Micro heat pipe for use in semiconductor IC chip package

A chip package comprising:

• a circuit substrate;
• a plurality of first solder balls at a bottom of the chip package and under the circuit substrate;
• a sub-system package over the circuit substrate, wherein the sub-system package comprises:
• a first interconnection scheme comprising a first interconnection metal layer, a second interconnection metal layer over the first interconnection metal layer and an insulating dielectric layer between the first and second interconnection metal layers,
• a first metal bump at a bottom of the sub-system package, under and coupling to the first interconnection scheme and bonded to the circuit substrate,
• a first integrated-circuit (IC) chip over and coupling to the first interconnection scheme, and
• a second integrated-circuit (IC) chip over and coupling to the first integrated-circuit (IC) chip;
• and
• an optical module over the circuit substrate, wherein the optical module comprises:
• a second interconnection scheme,
• a plurality of second solder balls at a bottom of the optical module, under the second interconnection scheme and coupling to the circuit substrate, and
• an optical chip over and coupling to the second interconnection scheme, wherein the optical chip comprises a silicon layer and an optical waveguide having a portion in the silicon layer and the optical chip further comprises an insulating layer on a top surface of the silicon layer and over the optical waveguide, wherein the optical waveguide is configured to be coupled to an optical fiber by a first optical signal, wherein the optical fiber is configured to transmit the first optical signal from above the insulating layer to the optical waveguide under the insulating layer.