Metal working – Means to assemble or disassemble – Means to assemble electrical device
Reexamination Certificate
1999-03-22
2001-04-10
Young, Lee (Department: 3729)
Metal working
Means to assemble or disassemble
Means to assemble electrical device
C029S758000, C007S165000
Reexamination Certificate
active
06212765
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electronics manufacturing and repair, and more particularly, to removing microelectronic components, such as integrated circuits, from substrates on which the microelectronic components are secured.
BACKGROUND OF THE INVENTION
At present, the electronic industry uses hot gas techniques, precise machining techniques and mechanical removal (chiseling) techniques for non-destructively removing microelectronic integrated circuits (IC's) and other similar microelectronic components, such as staked fasteners, from substrates following epoxy cure. The microelectronic components are removed during upgrades, repair and replacement, or substrate substitution or reuse. In some of the microelectronic component systems, the components have screws (staked fasteners) to aid in securing the component to a substrate. Typically, the screws can be secured by epoxy. The edges of the component can also be bonded by an epoxy, making removal difficult because of the epoxy bond. The three removal techniques mentioned above also have drawbacks.
The use of hot gas may heat the integrated circuit or other similar microelectronic component and the substrate to a temperature in excess of 300 C. This could cause damage to the microelectronic component, thus negating any subsequent use of the component or integrated circuit. Additionally, the excessive temperature could damage other similarly positioned microelectronic components, and in the worst case scenario, the substrate itself could be severely damaged, causing an expensive loss of either the substrate or all components mounted on the substrate.
Very precise machining techniques can be exact enough to remove any surrounding, cured epoxy that secures a microelectronic component to the substrate. However, the machining would require, in addition to exact machining tools and methods, a very precise vacuum wand or draw system with sufficient vacuum controls to prevent debris from flying off and damaging any adjacent microelectronic components or integrated circuits.
Mechanical chiseling is difficult because it requires significant force to be exerted on a small, exactly machined chiseling blade. The excess force exacted on the blade to remove the cured epoxy commonly damages neighboring devices. Mechanical removal techniques also require relatively large forces to be exerted against the substrate, which can damage adjacent components and the substrate itself. This would defeat the purpose of reusing the substrate and associated microelectronic components.
There is, therefore, a need to permit non-destructive integrated circuit and similar microelectronic component removal to permit reuse of those components. If these microelectronic components could be removed successfully without damaging the components themselves, then the substrate could also be reused for other applications. This could create an economic benefit when electronic systems are upgraded, repaired and exchanged.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method of removing epoxy bonded integrated circuits and other microelectronic components from a substrate that does not damage the microelectronic component itself, as well as any other adjacent components.
It is still another object of the present invention to provide a method of removing epoxy bonded integrated circuits and similar microelectronic components from a substrate that does not use machining, hot gas or a mechanical chiseling processes.
The present invention is advantageous because it provides a method for removing an epoxy bonded microelectronic component from a substrate without using a hot gas, machining or mechanical chiseling process, but allowing microelectronic component removal without excessive damage. The invention also provides a unique tool that is adapted for removing the microelectronic components from the substrate, such as when the microelectronic component includes screws bonded by epoxy, which aid in securing the components to the substrate.
In accordance with the present invention, the method comprises the steps of removing a microelectronic component from a substrate, wherein the component is bonded around the edges thereof by a cured epoxy. The method includes the steps of heating a removing tool comprising a blade portion, engaging the heated blade portion against cured epoxy position around the edge of the component, and removing the epoxy. The method also comprises positioning the blade portion between an edge of the component and an adjacent portion of the substrate to lift the component from the substrate.
In still another aspect of the present invention, the microelectronic component includes screws bonded by epoxy that aid in securing the microelectronic component to the substrate. In such a structure, a screwdriver receiving tip is attached to the removal tool. The screwdriver receiving tip includes an orifice for receiving a screwdriver shaft. The method further comprises the steps of receiving within the orifice a screwdriver shaft that is freely rotatable therein, and heating the removal tool and thereby heating the screwdriver receiving tip and the screwdriver shaft. The method further comprises heating the screws to be removed with the attached screwdriver shaft and removing the screws by engaging the screwdriver shaft with the screws to be removed, and rotating the screwdriver shaft. The microelectronic component is then removed.
If the microelectronic component has been removed after the screws had been removed, then the screwdriver receiving tip is removed from the removal tool, and a blade portion attached thereto. The removal tool is heated, thereby heating the blade portion. The heated blade portion is engaged against any residual, cured epoxy that remains on the substrate to remove the residual epoxy.
The microelectronic component can typically be bonded around the edges thereof by a cured epoxy. It can include screws bonded by epoxy that aid in securing the microelectronic component to the substrate. In this type of system, the screws are first removed, followed by removal of any epoxy bonding the edges of the microelectronic component. The method further comprises the steps of attaching a screwdriver receiving tip to a removal tool, wherein the screwdriver receiving tip includes an orifice for receiving a screwdriver shaft. The screwdriver shaft is received within the orifice so that it is freely rotatable therein. The removal tool is heated, thereby heating the screwdriver receiving tip and screwdriver shaft.
The screw to be removed is heated with the attached screwdriver shaft. The screw is removed by engaging the screwdriver shaft with the screw and rotating the screwdriver shaft. The screwdriver receiving tip and screwdriver shaft are allowed to cool, and then removed. A blade portion is attached to the removal tool. The removal tool is heated, thereby heating the blade portion. The heated blade portion is positioned against the cured epoxy around the edge of the component and the epoxy removed. The blade portion is then positioned between an edge of the component and adjacent portion of the substrate to lift the component from the substrate.
In still another aspect of the present invention, the epoxy is removed from the blade portion prior to the positioning step. The method further comprises the step of scraping off the epoxy from the substrate by the blade portion and removing the scraped epoxy by vacuum. The vacuum can be applied by a vacuum wand, or the blade portion can include a vacuum channel that connects to a source of vacuum.
In accordance with another aspect of the present invention, a removal tool is provided for removing a microelectronic component from a substrate. The removal tool comprises a body having a proximal handle and a heating end, and a heating element positioned in the removal tool that allows heating at the distal heating end.
A screwdriver receiving tip is removably mounted on the distal heating end of the removal tool. The screwdriver receiving
Beck Donald J.
Bryant Terry S.
Nichols James B.
Fleck Harry M.
Harris Corporation
Jorgenson Frederick R.
Young Lee
LandOfFree
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