Pre-molded integrated circuit packages

Abstract

A leadframe with pre-molded cavities includes an outer frame and a plurality of units. Each unit includes a die pad and a plurality of leads. For each unit, a molding compound extends over a first portion of an upper surface of each of the leads that is located farthest from the die pad. The molding compound may also extend over an upper surface of the die pad. A second portion of the upper surface of each of the plurality of leads that is located nearest the die pad remains exposed outside the molding compound. A thickness of the molding compound covering the first portion of the upper surface of each of the leads is greater than a thickness of the molding compound covering the upper surface of the die pad.

1 .- 8 . (canceled) 
     
     
         9 . A method of forming a pre-molded cavity over a die pad that is surrounded by a plurality of leads, an upper surface of each of the plurality of leads having a closest portion nearest the die pad, a farthest portion farthest from the die pad, and a middle portion between the closest portion and the farthest portion, the method comprising:
 placing an insert over each of the plurality of leads, the insert having a bottom surface that contacts the closest portion of the upper surface of each of the plurality of leads, the insert also having a cutout above the middle portion of the upper surface of each of the plurality of leads so that the insert does not contact the middle portion of the upper surface;   forming a first molded portion that extends over the farthest portion of the upper surface of each of the plurality of leads, the first molded portion surrounding the die pad to form the cavity over the die pad, where the insert prevents formation of the first molded portion over the closest portion and the middle portion of the upper surface of each of the plurality of leads; and   removing the insert to expose the closest portion and the middle portion of the upper surface of each of the plurality of leads.   
     
     
         10 . The method of  claim 9  wherein the closest portion and the farthest portion of the upper surface of each of the plurality of leads surround the middle portion of the upper surface of each of the plurality of leads. 
     
     
         11 . The method of  claim 9  further comprising:
 forming a second molded portion that extends over the die pad, where a thickness of the first molded portion is greater than a thickness of the second molded portion. 
 
     
     
         12 . The method of  claim 9  wherein edges of the die pad and edges of the plurality of leads have a step-shaped profile so that an area of an upper surface of the die pad is larger than an area of a lower surface of the die pad and an area of the upper surface of each of the plurality of leads is greater than an area of a lower surface of each of the plurality of leads, the method further comprising forming a second molded portion that covers the edges of the die pad and the edges of the plurality of leads. 
     
     
         13 . The method of  claim 9  further comprising:
 placing a semiconductor die in the cavity over the die pad, the semiconductor die having a plurality of bond pads thereon; 
 attaching a bonding wire from each bond pad of the plurality of bond pads to a corresponding lead of the plurality of leads, where the bonding wire is attached to the middle portion of the upper surface of the lead; and 
 covering the semiconductor die and filling at least a portion of the cavity over the die pad with a gel encapsulant. 
 
     
     
         14 . The method of  claim 13  wherein the gel encapsulant covers the closest portion and the middle portion of the upper surface of each lead. 
     
     
         15 . A method of forming a pre-molded cavity over each of a plurality of die pads of a leadframe, wherein the pre-molded cavity over each of the plurality of die pads is formed using the method of  claim 9 . 
     
     
         16 .- 20 . (canceled) 
     
     
         21 . A method of forming a pre-molded cavity over a die pad that is surrounded by a plurality of leads, an upper surface of each of the plurality of leads having a closest portion nearest the die pad, a farthest portion farthest from the die pad, and a middle portion between the closest portion and the farthest portion, the method comprising:
 placing an insert over each of the plurality of leads, the insert having a bottom surface that contacts the closest portion of the upper surface of each of the plurality of leads, the insert also having a cutout above the middle portion of the upper surface of each of the plurality of leads so that the insert does not contact the middle portion of the upper surface;   forming a first molded portion that extends over the farthest portion of the upper surface of each of the plurality of leads, the first molded portion surrounding the die pad to form the cavity over the die pad, where the insert prevents formation of the first molded portion over the closest portion and the middle portion of the upper surface of each of the plurality of leads;   forming a second molded portion that extends over an upper surface of the die pad and covers edges of the die pad and edges of the plurality of leads; and   removing the insert to expose the closest portion and the middle portion of the upper surface of each of the plurality of leads.   
     
     
         22 . The method of  claim 21  wherein a thickness of the first molded portion is greater than a thickness of the second molded portion. 
     
     
         23 . The method of  claim 21  wherein the closest portion and the farthest portion of the upper surface of each of the plurality of leads surround the middle portion of the upper surface of each of the plurality of leads. 
     
     
         24 . The method of  claim 21  wherein the edges of the die pad and the edges of the plurality of leads have a step-shaped profile so that an area of the upper surface of the die pad is larger than an area of a lower surface of the die pad and an area of the upper surface of each of the plurality of leads is greater than an area of a lower surface of each of the plurality of leads. 
     
     
         25 . A method of forming a pre-molded cavity over each of a plurality of die pads of a leadframe, wherein the pre-molded cavity over each of the plurality of die pads is formed using the method of  claim 21 . 
     
     
         26 . A method of forming a pre-molded cavity over a die pad that is surrounded by a plurality of leads, an upper surface of each of the plurality of leads having a closest portion nearest the die pad, a farthest portion farthest from the die pad, and a middle portion between the closest portion and the farthest portion, the method comprising:
 using an insert to form a first molded portion that extends over the farthest portion of the upper surface of each of the plurality of leads, the first molded portion surrounding the die pad to form the cavity over the die pad, where the insert prevents formation of the first molded portion over the closest portion and the middle portion of the upper surface of each of the plurality of leads; and   using the insert to form a second molded portion that extends over an upper surface of the die pad and covers edges of the die pad and edges of the plurality of leads, wherein a thickness of the first molded portion is greater than a thickness of the second molded portion.   
     
     
         27 . The method of  claim 26  wherein the insert has a bottom surface that contacts the closest portion of the upper surface of each of the plurality of leads and also has a cutout above the middle portion of the upper surface of each of the plurality of leads so that the insert does not contact the middle portion of the upper surface. 
     
     
         28 . The method of  claim 26  wherein the closest portion and the farthest portion of the upper surface of each of the plurality of leads surround the middle portion of the upper surface of each of the plurality of leads. 
     
     
         29 . The method of  claim 26  wherein the edges of the die pad and the edges of the plurality of leads have a step-shaped profile so that an area of the upper surface of the die pad is larger than an area of a lower surface of the die pad and an area of the upper surface of each of the plurality of leads is greater than an area of a lower surface of each of the plurality of leads. 
     
     
         30 . A method of forming a pre-molded cavity over each of a plurality of die pads of a leadframe, wherein the pre-molded cavity over each of the plurality of die pads is formed using the method of  claim 26 .