Wafer-level fabrication of optical devices with front focal length correction

A method for manufacturing a device, said method comprising:

• performing a correction step comprising manufacturing a spacer wafer, said spacer wafer including a multitude of regions defining a multitude of corresponding channels that are parallel to one another, each of the channels having a respective length defined by an extension of a respective one of the regions in a direction parallel to the channels;
• said spacer wafer comprising a first layer and a second layer which are made of different materials and which are vertically stacked one upon the other, each of said first layer and said second layer having a shape of a contiguous disk extending throughout each of said multitude of regions;
• wherein the manufacturing comprises, after an initial formation of the spacer wafer, decreasing a length of respective ones of said extensions in a plurality of said multitude of said regions so as to compensate at least partially for manufacturing variations in one or more other devices when the spacer wafer is combined with the one or more other devices, the spacer wafer being distinct from the one or more other devices, wherein said decreasing comprises performing, in each of said plurality of said multitude of said regions, a first processing step and subsequently performing a second processing step that differs from the first processing step in at least one aspect and
• wherein said decreasing the length is accomplished by removal of material from said second layer only.

A method for manufacturing a device, said method comprising:

• performing a correction step comprising manufacturing a spacer wafer, said spacer wafer including a multitude of regions defining a multitude of corresponding channels that are parallel to one another, each of the channels having a respective length defined by an extension of a respective one of the regions in a direction parallel to the channels;
• said spacer wafer comprising a first layer and a second layer which are made of different materials and which are vertically stacked one upon the other, each of said first layer and said second layer having a shape of a contiguous disk extending throughout each of said multitude of regions;
• wherein the manufacturing comprises, after an initial formation of the spacer wafer, decreasing a length of respective ones of said extensions in a plurality of said multitude of said regions so as to compensate at least partially for manufacturing variations in one or more other devices when the spacer wafer is combined with the one or more other devices, the spacer wafer being distinct from the one or more other devices, wherein said decreasing comprises performing, in each of said plurality of said multitude of said regions, a first processing step and subsequently performing a second processing step that differs from the first processing step in at least one aspect, and
• wherein said decreasing the length is accomplished by removal of material from said second layer only;
• the method further comprising attaching the spacer wafer to another wafer comprising the one or more other devices.