LGA Housing Injection Molding with Silicone Encapsulation
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Solution Overview
Problem
Miniaturized sensor circuits face challenges in second-level packaging due to high pressure injection molding, which can damage the LGA housing and lead to contamination and whisker formation issues, especially with lead-free soldering connections.
Innovation Solution
A method involving a carrier element with a microcomponent receptacle for injection molding a housing around the microcomponent without soldering, using a filler material like silicone to secure the microcomponent under low pressure, allowing for stress-free assembly and avoiding contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure injection molding is used to produce the housing, then the housing can be manufactured efficiently, but the microcomponent and LGA housing are damaged
Solution Approach 1:
The manufacturing process is divided into distinct stages: first producing the housing without the microcomponent, then separately mounting the microcomponent onto the LGA housing, and finally encapsulating with filler material. This segmentation allows the housing to be molded under high pressure without exposing the microcomponent to damaging conditions.
Solution Approach 2:
The housing is produced in advance through injection molding before the microcomponent is mounted. This preliminary action enables the housing structure to be ready and robust before the sensitive microcomponent is introduced, avoiding exposure to high pressure and temperature during the molding process.
2Adaptability or versatility
If lead-free soldering connections are used, then RoHS regulations are met, but whisker formation and flux contamination occur
Solution Approach 1:
The soldering process and associated harmful elements (flux, solder material) are completely removed from the connection method. Instead of soldering, the patent uses direct mechanical contact between the LGA housing contact elements and the carrier strip, eliminating the source of whisker formation and flux contamination.
Solution Approach 2:
The patent employs a simple, disposable-like approach where the mechanical contact connection is used without requiring durable solder joints. The focus shifts to reliable mechanical contact during the encapsulation process rather than permanent metallurgical bonds.
3Reliability
If the LGA housing is extrusion-coated with silicone before injection molding, then the LGA housing is protected, but silicone displacement and penetration into contact locations occur
Solution Approach 1:
The LGA housing is produced and prepared in advance before the filler material encapsulation step. The mounting of the microcomponent onto the LGA housing occurs after housing production but before final encapsulation, ensuring that contact locations are established prior to any filler material introduction.
Solution Approach 2:
The problematic intermediate extrusion-coating step with silicone is removed from the process sequence. Instead of coating the LGA housing with silicone before injection molding, the patent directly mounts the microcomponent onto the bare LGA housing, then encapsulates the entire assembly with filler material in a controlled manner that prevents contact location contamination.
4Volume of moving object
If miniaturized LGA circuits are used, then component size is reduced, but second-level packaging becomes extremely challenging
Solution Approach 1:
The LGA housing, microcomponent, and filler material are combined into a single integrated encapsulated unit. The mounting process merges the microcomponent attachment with the final encapsulation step, creating a unified structure that simplifies the overall packaging complexity despite the miniaturized scale.
Solution Approach 2:
The carrier strip acts as an intermediary element between the microcomponent and the LGA housing contact elements. This mediator facilitates the connection process, enabling precise and reliable mounting of the miniaturized microcomponent onto the LGA housing without requiring complex direct bonding procedures.
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 method enables cost-effective, lead-free connections, reduces stress on microcomponents, and allows for variable production of electronic components, accommodating different sizes and applications, while maintaining accurate positioning and minimizing setpoint errors.
Implementation Method 1
injection molding a housing around the carrier element
Implementation Method 2
The filler material advantageously takes on several functions, such as protecting the microcomponents from environmental influences, mechanical fixing and fastening the microcomponent in the housing, as well as damping the microcomponent.
Data Source
AI summary
A method for producing an electronic component includes: providing at least one carrier element having a microcomponent receptacle configured for contacting at least one microcomponent, injection molding a housing around the carrier element, the microcomponent receptacle being situated in a cavity of the housing that is open on at least one side, introducing the microcomponent into the microcomponent receptacle in the cavity to contact the microcomponent to the carrier element, and injecting the cavity using a filler material to fix the microcomponent in the housing and in the microcomponent receptacle.