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A Dispense System with Magnetic Plunger and Coil to Detect Plunger-Pinning Problems

IP.com Disclosure Number: IPCOM000101734D
Publication Date: 2005-Mar-16
Document File: 3 page(s) / 200K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a plunger made of a ferromagnetic substance and syringe holder with an embedded coil, to monitor the dispensing of polymer materials. Benefits include improving process yield.

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A Dispense System with Magnetic Plunger and Coil to Detect Plunger-Pinning Problems

Disclosed is a method that uses a plunger made of a ferromagnetic substance and syringe holder with an embedded coil, to monitor the dispensing of polymer materials. Benefits include improving process yield.

Background

Currently, most polymer materials used for the assembly process (e.g. liquid underfill, thermal interface material, sealant adhesive etc.) are shipped in a syringe with a plunger and tip-cap (see Figure 1a). These polymer materials are dispensed through a needle connected to the bottom of the syringe; the plunger in the syringe is pressed downward with air-pressure (see Figure 1b). However, often plunger-pinning occurs, where the plunger cannot be displaced within the syringe. This is caused by air passing around the plunger due to excessive air pressure (see Figure 1c), or by foreign particles / large fillers inside the polymer material that clog the needle (see Figure 1d).

So far there is no method to detect the plunger-pinning problem directly.

General Description

The disclosed method uses electromotive force (via a magnetic plunger and coil) to dispense a fixed amount of polymer material for each package. The disclosed method uses a plunger made from a ferromagnetic substance, and a coil surrounding a syringe that is embedded in a syringe holder (see Figure 2 as example applied for underfill process).

Electromotive force arises at the coil when the magnetic plunger is pushe...