Optically interactive device packages and methods of assembly

Abstract

An image sensor package and methods for simultaneously fabricating a plurality of such packages. A layer of barrier material comprising a matrix of raised walls is formed around chip attachment areas located in an array on a carrier substrate to create chip cavities. Image sensor chips are wire bonded within the chip cavities, and a unitary transparent cover is sealed in place over the entire assembly. The resultant image sensor package array is then singulated along lines running between the chip attachment areas and in parallel to the raised walls to provide individual image sensor packages. The layer of barrier material may be formed directly on the carrier substrate by molding methods or by depositing a series of curable layers of liquid or flowable material in a stacked fashion. Alternatively, the layer of barrier material may be preformed as a unitary frame and then secured to the carrier substrate.

What is claimed is:  
     
         1 . A method for simultaneously fabricating a plurality of packaged optically interactive electronic devices, comprising: 
 providing a carrier substrate having an array of device attachment areas on a surface thereof, each of the device attachment areas comprising a chip attachment surface and at least one associated wire bonding location in communication with at least one conductive trace on the carrier substrate;    forming a layer of barrier material having an array of apertures therethrough on the surface of the carrier substrate, each of the apertures exposing the chip attachment surface and the at least one associated wire bonding location of one of the device attachment areas to form an array of chip cavities;    attaching an optically interactive electronic device having at least one bond pad on an active surface thereof to the chip attachment surface in at least one chip cavity of the array of chip cavities;    forming a wire bond between the at least one bond pad on the active surface of the optically interactive electronic device and the at least one associated wire bonding location in the at least one chip cavity;    covering the layer of barrier material with a unitary transparent cover having dimensions substantially equal to dimensions of the carrier substrate to form a package array; and    separating the package array along lines extending between the device attachment areas to form a plurality of individual optically interactive electronic device packages.    
     
     
         2 . The method according to  claim 1 , wherein forming a layer of barrier material comprises: 
 molding a contiguous matrix of raised walls onto the surface of the carrier substrate with a mold compound supplied to a molding tool in sealing engagement with the surface of the carrier substrate.    
     
     
         3 . The method according to  claim 2 , wherein molding a contiguous matrix of raised walls comprises using one of the group consisting of transfer molding, injection molding and pot molding.  
     
     
         4 . The method according to  claim 2 , wherein the mold compound is selected to comprise a polymer mold compound.  
     
     
         5 . The method according to  claim 4 , further comprising adding a filler material to the polymer mold compound prior to molding the contiguous matrix of raised walls.  
     
     
         6 . The method according to  claim 5 , wherein the filler material is selected to comprise silicon particles.  
     
     
         7 . The method according to  claim 1 , wherein forming a layer of barrier material comprises forming a contiguous matrix of raised walls by: 
 dispensing a layer of flowable material onto the surface of the carrier substrate;    curing the flowable material to form a first hardened layer and, optionally: 
 dispensing at least one additional layer of flowable material over the first hardened layer; and  
 curing the at least one additional layer of flowable material.  
   
     
     
         8 . The method according to  claim 7 , wherein the flowable material is selected from the group consisting of a mold compound, an activated epoxy, a thermoplastic resin material and a thermoset resin material.  
     
     
         9 . The method according to  claim 1 , wherein forming a layer of barrier material comprises forming a contiguous matrix of raised walls by: 
 placing the carrier substrate in a reservoir at a first point below a surface of a curable liquid contained in the reservoir;    exposing a selected volume of the curable liquid to an activating agent to form a first layer of hardened material on the surface of the carrier substrate and, optionally: 
 lowering the carrier substrate to at least one additional point below the surface of the curable liquid; and  
 exposing at least one additional selected volume of the curable liquid to the activating agent over the first layer of hardened material.  
   
     
     
         10 . The method according to  claim 9 , wherein the curable liquid is selected to comprise a photocurable liquid and the activating agent is selected to comprise a beam of electromagnetic radiation.  
     
     
         11 . The method according to  claim 9 , wherein the curable liquid is selected from the group consisting of a liquid polymer and a liquid resin material.  
     
     
         12 . The method according to  claim 1 , wherein forming a layer of barrier material comprises: 
 preforming a unitary frame; and    securing the unitary frame to the surface of the carrier substrate.    
     
     
         13 . The method according to  claim 12 , wherein preforming a unitary frame comprises molding the unitary frame with a mold compound using one of the group consisting of transfer molding, injection molding and pot molding.  
     
     
         14 . The method according to  claim 13 , wherein the mold compound is selected to comprise a polymer mold compound.  
     
     
         15 . The method according to  claim 14 , further comprising adding a filler material to the polymer mold compound prior to molding the unitary frame.  
     
     
         16 . The method according to  claim 15 , wherein the filler material is selected to comprise silicon particles.  
     
     
         17 . The method according to  claim 12 , wherein preforming a unitary frame comprises selectively removing material from a sheet of material.  
     
     
         18 . The method according to  claim 12 , wherein securing the unitary frame to the surface of the carrier substrate comprises securing the unitary frame to the surface with an adhesive material.  
     
     
         19 . The method according to  claim 18 , wherein the adhesive material is selected from the group consisting of a liquid epoxy adhesive, an acrylic adhesive, a two-component resin adhesive and a double-sided adhesive-coated tape.  
     
     
         20 . The method according to  claim 1 , wherein covering the layer of barrier material with a unitary transparent cover comprises sealing the unitary transparent cover to the layer of barrier material with a layer of adhesive material.  
     
     
         21 . The method according to  claim 20 , wherein the layer of adhesive material is selected from the group consisting of a liquid epoxy adhesive, a silicone adhesive, an acrylic adhesive, a two-component resin adhesive and a double-sided adhesive-coated tape.  
     
     
         22 . The method according to  claim 1 , wherein covering the layer of barrier material with a unitary transparent cover comprises sealing the unitary transparent cover to the layer of barrier material using one of the group consisting of thermal bonding and pressure bonding.  
     
     
         23 . The method according to  claim 1 , wherein the unitary transparent cover is selected from the group of materials consisting of glass, quartz and plastic.  
     
     
         24 . The method according to  claim 23 , wherein the unitary transparent cover is selected to be borosilicate glass.  
     
     
         25 . The method according to  claim 1 , further comprising: 
 filling the at least one chip cavity with a transparent encapsulant material prior to covering the layer of barrier material with the unitary transparent cover; and    sealing the unitary transparent cover to the layer of barrier material.    
     
     
         26 . The method according to  claim 1 , further comprising: 
 dimensioning the unitary transparent cover to be slightly smaller than dimensions of the carrier substrate;    forming a raised lip around a perimeter of the layer of barrier material; and    aligning the unitary transparent cover over the layer of barrier material within the raised lip.    
     
     
         27 . The method according to  claim 26 , wherein forming a raised lip around the perimeter of the layer of barrier material comprises forming the raised lip integrally with the layer of barrier material.  
     
     
         28 . The method according to  claim 1 , wherein separating the package array comprises cutting the package array with a saw.  
     
     
         29 . The method according to  claim 1 , wherein separating the package array comprises scoring at least one surface of the package array and snapping the package array into individual pieces.  
     
     
         30 . The method according to  claim 1 , wherein the optically interactive electronic device is selected to comprise a solid-state image sensor.  
     
     
         31 . The method according to  claim 1 , further comprising: 
 forming at least one castellated solder pad in communication with the at least one conductive trace on an edge of at least one of the individual optically interactive electronic device packages.    
     
     
         32 . The method according to  claim 1 , further comprising: 
 attaching at least one discrete conductive element in communication with the at least one conductive trace to a bottom side of the carrier substrate.    
     
     
         33 . The method according to  claim 32 , wherein the at least one discrete conductive element is attached to the bottom side of the carrier substrate prior to separating the package array.  
     
     
         34 . An optically interactive electronic device package array comprising: 
 a carrier substrate having an array of device attachment areas on a surface thereof, each of the device attachment areas comprising a chip attachment surface and at least one associated wire bonding location in communication with at least one conductive trace on the carrier substrate;    a layer of barrier material having an array of apertures therethrough secured to the surface of the carrier substrate, each of the apertures exposing the chip attachment surface and the at least one associated wire bonding location of one of the device attachment areas to form an array of chip cavities;    an optically interactive electronic device having at least one bond pad on an active surface thereof attached to the chip attachment surface in at least one chip cavity;    a wire bond connecting the at least one bond pad on the active surface of the optically interactive electronic device and the at least one associated wire bonding location in the at least one chip cavity; and    a unitary transparent cover having dimensions substantially equal to those of the carrier substrate sealed to a top surface of the layer of barrier material.    
     
     
         35 . The optically interactive electronic device package array of  claim 34 , wherein the layer of barrier material comprises a contiguous matrix of raised walls attached directly to the surface of the carrier substrate.  
     
     
         36 . The optically interactive electronic device package array of  claim 35 , wherein the contiguous martrix of raised walls comprises a polymer mold compound.  
     
     
         37 . The optically interactive electronic device package array of  claim 36 , further comprising: 
 a filler material incorporated within the polymer mold compound.    
     
     
         38 . The optically interactive electronic device package array of  claim 37 , wherein the filler material comprises silicon particles.  
     
     
         39 . The optically interactive electronic device package array of  claim 34 , wherein the layer of barrier material comprises a contiguous matrix of raised walls formed of a plurality of stacked layers of cured material.  
     
     
         40 . The optically interactive electronic device package array of  claim 39 , wherein the plurality of stacked layers is formed of one of the group consisting of a mold compound, an activated epoxy and a resin material.  
     
     
         41 . The optically interactive electronic device package array of  claim 39 , wherein the plurality of stacked layers is formed of a photocured material.  
     
     
         42 . The optically interactive electronic device package array of  claim 41 , wherein the photocured material is one of the group consisting of a photocured polymer and a photocured resin material.  
     
     
         43 . The optically interactive electronic device package array of  claim 34 , further comprising: 
 a layer of adhesive material between the surface of the carrier substrate and the layer of barrier material.    
     
     
         44 . The optically interactive electronic device package array of  claim 43 , wherein the layer of adhesive material is one of the group consisting of an epoxy adhesive, an acrylic adhesive, a two-component adhesive resin and a double-sided adhesive-coated tape.  
     
     
         45 . The optically interactive electronic device package array of  claim 43 , wherein the layer of barrier material is a unitary frame formed of a mold compound.  
     
     
         46 . The optically interactive electronic device package array of  claim 45 , further comprising: 
 a filler material incorporated within the mold compound.    
     
     
         47 . The optically interactive electronic device package array of  claim 46 , wherein the filler material comprises silicon particles.  
     
     
         48 . The optically interactive electronic device package array of  claim 43 , wherein the layer of barrier material is a unitary frame comprising a solid sheet of material having apertures formed therein.  
     
     
         49 . The optically interactive electronic device package array of  claim 34 , further comprising: 
 a layer of adhesive material between a top surface of the layer of barrier material and the unitary transparent cover.    
     
     
         50 . The optically interactive electronic device package array of  claim 49 , wherein the layer of adhesive material is one of the group consisting of an epoxy adhesive, a silicone adhesive, an acrylic adhesive, a two-component resin and a double-sided adhesive-coated tape.  
     
     
         51 . The optically interactive electronic device package array of  claim 34 , wherein the unitary transparent cover is formed of one of the group consisting of glass, quartz and plastic.  
     
     
         52 . The optically interactive electronic device package array of  claim 34 , wherein the unitary transparent cover is formed of borosilicate glass.  
     
     
         53 . The optically interactive electronic device package array of  claim 34 , further comprising: 
 a transparent encapsulant material filling a space in the at least one chip cavity between the active surface of the optically interactive electronic device and the unitary transparent cover.    
     
     
         54 . The optically interactive electronic device package array of  claim 34 , further comprising: 
 a raised lip around a perimeter of the top surface of the layer of barrier material and abutting an outside edge of the unitary transparent cover.    
     
     
         55 . The optically interactive electronic device package array of  claim 54 , wherein the raised lip is integrally formed with the layer of barrier material.  
     
     
         56 . The optically interactive electronic device package array of  claim 34 , wherein the optically interactive electronic device comprises a solid-state image sensor.  
     
     
         57 . The optically interactive electronic device package array of  claim 34 , further comprising: 
 at least one discrete conductive element attached to the carrier substrate on a surface thereof opposite the surface bearing the device attachment areas and in communication with the at least one conductive trace.