Method of forming an assembly to house one or more micro components

#This disclosure relates to techniques for providing a structure with through-holes that may be used, for example, in a sub-assembly for micro components.

#Sub-assemblies for micro components such as optoelectronic devices or optoelectronic hybrid integrated circuits may include a semiconductor structure formed as a lid, which may be sealed to a base. One or more active and passive micro components may be encapsulated within the sub-assembly. Typically, electrical or optical connections may need to be provided to the components mounted within the assembly.

#The assignee of the present application previously has disclosed, in U.S. Published application Ser. No. 2003/0071283, a double-sided etching technique for providing a semiconductor structure with one or more through-holes, which may be sealed hermetically, for example, by a feed-through metallization process. The structure in which the through-holes are formed may include a silicon-on-insulator (SOI) structure. Electrical contacts to an optoelectronic or other component housed within the assembly may be provided via the feed-through metallization.

#FIG. 1. is a cross-section of an example of an assembly that houses a MEMS device according to the invention.

#FIGS. 2 and 3 illustrate formation of a lid for the assembly using pre-processed sub-structures.

#FIGS. 4 through 7 illustrate various shapes of through-holes in the lower sub-structure for the lid.

#As shown in FIG. 1, an assembly 20 for a MEMS component 24 includes two structures 22, 25 that are soldered together to provide a hermetically sealed package that encapsulates the MEMS device. The bottom structure 22 includes a semiconductor or other substrate that serves as a base on which the MEMS device 24 is mounted or in which the MEMS device is formed. Metal leads 28 may be provided on the surface of the base and are electrically connected to the MEMS device 24. The upper structure 25 serves as a lid and includes feed-through metallization 27 to permit electrical connections from the exterior of the package to the MEMS device inside the package. A recessed cavity 40 is provided in the lower section of the lid 25 to allow room for the MEMS device.

#The feed-through metallization 27 extends through one or more micro-vias (i.e., through-holes) in the upper section of the lid 25. The feed-through metallization 27 extends along the outer surface of the lid 25 and is electrically connected to solder bumps 32 for printed board assembly. The feed-through metallization 27 also extends outside the recessed cavity 40 along the cavity-side surface of the lid structure 25. Solder 30 is deposited onto the feed-through metallization outside the recessed cavity 40 to provide solder bumps for electrical connection to the metal leads 28. Additional solder 30 is deposited on the cavity-side of the lid structure 25 to provide a solder seal ring.

#Other active and passive micro components may be mounted to the base 22 and encapsulated within the package. Although in FIG. 1 the feed-through metallization 27 is shown extending through only two through-holes in the upper section of the lid 25, feed-through metallization may be provided through additional through-holes for electrical contact to the same or other micro components in the package.