Integrated circuit wafer packaging system and method

Abstract

A packaging system, hereinafter referred to as the Critical Packaging System, relates to critical issues that associate with sensitive articles such as IC wafers before, during and after shipment phases. The system employs a choice of two or more specialty designed containers, and any one selected design having choices of two or more methods by which to avoid, reduce and / or eliminate wafer damage from breakage, scratches and / or corrosion during shipment phases. For the purpose of maximizing product yield during packaging phases a special apparatus is used to insert wafers within containers without scratch damage. The following programs are used in packaging: (1) Quality Assurance / Certification, (2) Critical Factor Monitoring, and (3) a Recycle and Refurbish Program. These programs are specifically designed to achieve new levels of product yields, reduce product cost, and landfill impact.

Description

FIELD OF THE INVENTION [0001] The invention relates to semiconductor wafer packaging and transportation system, and more particularly to a packaging system and method of packaging sensitive articles such as semiconductor wafers to prevent damage to the wafers before, during and after storage / shipment phases. BACKGROUND OF THE INVENTION [0002] To date, the semiconductor industry has been able to produce IC wafers increasing functional capabilities and increasing density without necessarily suffering losses during the transport processes, or at least having not realized the packaging media as a source for those losses. In general, present day transport media designed for packaging IC wafers are lacking the necessary features to address several problems common to advanced technology wafers during insertion and transport. This is especially true for 21st Century wafers higher speed with smaller geometries (and having elevated interconnect members including bond pads, caps, and balls. Th...

AI Technical Summary

Benefits of technology

The CPS significantly reduces wafer damage, increases product yields, and optimizes protection during shipment by eliminating motion-induced scratches, absorbing shock energy, and minimizing corrosive contamination, thereby enhancing the reliability of semiconductor wafers.

Problems solved by technology

In general, present day transport media designed for packaging IC wafers are lacking the necessary features to address several problems common to advanced technology wafers during insertion and transport.

These problems can manifest themselves in the form of disfigured connectors that include wafer breakage, scratch damage as well as mobile ion induced parametric failures.

Wafer shipping containers / boxes in combination with bags, outer cardboard type boxes, cushions and separators that are not functionally coordinated nor objectively systematized to address wafer movement, Airborne Molecular Contaminants (AMCs), and vapor leakage during transport can cause yield problems to the semiconductor wafers.

The resulting wafer movement, when combined with wafers that utilize soft thin protective overcoats and elevated soft pads, caps and / or ground rings, can result in scratching during the wafer insertion and transport process.

Stacked wafers with elevated features may also transfer structural damage to other associated wafers if improper materials are selected with too soft or too stiff a compressibility factor.

Partial loading of a box changes the compressibility requirements of the system so that simply adding more cushions may not be the most appropriate solution.

These contaminates may lead to corrosive damage and / or transistor inversion.

AMCs are exceptionally small in size they are generally corrosive and they carry a charge.

Through molecular migration, a charge build may occur over an active transistor node resulting in transistor inversion and a parametric failure.

There will be no clear path leading back to the transport media system as a source of the problem.

The impact, depending on the weight of the wafer and the amount of trapped air, will result in some amount of uneven force as the two surfaces come in contact with each other.

The allowed lateral movement during the insertion will result in scratch damage.

Nor is it understood if this sub-micron crazing can later become a point of entry for corrosive growth.

It is known that such damage has been witnessed at the bevel edges of the wafers.

Scratch Damage: Smeared or Scratched Circuit Lead Scratches

During transport, lateral movement of wafers within containers / boxes will scratch wafer surfaces during shipment.

The resulting scratches will cause damage to interconnect circuitry including smashing and disfiguring elevated connecting members such as ground rings, ball bond pads, and caps.

The same lateral movement will also create shaving from the protective separators which further promotes scratch damage.

Corrosive damage to wafer surfaces is generally caused by packaging materials such as containers, bags, cushions and separators that out-gas or chemically deplete excessive Airborne Molecular Contaminants or AMCs.

Therefore, moisture barrier bags having a high Moisture Vapor Transmission Rate or MVTR when combined with excessive AMCs will create corrosive residues causing latent defects to wafer surfaces.

Assuming no cracks or crazing have occurred to the passivation, the charge build that gathers above the transistor node may result in the transistor inverting, leading to a parametric circuit failure.

Generally these AMCs have already attached themselves to the oxide so that saw and grind slurry and their respective cleanups accomplish little to achieve removal.

For wafers packaged within shipping containers, there are instances where bond pads and adjacent passivation coatings will accumulate contamination that appears as a stain.

Clean rooms are teeming with AMCs that cannot be effectively removed by HEPA filters.

A small amount of chemical reaction takes place with the exposed aluminum or copper surface, thereby resulting in a corrosive stain in the area of bond pads as well as in any area where a mismatch between the photo-resist and the PO coating occurs.

Surfaces of bond pads that become excessively corroded while in transit from one location to another may become unnecessarily exposed to the condition of AMCs.

This damage is normally restricted to bond pad surfaces only and normally is associated with the presence of moisture vapors.

This out-gassing may be linked to inorganic and organic type AMCs resulting in the corrosive damage.

Poor selection of packaging materials such as open cell foam cushions and / or wafer separators treated with chemical additives that out-gas AMCs when combined with moisture vapors can cause bond pads to become contaminated.

Present-day packaging technology can cause wafers to be damaged by cushion over-packaging and / or under-packaging.

Wafer damage due to over-packaging is identified as resulting from stress-energy and will result in breakage usually during the packing process as the wafer box lid is attached or if the container is mishandled after closure.

Wafers damaged due to under-packaging can be caused by shock-energy if the container receives a sudden impact.

Both of these type failures may also be impacted by the size and thickness of the wafer and the resulting ability to withstand these kinds of forces.

HEPA filtration like that used in most front ends does not remove AMCs from the environment.

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