5G mmWAVE COOLING THROUGH PCB

Abstract

Embodiments of the invention include a mmWave transceiver and methods of forming such devices. In an embodiment, the mmWave transceiver includes an RF module. The RF module may include a package substrate, a plurality of antennas formed on the package substrate, and a die attached to a surface of the package substrate. In an embodiment, the mmWave transceiver may also include a mainboard mounted to the RF module with one or more solder balls. In an embodiment, a thermal feature is embedded within the mainboard, and the thermal feature is separated from the die by a thermal interface material (TIM) layer. According to an embodiment, the thermal features are slugs and/or vias. In an embodiment, the die compresses the TIM layer resulting in a TIM layer with minimal thickness.

What is claimed is: 
     
         1 . A method of forming a mmWave transceiver, comprising:
 fabricating a mainboard, wherein a plurality of thermal features are embedded within the mainboard;   forming a thermal interface material (TIM) layer over the plurality of thermal features;   positioning an RF module over the mainboard, wherein the RF module comprises:
 a plurality of antennas on a package substrate; 
 a plurality of dies on the surface of the package substrate, wherein each of the plurality of dies are aligned over one of the plurality of thermal features and in contact with the TIM layer; and 
 a plurality of solder balls; 
   reflowing the solder balls; and   applying pressure to the RF module during the reflowing of the solder balls.   
     
     
         2 . The method of  claim 1 , wherein the plurality of dies compress the TIM layer during the application of pressure to the RF module during the reflowing of the solder balls. 
     
     
         3 . The method of  claim 2 , wherein the compressed TIM layer has a thickness less than approximately 50 μm. 
     
     
         4 . The method of  claim 3 , wherein the compressed TIM layer has a thickness less than approximately 40 μm. 
     
     
         5 . The method of  claim 2 , wherein the compressed TIM layer has a thickness that is approximately equal to an average thickness of filler particles in the TIM layer. 
     
     
         6 . The method of  claim 1 , wherein the thermal features are slugs. 
     
     
         7 . The method of  claim 1 , wherein the thermal features are a plurality of vias. 
     
     
         8 . The method of  claim 1 , wherein the solder balls are ball grid array (BGA) balls. 
     
     
         9 . The method of  claim 8 , wherein the solder balls are between approximately 500 μm and 750 μm. 
     
     
         10 . The method of  claim 9 , wherein the solder balls are between approximately 630 μm and 700 μm. 
     
     
         11 . A method of fabricating a mmWave transceiver, the method comprising:
 forming an RF module, wherein the RF module comprises:
 a package substrate; 
 a plurality of antennas formed on the package substrate; 
 a first die attached to a surface of the package substrate; and 
 a second die attached to the surface of the package substrate; and 
   mounting a mainboard to the RF module with a plurality of solder balls, wherein a thermal feature is embedded within the mainboard, wherein the thermal feature is separated from the first die and the second die by a thermal interface material (TIM) layer, and wherein the first die and the second die are within a region inside of a footprint of the plurality of solder balls.   
     
     
         12 . The method of  claim 11 , wherein the thermal feature is a slug that passes completely through the mainboard. 
     
     
         13 . The method of  claim 11 , wherein the thermal feature is a plurality of vias that pass completely through the mainboard. 
     
     
         14 . The method of  claim 11 , further comprising:
 attaching a heat spreader to the mainboard, wherein the heat spreader is coupled to the thermal feature.   
     
     
         15 . The method of  claim 14 , wherein the heat spreader is coupled to the thermal feature by a second TIM layer. 
     
     
         16 . The method of  claim 14 , wherein the heat spreader is directly attached to the thermal feature. 
     
     
         17 . The method of  claim 11 , wherein the TIM layer is less than approximately 50 μm thick. 
     
     
         18 . The method of  claim 17 , wherein the TIM layer is less than approximately 40 μm thick. 
     
     
         19 . The method of  claim 11 , wherein the TIM layer has a thickness that is approximately equal to the average size of filler particles in the TIM layer. 
     
     
         20 . The method of  claim 11 , wherein the solder balls are ball grid array (BGA) balls.