Interconnect Strip Mold Shields for Wire Bond-Safe IC Packaging
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Solution Overview
Problem
Existing methods for forming integrated circuit (IC) packages are limited by the need for side gates to control mold compound flow, which restricts the density of interconnects and can damage wire bonds during encapsulation.
Innovation Solution
The use of mold shields arranged in a center region of the interconnect strip, bent to form a right angle or acute angle, which impedes mold compound flow and reduces pressure on wire bonds, allowing for higher density interconnects without side gates and facilitating singulation of IC packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If side gates are used to control mold compound flow, then the encapsulation process can be completed, but the density of interconnects is restricted and wire bonds may be damaged
Solution Approach 1:
The patent removes side gates from the encapsulation process entirely and replaces them with mold shields positioned in the center region of the interconnect strip. This extraction of the harmful element (side gates) eliminates the source of wire bond damage while maintaining encapsulation functionality through the alternative mold shield mechanism.
Solution Approach 2:
Mold shields are introduced as intermediary structures that control mold compound flow without directly contacting or damaging wire bonds. These shields act as mediators between the mold compound and the interconnect components, allowing flow control while protecting sensitive elements like wire bonds from damage.
2Productivity
If side gates are used for mold compound flow control, then encapsulation can proceed, but the number of interconnects per frame is limited
Solution Approach 1:
The mold structure is segmented into multiple mold shields positioned at different locations along the interconnect strip. This segmentation allows independent control of mold compound flow in different regions, enabling higher interconnect density without requiring a single complex side gate structure.
Solution Approach 2:
The patent transitions from side gate control (peripheral dimension) to center region mold shields (central dimension). This dimensional shift in flow control methodology allows mold compound to be directed through the center of the interconnect strip, freeing up peripheral space and enabling higher interconnect density per frame.
3Reliability
If mold compound flows across the entire strip, then encapsulation is complete, but wire bonds in the center region are exposed to excessive pressure
Solution Approach 1:
Mold shields are strategically positioned to provide localized flow control in the center region where wire bonds are located. This creates different flow characteristics in different regions: the center region experiences controlled, reduced pressure due to mold shields, while other regions maintain normal flow for complete encapsulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the number of interconnects in a frame, reduces the risk of damaging wire bonds, and enables the production of more IC packages per strip, such as 154 dual in-line or dual flat no leads packages, by eliminating the need for side gates and ensuring precise singulation.
Implementation Method 1
mold injection pressure causes the mold compound to flow from a first end of the strip of interconnects, across the strip of interconnects to a second end of the strip of interconnects, and the mold shields impede the flow of the mold compound through the regions of the strip of interconnects proximate to the mold shields
Data Source
AI summary
A method for forming integrated circuit (IC) packages includes mounting dies on a strip of interconnects and applying wire bonds in regions of the strip of interconnects proximate to mold shields. The method also includes adjusting the mold shields of the strip of interconnects. The method includes flowing a mold compound on the strip of interconnects to form a strip of IC packages. Mold injection pressure causes the mold compound to flow from a first end of the strip of interconnects across the strip of interconnects to a second end of the strip of interconnects, and the mold shields impede the flow of the mold compound through the regions of the strip of interconnects proximate to the mold shields. The method includes singulating the strip of IC packages to form the IC packages.