Method for attaching a semiconductor die to a leadframe using a patterned adhesive layer
First Claim
1. A method of attaching a semiconductor die formed with a plurality of bonding pads to a leadframe having a plurality of continuous metal lead fingers adapted to extend across a surface of the die for attachment to the bonding pads using fine bond wires, comprising:
- depositing an adhesive selected from the group consisting of thermoplastic adhesives or thermosetting adhesives on the die and patterning the adhesive to form a preapplied patterned adhesive layer on a surface of the die with the bonding pads of the die free of adhesive;
heating the adhesive layer during a packaging process; and
pressing the die, heated adhesive layer and lead fingers of the leadframe together during the packaging process to bond the adhesive layer and lead fingers and attach the lead fingers to the die.
2 Assignments
0 Petitions
Accused Products
Abstract
An improved method for attaching a semiconductor die to a leadframe is provided The improved method comprises forming a patterned adhesive layer on a side of a semiconductor wafer prior to singulation of the dies from the wafer. The adhesive layer is patterned such that wire bonding pads on the dies, as well as the streets between the dies, are free of adhesive material The adhesive layer may be deposited and patterned using a hot or cold screen printing process, by depositing and photopatterning a photosensitive adhesive, or using a resist etch back method. During a packaging process for attaching a die to a leadframe, the adhesive layer is heated and the lead fingers of the leadframe are placed in contact with the die under pressure. In an alternate embodiment of the invention, the lead fingers, rather than a side of the dies, are coated with an adhesive layer.
-
Citations
22 Claims
-
1. A method of attaching a semiconductor die formed with a plurality of bonding pads to a leadframe having a plurality of continuous metal lead fingers adapted to extend across a surface of the die for attachment to the bonding pads using fine bond wires, comprising:
-
depositing an adhesive selected from the group consisting of thermoplastic adhesives or thermosetting adhesives on the die and patterning the adhesive to form a preapplied patterned adhesive layer on a surface of the die with the bonding pads of the die free of adhesive; heating the adhesive layer during a packaging process; and pressing the die, heated adhesive layer and lead fingers of the leadframe together during the packaging process to bond the adhesive layer and lead fingers and attach the lead fingers to the die. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. In semiconductor manufacture a method for attaching a semiconductor die to a leadframe, having a plurality of continuous metal lead fingers, said method comprising:
-
forming a semiconductor wafer with a plurality of semiconductor dies having bond pads electrically connected to integrated circuits; coating a side of the wafer and dies with an adhesive selected from the group consisting of thermoplastic or thermosetting adhesives and patterning the adhesive to form a patterned adhesive layer on the wafer with the bond pads free of adhesive; separating the dies from the wafer; heating the patterned adhesive layer during a packaging process; pressing the lead fingers of the leadframe to a side of the adhesive coated die during the packaging process to bond the adhesive layer and leadframe and attach the lead fingers to the die; and continuing the packaging process. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. The method as claimed in claim 19 and wherein the adhesive layer is formulated to function as an insulating/passivating layer for the wafer.
-
20. A method for attaching a semiconductor die to a leadframe for a semiconductor package, comprising:
-
providing a leadframe having a plurality of continuous lead fingers adapted to extend over a side of the die; applying an adhesive selected from the group consisting of thermoplastic adhesives or thermosetting adhesives to an underside of the lead fingers in a pattern that matches a placement of the lead fingers over the die to form a preapplied patterned adhesive layer; heating the patterned adhesive layer during a packaging process; and pressing the lead fingers, adhesive layer and die together to bond the adhesive layer and die and attach the lead fingers to the die. - View Dependent Claims (21, 22)
-
Specification