Inkjet-Printed Test Pins for Pin-Efficient Semiconductor Packages
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Solution Overview
Problem
In semiconductor fabrication, a significant portion of pins are dedicated for testing purposes, leading to waste as these test pins are not used after testing, especially in packages with limited pin counts, resulting in inefficient use of available pins.
Innovation Solution
Inkjet printing of test pins between normal contacts on a substrate, which are lower in height and shape to fit between existing pins, allowing for all pins to be used for functionality and enabling testing without reserving pins for test purposes, using a conductive paste and a laser flash lamp for curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a portion of contacts is dedicated to test pins for sensing purposes, then testing capability is improved, but pin count efficiency deteriorates as these pins are wasted and not used in final products
Solution Approach 1:
The patent segments the pin structure into two distinct types: functional pins for product operation and test pins for sensing. Test pins are specifically designated with lower height and positioned between functional pins, allowing simultaneous presence of both pin types without interfering with each other's function. This segmentation enables testing capability while preserving functional pin count efficiency.
Solution Approach 2:
The patent introduces height as an additional dimension to differentiate between functional pins and test pins. Test pins are formed with lower height compared to full-height functional pins, creating a vertical distinction that allows both pin types to coexist on the same substrate without conflict. This dimensional differentiation resolves the contradiction by enabling testing functionality without sacrificing functional pin availability.
2Device complexity
If test pins are formed with lower height to fit between existing pins, then pin integration is improved, but manufacturing complexity increases due to additional formation steps
Solution Approach 1:
The patent merges the formation of test pins with the existing pin formation process by using the same inkjet printing technology and conductive paste materials. Both functional pins and test pins are created through similar manufacturing steps, reducing the need for entirely separate process equipment and methodologies. This merging approach mitigates the increase in manufacturing complexity despite the additional integration requirements.
Solution Approach 2:
The patent utilizes parameter changes in the inkjet printing process to create different pin heights. By adjusting printing parameters such as paste volume, number of print passes, or curing conditions, the same inkjet equipment can produce both full-height functional pins and lower-height test pins. This parameter-based differentiation simplifies manufacturing by using a single process platform for both pin types.
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 allows all pins to be utilized for functional purposes, reducing the form factor and enabling additional functions, as test pins are only printed for testing and covered during manufacturing, ensuring none are reserved for testing in final products.
Implementation Method 1
using a conductive paste and a laser flash lamp for curing
Data Source
AI summary
In an aspect, an apparatus includes a package. The package includes a substrate, a plurality of components located on a top surface of the substrate, a plurality of ball pads located on a bottom surface of the substrate, a plurality of balls, and a plurality of test pads located on the bottom surface of the substrate. Individual balls of the plurality of balls are attached to individual ball pads of the plurality of ball pads.