Stackable Semiconductor Package Supporting Element

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Solution Overview

Problem

Conventional stackable semiconductor packages face issues with the overhang portion of the second substrate shaking, swaying, or cracking during wire bonding, limiting the layout space and overall thickness reduction due to excessive stress and overhang length constraints.

Innovation Solution

Incorporation of a supporting element between the first and second substrates to stabilize the overhang portion, allowing for increased area and reduced thickness by using a molding compound or resin material to support the second substrate, preventing sway and crack occurrences during wire bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the second substrate has a large area to increase layout space, then more devices can be disposed on the second substrate, but the overhang portion becomes longer and causes sway, shake, or crack during wire bonding

Engineering Contradiction:

Improvearea of the second substrateVSAvoidstability of the overhang portion

Core Design Contradiction:

Area of stationary objectVSStability of the object's composition

Solution Approach 1:

A supporting element is introduced as an intermediary component between the first substrate and the second substrate. This supporting element provides mechanical support to the overhang portion of the second substrate, preventing sway and shake during wire bonding while allowing the second substrate to maintain its large area for increased layout space.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of stationary object

If the second substrate is made thinner to reduce overall package thickness, then the overall thickness of the package is reduced, but the overhang portion becomes more prone to crack under stress

Engineering Contradiction:

Improvethickness of the second substrateVSAvoidstrength of the overhang portion

Core Design Contradiction:

Length of stationary objectVSStrength

Solution Approach 1:

The supporting element acts as a mediator that distributes and reduces the stress on the thin second substrate. By providing additional structural support underneath the overhang portion, the supporting element allows the second substrate to be made thinner while preventing cracks from forming during wire bonding operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Length of moving object

If the overhang length is limited to prevent sway and crack, then wire bonding stability is improved, but the area of the second substrate is restricted

Engineering Contradiction:

Improveoverhang lengthVSAvoidarea of the second substrate

Core Design Contradiction:

Length of moving objectVSArea of stationary object

Solution Approach 1:

The supporting element serves as a mediator that decouples the relationship between overhang length and structural stability. It provides the necessary mechanical support to allow longer overhangs without sway or crack, thereby enabling the second substrate to have a larger area for device placement.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Strength

If the second substrate is made thicker to prevent crack, then structural integrity is improved, but the overall thickness of the package increases

Engineering Contradiction:

Improvestrength of the second substrateVSAvoidoverall thickness of the package

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

The structural support function is segmented from the second substrate itself and transferred to a separate supporting element. This allows the second substrate to be made thinner for reduced package thickness while the supporting element provides the necessary strength to prevent cracks during wire bonding.

Inventive Principle:

Principle #1Segmentation

5Area of stationary object

If the overhang portion is supported to allow longer overhang, then layout space is increased, but the complexity of the package structure increases

Engineering Contradiction:

Improvelayout space on the second substrateVSAvoidcomplexity of the package structure

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The supporting element is designed to perform multiple functions: it provides mechanical support to the overhang portion, distributes stress during wire bonding, and enables larger substrate area. This multi-functionality justifies the added component while delivering significant benefits in layout space and reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7589408B2Stackable semiconductor package

Publication Date: 2009.09.15 ADVANCED SEMICON ENG INC

AI summary

A stackable semiconductor package includes first and second substrates, a semiconductor device, first wires, a supporting element, and a first molding compound. The semiconductor device is disposed on the first substrate. The second substrate is disposed above the semiconductor device, and the area of the second substrate is larger than that of the semiconductor device. The first wires electrically connect the first and second substrates. The supporting element is disposed between the first and second substrates, and supports the second substrate. Some pads of the second substrate are exposed outside the first molding compound. Therefore, the overhang portion of the second substrate will not shake or sway during wire bonding, and the area of the second substrate can be increased to have more devices thereon. Also, the thickness of the second substrate can be reduced, to reduce the overall thickness of the stackable semiconductor package.