Browse Prior Art Database

Method to Attach Ultra Thin Die to PWB Using a Vacuum Chuck

IP.com Disclosure Number: IPCOM000004590D
Original Publication Date: 2001-Feb-23
Included in the Prior Art Database: 2001-Feb-23
Document File: 2 page(s) / 41K

Publishing Venue

Motorola

Related People

Andrew Skipor: AUTHOR [+4]

Abstract

Lower semiconductor package thickness and less weight are among the significant benefits of using ultra-thin die. The methodology used today to assemble circuits with ultra-thin die is both time and labor-intensive. A high-volume technique for assembling circuits with ultra-thin die is proposed.

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Method to Attach Ultra Thin Die to PWB Using a Vacuum Chuck

By Andrew Skipor, Daniel Gamota, Krishna Kalyanasundaram, and Steve Schiefers

SUMMARY

Lower semiconductor package thickness and less weight are among the significant benefits of using ultra-thin die. The methodology used today to assemble circuits with ultra-thin die is both time and labor-intensive. A high-volume technique for assembling circuits with ultra-thin die is proposed.

PROBLEM

Reduction in wafer thickness has increased the opportunities for miniaturization of portable electronics. Ultra-thin die provide the same functionality of standard thick die, while allowing for reduction of semiconductor package thickness and weight. The current methodology to handle die consists of an end effector that has discrete vacuum ports. This methodology works very well for handling die of standard wafer thickness. However, due to the inherent fragility of the ultra-thin die, this methodology results in die breakage and hence, cannot be used (Fig. 1).

SOLUTION

An end effector comprised of a labyrinth of interconnected cells is proposed to handle ultra-thin die effectively (Fig. 2). The size of the end effector is matched to the size of the ultra-thin die to maximize yield during handling. The end effector can be made using a porous, machineable material such as porous ceramic. Vacuum is applied to the input nozzle of the end effector while it is lowered over the diced ultra-thin wafer that is supported by a wafer tape (Fig. 3). The wafer support tape can be either a heat release or a UV-release tape. Exposing the wafer support tape under the die to either heat or UV radiation reduces the adhesion between the tape and the ultra-thin die. This facilitates the die pick up. The end effector then aligns the die using the features on the die and the circuit board (such as fiducials, bumps), and a camera system. It then places the ultra-thin die on the circuit board.

The end effector can be mounted to a standard pick and place machine with minimal modifications. This solution enables the assembly of ultra-thin die attachment to circuit boards.