Systems and methods for providing electromagnetic interference shielding for integrated circuit modules

Abstract

An automated system for maintaining paint thickness uniformity over the surface of a cap encapsulating at least one integrated circuit (IC) module on a panel of IC modules is provided. The system can be computer implemented and applies a layer of conductive paint that electrically couples with wirebonds on the panel to form at least part of an electromagnetic interference (EMI) or radio frequency interference (RFI) shield that attenuates EMI or RFI during operation of the IC module. The system optimizes the spray nozzle diameter, fluid pressure, coaxial air pressure, spray heights, speeds, and spray pattern achieves paint thickness control. A uniform coating of conductive paint provides a more effective EMI or RFI shield during the operation of the IC modules.

1 . (canceled) 
     
     
         2 . A system for spraying a surface of a panel of integrated circuit modules with conductive paint, the system comprising:
 a spray apparatus;   computer hardware including at least one computer processor; and   computer-readable storage having computer-readable instructions that, when executed by the computer processor, cause the computer hardware to control the spray apparatus to perform operations including (i) spraying N axially elongate first bands of conductive paint including metal particles along a longitudinal axis of a panel including integrated circuit modules and advancing along a vertical axis of the panel a first distance after spraying each first band of the conductive paint, and (ii) spraying N+1 axially elongate second bands of the conductive paint along the longitudinal axis of the panel and advancing along the vertical axis of the panel a second distance after spraying each second band of the conductive paint, the second bands of the conductive paint being interspersed between the first bands of the conductive paint to provide an approximately uniform layer of the conductive paint over an upper surface of the panel, the layer of conductive paint electrically coupling with wirebonds on the panel to form at least part of an electromagnetic interference or radio frequency interference shield.   
     
     
         3 . The system of  claim 2  wherein a thickness of the layer of the conductive paint is approximately 25 microns±approximately 5 microns. 
     
     
         4 . The system of  claim 3  wherein flatness of the layer of conductive paint is approximately 1% of the thickness of the conductive paint. 
     
     
         5 . The system of  claim 2  wherein the operations further include spraying a layer of conductive paint over the perimeter of the panel prior to spraying the N axially elongate first bands. 
     
     
         6 . The system of  claim 2  wherein the electromagnetic interference or radio frequency interference shield includes the layer of the conductive paint in electrical contact with a plurality of wirebonds encircling the integrated circuit module. 
     
     
         7 . The system of  claim 2  wherein the operations further include adjusting at least one parameter of the spray apparatus chosen from the group consisting of a valve pressure, a needle size, an air cap, a fluid pressure, an air assist pressure, a fluid on time, a fluid off time, an air assist on time, an air assist off time, a height of a nozzle above the upper surface, a travel speed of the nozzle, and an initial position of the nozzle. 
     
     
         8 . The system of  claim 7  wherein controlling at least one parameter on the spray apparatus is based on one or both of a metal particle size and a viscosity of the conductive paint. 
     
     
         9 . The system of  claim 2  wherein the metal particles include metal flakes having an irregular shape and the approximately uniform layer of the conductive paint over the upper surface of the panel includes approximately covering the upper surface with the metal flakes. 
     
     
         10 . The system of  claim 2  wherein N+1 axially elongate second bands is determined by rounding up a height of the panel minus twice a width of a perimeter band of the conductive paint divided by a width of the second band of the conductive paint to an integer value. 
     
     
         11 . The system of  claim 2 , wherein the computer-readable instructions are programmed by a user. 
     
     
         12 . A system for spraying a surface of a panel of integrated circuit modules with conductive paint, the system comprising:
 a spray apparatus;   computer hardware including at least one computer processor; and   computer-readable storage having computer-readable instructions that, when executed by the computer processor, cause the computer hardware to control the spray apparatus to perform operations including (i) spraying N axially elongate first bands of conductive paint including metal particles along a longitudinal axis of a panel including integrated circuit modules and advancing along a vertical axis of the panel a first distance after spraying each first band of the conductive paint, (ii) spraying a perimeter layer of conductive paint over a perimeter of the panel of integrated circuit modules after spraying the N axially elongate first bands, the N axially elongate first bands being in electrical contact with the perimeter layer of conductive paint over the perimeter of the panel, and (iii) spraying N+1 axially elongate second bands of the conductive paint along the longitudinal axis of the panel and advancing along the vertical axis of the panel a second distance after each second band of the conductive paint, the second bands of the conductive paint being interspersed between the first bands of the conductive paint to provide an approximately uniform first layer of the conductive paint over an upper surface of the panel, the layer of conductive paint electrically coupling with wirebonds on the panel to form at least part of an electromagnetic interference or radio frequency interference shield.   
     
     
         13 . The system of  claim 12  wherein a thickness of the layer of the conductive paint is approximately 25 microns±approximately 5 microns. 
     
     
         14 . The system of  claim 13  wherein flatness of the layer of conductive paint is approximately 1% of the thickness of the conductive paint. 
     
     
         15 . The system of  claim 14  wherein the computer readable instructions include spraying a first perimeter layer of conductive paint over the perimeter of the panel prior to spraying the N axially elongate first bands. 
     
     
         16 . The system of  claim 15  wherein the computer readable instructions include determining whether a desired paint thickness has been obtained, and if the desired thickness has not been reached then repeating the spraying of the first perimeter layer, the N axially elongate first bands, the perimeter layer, and the N+1 axially elongate second bands to provide an approximately uniform second layer of conductive paint over the approximately uniform first layer of conductive paint. 
     
     
         17 . The system of  claim 12  wherein the electromagnetic interference or radio frequency interference shield includes the layer of the conductive paint in electrical contact with a plurality of wirebonds encircling the integrated circuit module. 
     
     
         18 . The system of  claim 12  wherein the computer-readable instructions further include controlling on the spray apparatus at least one parameter chosen from a group consisting of a valve pressure, a needle size, an air cap, a fluid pressure, an air assist pressure, a fluid on time, a fluid off time, an air assist on time, an air assist off time, a height of a nozzle above the upper surface, a travel speed of the nozzle, and an initial position of the nozzle. 
     
     
         19 . The system of  claim 18  wherein the controlling of the at least one parameter is based on one or both of a metal particle size and a viscosity of the conductive paint 
     
     
         20 . The system of  claim 12 , wherein the computer-readable instructions are programmed by a user.