Amkor Technology, Inc.

Amkor Electronics, Inc.

Anam Industrial Co., Ltd.

John Briar

Bruce J Freyman

Jack C Maxcy

Young Wook Heo

Il Kwon Shim

A grid array assembly is provided employing a thin copper or steel carrier frame having apertures extending longitudinally of the frame. A series of semi-flexible substrate printed circuit boards are mounted in seriatim to peripheral edges of the apertures, the circuit boards including bonding pads and metallization on a first surface and conductive vias in the circuit boards extending to a second opposite surface containing a contact pad array. The carrier strip with the mounted circuit boards are passed to a station where an IC die is mounted on the board first surface, wire bonds are placed from the die to the bonding pads and the assembly encapsulated using a portion of the carrier strip as a mold gate to form a package body. Subsequently each grid array assembly is singulated from the carrier strip.

Grid array assembly of circuit boards with singulation grooves

A grid array assembly method uses a semi-flexible substrate printed circuit board and includes steps of providing a series of conforming boards each board including bonding pads and metallization on a first surface and conductive vias in the board extending to a second opposite surface containing a contact pad array, testing the boards and determining acceptable boards. A carrier strip with longitudinally aligned apertures mounts individual accepted boards. The strip with mounted boards is passed to a station where an IC die is mounted on the board first surface, wire bonds are placed from the die to the bonding pads and the assembly encapsulated by automolding against a board first surface portion using the strip as the mold gate to form a package body. Subsequently interconnecting balls or bumps are placed on the contact pads and the assembly is removed from the strip.

Method of making grid array assembly

According to the invention, an electronic device mounted on a substrate is encapsulated using a standard two-piece mold. A novel degating region is formed on a surface of the substrate to allow removal of excess encapsulant formed on the surface during molding without damaging the remainder of the device. The material of the degating region that contacts the encapsulant forms a weak bond with the encapsulant, relative to the bond formed between the encapsulant and the substrate, so that the encapsulant can be peeled away from the degating region without damaging the substrate or other portion of the device. The degating region is provided without introducing additional steps into the process for forming the device. The presence of the degating region eliminates the necessity of using a three-piece or modified two-piece mold to achieve top gating in order to degate without damaging the device. In one embodiment, the degating region is made of gold. Gold has an adhesive force with typical encapsulant materials that is approximately 10% of the adhesive force between the typical encapsulant materials and typical substrate materials.

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Phoenix, AZ, United States of America

John Briar