Packaging structure and method of a photosensitive module

Abstract

A semiconductor die includes a semiconductor device fabricated in a substrate. The substrate has a front side, a back side, and an inclined sidewall extending from the back side to the front side. A contact pad is connected to the semiconductor device. The contact pad is embedded in an inter dielectric layer (IDL) disposed in the front side. The contact pad has a contact pad edge with a surface aligned along the inclined sidewall. A redistribution layer (RDL) is disposed on the inclined sidewall. The RDL is physically and electrically connected to the contact pad directly through the surface of the contact pad edge aligned along the inclined sidewall.

1 . A semiconductor die, comprising:
 a substrate including a semiconductor device, the substrate having a front side, a back side, and an inclined sidewall extending from the back side to the front side;   a contact pad connected to the semiconductor device, the contact pad embedded in an inter dielectric layer (IDL) disposed in the front side and the contact pad having a contact pad edge with a surface aligned along the inclined sidewall; and   a redistribution layer (RDL) disposed on the inclined sidewall, the RDL being physically and electrically connected to the contact pad directly through the surface of the contact pad edge aligned along the inclined sidewall.   
     
     
         2 . The semiconductor die of  claim 1 , wherein the inclined sidewall includes a first inclined section extending from the back side toward the front side along a semiconductor material of the semiconductor die, a flat step section disposed above the contact pad embedded in the IDL disposed on the front side, and a second inclined section extending along an edge of the IDL disposed the front side. 
     
     
         3 . The semiconductor die of  claim 2 , further comprising an insulating layer disposed on the first inclined section and the flat step section of the inclined sidewall to isolate the semiconductor material of the semiconductor die from the RDL. 
     
     
         4 . The semiconductor die of  claim 2 , wherein the RDL includes conductive material forming conductive traces and lead lines connecting the back side of the semiconductor die to the front side of the semiconductor die. 
     
     
         5 . The semiconductor die of  claim 2 , wherein the RDL includes conductive traces and pads formed on the back side of the semiconductor die. 
     
     
         6 . The semiconductor die of  claim 2 , wherein the RDL includes solder balls disposed in a ball grid array (BGA). 
     
     
         7 . The semiconductor die of  claim 2 , wherein the RDL includes at least one of aluminum, copper, and nickel. 
     
     
         8 . The semiconductor die of  claim 1 , wherein the contact pad is a metal contact pad including at least one of aluminum and copper. 
     
     
         9 . The semiconductor die of  claim 1 , wherein the semiconductor device is an optical sensor device and the semiconductor die further comprises an optically active surface area (OASA) disposed on the front side of substrate. 
     
     
         10 . The semiconductor die of  claim 9 , further comprising: a cover glass attached to the front side of the semiconductor die over the optically active surface area disposed on the front side of substrate. 
     
     
         11 . A package, comprising:
 an optical sensor die including an optically active surface area disposed on a front side of a substrate;   a cover glass attached to the front side of the substrate over the optically active surface area disposed on the front side of substrate;   a conductive contact pad embedded in an inter dielectric layer (IDL) disposed on the front side of the substrate, the substrate having an inclined sidewall extending from a back side of the substrate along an edge of the IDL to the front side of the substrate, and the conductive contact pad having a contact pad edge defining a portion of the inclined sidewall; and   a redistribution layer (RDL) disposed on the inclined sidewall, the RDL being physically and electrically connected to the conductive contact pad directly through the contact pad edge defining a portion of the inclined sidewall.   
     
     
         12 . The package of  claim 11 , wherein the inclined sidewall includes a first inclined section extending from the back side toward the front side of the optical sensor die up to the IDL, a flat step section disposed above the conductive contact pad embedded in the IDL disposed on the front side, and a second inclined section extending along the edge of the IDL disposed the front side, the second inclined section being offset from the first inclined section by a width of the flat step section in a direction along the conductive contact pad. 
     
     
         13 . The package of  claim 12 , further comprising an insulating layer disposed on the first inclined section and the flat step section of the inclined sidewall to isolate a semiconductor material of the optical sensor die from the RDL. 
     
     
         14 . The package of  claim 13 , wherein the RDL includes conductive material forming conductive traces and lead lines connecting the back side of the optical sensor die to the front side of the optical sensor die. 
     
     
         15 . The package of  claim 13 , wherein the RDL includes conductive pads formed on the back side of the optical sensor die for placement of solder balls of a ball grid array (BGA). 
     
     
         16 . The package of  claim 15 , further comprising solder balls of a ball grid array (BGA). 
     
     
         17 . A method comprising:
 preparing an assembly of a semiconductor substrate and a cover glass, the semiconductor substrate having an inter dielectric layer (IDL) disposed on a front side thereof, the IDL including a contact pad, the cover glass being bonded to the front side of the semiconductor substrate by a layer of dam material;   etching a trench from a back side of the semiconductor substrate through a semiconductor material of the semiconductor substrate up to the inter dielectric layer (IDL) disposed on the front side of the semiconductor substrate, the trench having a V-shape with inclined sidewalls and having a bottom at the contact pad included in the IDL;   depositing an insulating dielectric layer by chemical vapor deposition on exposed surfaces of the semiconductor substrate including the inclined sidewalls of the trench and the back side of the semiconductor substrate;   depositing a compliant solder mask (CSM) layer on the insulating dielectric layer;   forming a notch through the bottom of the trench to extend the trench through the contact pad, the notch dividing the contact pad into a first contact pad portion and a second contact pad portion with respective contact pad edges aligned with the inclined sidewalls of the trench; and   disposing conductive material in the trench to connect the respective contact pad edges aligned with the inclined sidewalls of the trench to traces or contact pads in a redistribution layer (RDL) disposed on the back side of the semiconductor substrate.   
     
     
         18 . The method of  claim 17 , wherein the semiconductor substrate includes at least two optical sensor devices fabricated therein, and the contact pad included in the IDL is disposed between the at least two optical sensor devices. 
     
     
         19 . The method of  claim 17 , further comprising: disposing a solder mask layer on the RDL disposed on the back side of the semiconductor substrate and patterning the solder mask layer with at least one opening for placement of a solder ball of a ball grid array (BGA). 
     
     
         20 . The method of  claim 19 , further comprising encapsulating at least a portion the assembly in a molding material. 
     
     
         21 . The method of  claim 19 , further comprising singulating the assembly along the trench to isolate or separate an individual package.