the present invention is a backside illumination system for illuminating the backside of semiconductor or microelectronic wafers or substrates where the wafers or substrates are transparent , translucent , opaque or otherwise capable of transmitting at least some of the illumination through the wafer or substrate to illuminating features therein , thereon the backside , or associated therewith . this invention is designed to be useful with any inspection process , including for example the automated defect inspection system described in commonly owned u . s . provisional application nos . 60 / 092 , 923 and 60 / 092 , 701 , filed on jul . 15 , 1998 , and u . s . patent application ser . no . 09 / 352 , 564 , filed on jul . 13 , 1999 , all of which are hereby incorporated by reference such that the backside illumination allows for inspection and viewing of the features on the backside or within the wafer from the front side . the backside illumination system is indicated generally as s as is shown in the figures . the system includes a heat sink 1 , a light assembly 2 , a clamp ring 3 , a radiator 4 , a diffuser ring 5 , a diffuser glass 6 , a top ring 7 , a top or opal glass 8 , a plurality of fasteners 9 - 12 , a stop pin 13 , a wire cover 14 , a connector board assembly 15 , a rotatable air fitting 16 , a base 17 , a hardstop 18 , a sensor mount bracket 19 , a hardstop back 20 , and a power wire assembly 21 . heat sink 1 is preferably an aluminum heat sink for dissipating heat from the backside illumination system and specifically the light assembly . the heat sink 1 in the preferred embodiment includes a center hole for receiving the light assembly where the light assembly seats on a ledge therein . light assembly 2 is any form of light for illumination . in the preferred embodiment , the light assembly 2 is a led assembly including a plurality of leds or light emitting diodes . in this preferred design , the leds are arranged in a circular array format as is shown in the figures whereby the leds are arranged to maximize the number provided . clamp ring 3 is a ring for securing or clamping the light assembly 2 to the heat sink 1 . the light assembly is seated on the ledge in the heat sink and then the clamp ring secures it in place . radiator 4 is designed to radiate heat away from the light assembly . the light assembly when embodied as an led assembly with tens , hundreds , or even thousands of leds creates significant heat . the heat sink functions to dissipate the heat away from the led assembly . the radiator in turn functions to radiate this heat to the atmosphere . as a result , the radiator needs to be of a radial fin design as is shown in the figures so as to provide maximum surface area to best radiate off the significant heat created by the led assembly . diffuser glass 6 and the diffuser ring 5 that secures the glass in the radiator 4 are provided to diffuse the led light radiating from the leds into a more even or diffuse pattern . top glass 8 and the top ring 7 that secures the glass in the radiator are provided as a top surface . it is on this surface that the wafers are inspected . the system s provides illumination on the back side of a wafer or substrate while sitting on an inspection plate or stage . other illumination such as brightfield or darkfield may also be provided . this backside illumination provides high intensity visible light that illuminates through either ( 1 ) a silicon wafer or substrate with light passages therein , or ( 2 ) a non - silicon wafer or substrate made of glass or a type iii - v or ii - vi compound such as gallium arsenide , indium phosphide , silicon carbide , or oxide based materials which includes quartz and fused silica compounds . this allows for viewing from the top or front side of features on the backside or within the wafer or substrate . accordingly , the invention as described above and understood by one of skill in the art is simplified , provides an effective , safe , inexpensive , and efficient device , system and process which achieves all the enumerated objectives , provides for eliminating difficulties encountered with prior devices , systems and processes , and solves problems and obtains new results in the art . in the foregoing description , certain terms have been used for brevity , clearness and understanding ; but no unnecessary limitations are to be implied therefrom beyond the requirement of the prior art , because such terms are used for descriptive purposes and are intended to be broadly construed . moreover , the invention &# 39 ; s description and illustration is by way of example , and the invention &# 39 ; s scope is not limited to the exact details shown or described . having now described the features , discoveries and principles of the invention , the manner in which it is constructed and used , the characteristics of the construction , and the advantageous , new and useful results obtained ; the new and useful structures , devices , elements , arrangements , parts and combinations , are set forth in the appended claims .