a semiconductor integrated circuit device , such as an integrated circuit ( ic ) or multichip module ( mcm ) 10 to be coated in accordance with the present invention is illustrated generally in fig1 . the ic or mcm 10 includes a single , active circuitry semiconductor chip 12 ( in the case of an ic ) or multiple , active circuitry semiconductor chips 12 ( in the case of a mcm ). the semiconductor chip ( s ) 12 is mounted on a surface 13 of a substrate 14 and includes lead wires 16 that are connected to pads 18 also mounted on the surface 13 of the substrate 14 . the pads 18 serve as ports for electrical connection to external sources ( not shown ). the substrate 14 with the chip ( s ) 12 and pads 18 mounted thereto is housed within a ceramic package 20 defined by a base member 22 , a lid member 24 and a lid seal 26 ( the lid member 24 and lid seal 26 not being shown in fig1 .). the ic or mcm 10 is coated with a protective opaque coating 28 ( see fig3 ) by a thermal spray process 29 illustrated in fig2 . the thermal spray process 29 , of the present invention , is a line of sight coating process that includes a thermal spray gun 30 having a nozzle 31 . a heat energy source 32 is delivered to the nozzle 31 ( in a known manner ) to heat a ceramic particle based coating composition 33 also delivered to the nozzle 31 ( in a known manner ). the heat energy source 32 uses a flame 34 to heat the coating composition 33 to a molten state defined by molten liquefied particles 35 . the molten liquefied particles 35 defining the coating composition 33 are carried to the ic or mcm 10 by a carrier gas jet 36 also delivered to the nozzle 31 ( in a known manner ). the ic or mcm 10 is supported on a support element 38 that may act as heat sink during the coating process . the thermal spray process 29 first requires the preparation of the ceramic particle based coating composition 33 . it is desirable that the chemistry of the coating composition 33 be similar to the chemistry of the materials of the ic or mcm 10 , such that attempted removal of the protective opaque coating 28 ( formed from the coating composition 33 ) from the ic or mcm 10 ( for inspection and / or reverse engineering of the topology of the ic or mcm ) via chemical methods will simultaneously destroy the ic or mcm 10 . in the present invention , the coating composition 33 may be a single chemical component or a multi chemical component composition , partially or entirely formed from any one of alumnina , beryllia , silica , silicon carbide , aluminum nitride , fused alumina - titanium oxide , fused alumina - titanium dioxide and nylon or alumina - titanium oxide , barium titanate , or other ceramic oxides or silicates and teflon . in one preferred embodiment fused alumina - titanium oxide was found to provide a desirable coating composition 33 for the protective opaque coating 28 . the coating composition 33 is prepared by manufacturing the chemical materials of the coating composition 33 into a powder or sintered rod having particle sizes within the range of ten microns to sixty microns . particle sizes in excess of sixty microns tend to cause mechanical damage to the ic or mcm 10 due to that force at which the carrier gas jet 36 delivers the molten liquefied particles 35 to the ic or mcm 10 . particle sizes less than ten microns tend to cause transformation of the particle based coating composition 33 into a liquid stream ( rather than molten liquefied particles 35 ) that may be difficult to control during the application process . in one preferred embodiment , a coating composition 33 prepared in the form of a sintered rod with the coating composition 33 having a particle size within the range of ten microns to twenty microns is desirable . once the coating composition 33 is prepared , the coating composition 33 , the heat energy source 32 and the carrier gas jet 36 are simultaneously delivered to the nozzle 31 of the thermal spray gun 30 . the heat energy source 32 can take the form of a plasma arc , an electric arc or a fuel gas . in one preferred embodiment , the heat energy source is a fuel gas 40 ( preferably acetylene ) which is combined with oxygen 42 to create that flame 34 that is of a temperature sufficient to transform the ceramic particle based coating composition 33 to molten liquefied particles 35 . in one preferred embodiment , this temperature is in the range of between 200 ° c . and 2500 ° c . the molten liquefied particles 35 are applied to the ic or mcm 10 via the carrier gas jet 36 which carries the molten liquefied particles 35 to the ic or mcm 10 and causes the particles 35 to impact upon the ic or mcm 10 . the molten liquefied particles 35 undergo a “ splat ” upon impact with the surface of the ic or mcm 10 , and then coalesce to form a contiguous coating that thickens with continued successive depositions of the molten liquefied particles 35 to form the lamellar protective opaque coating 28 . in one preferred embodiment , the carrier gas jet 36 is pressurized nitrogen which is delivered to the nozzle 31 of the thermal spray gun 30 in the range of 10 - 100 cfm . as seen in fig2 in practice , the nozzle 31 of the thermal spray gun 30 is positioned above the ic or mcm 10 which is held in place by the support element 38 which can draw heat away from the ic or mcm 10 during the application process . typically , the nozzle 31 is positioned from the ic or mcm 10 within the range of between five inches and seven inches . in one preferred embodiment , the nozzle 31 is positioned six inches from the ic or mcm 10 . the molten liquefied particles 35 can be applied in successive layers or as a single burst depending upon the desired coating thickness and the thermal limitations of the ic or mcm 10 . in one preferred embodiment , the thickness of the formed protective coating 28 is in the range of between 1 mils and 100 mils . the molten liquefied particles 35 are applied by moving the nozzle 31 of the thermal spray gun 30 back and forth over the surface of the ic or mcm 10 , or by moving the ic or mcm 10 relative to the nozzle 31 , or by moving both the nozzle 31 and the ic or mcm 10 relative to one another . in one preferred embodiment , the nozzle 31 is moved relative to a moving ic or mcm 10 . once the molten liquefied particles 35 are applied , they form a lamellar protective opaque coating that adhesively bonds to the surface of the ic or mcm 10 and is abrasion resistant , provides a hermetic seal , and prevents both active and passive , chemical , optical and radiation based inspection and / or reverse engineering of the active and inactive circuitry of the ic or mcm 10 . as seen in fig3 the formed protective opaque coating 28 completely covers the semiconductor chip ( s ) 12 , lead wires 16 , pads 18 and the surface 13 of the substrate 14 housed within the base member 22 . however , the protective , opaque coating 28 may be applied so as to only partially or completely cover any one of or more of the semiconductor chip ( s ) 12 , leads 16 , pads 18 and / or surface 13 . once the protective opaque coating 28 is formed , the lid seal 26 and the lid member 24 are mounted on the base member 22 to further hermetically seal the ic or mcm 10 . the molten liquefied particles 35 can be applied to the surface of the ic or mcm 10 ( to achieve complete coverage as shown in fig3 ) in 15 to 600 seconds . the protective opaque coating 28 can be fully applied and cooled and the ic or mcm 10 ready for use in only 1 to 70 minutes . therefore , the thermal spray process is capable of producing inspection and / or reverse engineering proof ic &# 39 ; s or mcm &# 39 ; s 10 in a time efficient and cost effective manner that permits coating application on a mass production level . although the present invention has been described with reference to preferred embodiments , workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention .