region is based on a target focal length.
4. The method of claim 1 wherein separating the resulting structure into a plurality of optoelectronic modules includes dicing along lines passing through the spacer in a direction perpendicular to the first wafer.
5. The method of claim 1 wherein injecting an epoxy into the spaces to form a spacer includes injecting an epoxy with a non-transparent filler.
6. The method of claim 1 wherein the portions of the free end of the spacer are machined to correct a focal length of one or more of the channels.
7. The method of claim 1 including placing the optics assemblies on the free end of the spacer by pick-and-place equipment.
8. The method of claim 1 including separating the resulting structure into a plurality of optoelectronic modules each of which includes a plurality of optoelectronic components and a corresponding optics assembly disposed over each respective one of the optoelectronic components, and wherein the optics assemblies are disposed at different distances above the respective optoelectronic components.
9. The method of claim 1 further including providing a focal length correction layer to adjust a focal length of one or more of the channels.