Straight Probe Semiconductor Bond Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bond testing systems for semiconductor assemblies, particularly those with solder balls or bumps, face challenges in measurement accuracy, speed, and usability due to the use of bent probe pins that introduce bending moments and friction, limiting force application and requiring manual handling and costly consumable test pins.
Innovation Solution
A system employing a straight, thermally conductive probe with a clamping mechanism and a thermally conductive ceramic heater, allowing for direct axial force application and reducing friction, enabling more accurate and efficient pull testing, as well as the ability to perform push and fatigue tests, with automated probe loading and reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bent probe pin is used to engage the hook and transfer force, then the test can be performed on solder balls, but measurement accuracy deteriorates due to bending moments and friction
Solution Approach 1:
The invention removes the bent probe pin and hook mechanism from the system. Instead, a straight probe pin directly engages the solder ball, eliminating the intermediate bent connection that caused measurement errors. The force is applied axially through the straight pin without bending moments or friction at engagement points.
Solution Approach 2:
Rather than using a bent pin to transfer force indirectly through a hook, the invention inverts the approach by using a straight pin that applies force directly to the solder ball. The engagement method is reversed from indirect (hook-to-bent-pin) to direct (straight-pin-to-ball).
2Force
If a bent probe pin is used, then force can be transferred to the bond, but the maximum applicable force is limited by the strength of the bend
Solution Approach 1:
The bent probe pin is removed entirely from the system. The straight probe pin eliminates the weak point at the bend, allowing maximum force to be applied to the solder ball without being limited by the strength of a bent connection.
3Loss of substance
If manual handling of test pins is required, then probe reuse can be implemented, but operational time increases and safety risks arise from operator interaction with hot components
Solution Approach 1:
The system performs automated probe handling including loading, heating, testing, and cooling. The probe is automatically retracted after testing while still hot, allowing rapid cooling and reuse without manual intervention. This eliminates safety risks and reduces operational time compared to manual handling.
Solution Approach 2:
The probe is designed for reuse rather than disposal. After automated testing, the probe is retracted and cooled, then ready for the next test cycle. This recovering approach reduces operational time and eliminates the need for manual handling of hot components.
4Temperature
If a large titanium block is used as heater support, then mechanical support is provided, but the system complexity and size increase
Solution Approach 1:
The large titanium heater block is removed from the system. Instead, a small susceptor element directly coupled to the probe tip provides the necessary heating function. This dramatically reduces system size and complexity while maintaining the required temperature capability.
Solution Approach 2:
Rather than using a large block to provide heat, the invention concentrates heating capability in a small localized susceptor element at the probe tip. This local quality approach provides sufficient heating support without the bulk of a large titanium block.
5Temperature
If cooling is performed by air jet, then the probe and solder can be cooled rapidly, but the operational time is extended
Solution Approach 1:
The probe is automatically retracted from the hot solder ball immediately after testing, allowing it to cool naturally without requiring extended air jet cooling. This self-cooling approach reduces operational time while achieving adequate cooling for probe reuse.
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
Improves measurement accuracy, increases the maximum applicable force, reduces operational time and costs by allowing probe reuse, and enhances safety through reduced operator interaction with hot components, while enabling automated testing and probe management.
Implementation Method 1
a heater for heating a tip of said probe to a temperature at or above a temperature at which the bond is melted
Implementation Method 2
the heater comprises a thermally conductive tube formed from a ceramic material which surrounds at least a part of said probe
Implementation Method 3
the bond is cooled and solidified to fix the probe tip in the bond
Data Source
Figure 1
Figure 2
Figure 3
AI summary
the invention comprises an apparatus for applying a pull test to a bond of a semi-conductor assembly, the bond comprising a ball or a bump of solder, the apparatus comprising: a probe, said probe comprising a straight, thermally conductive pin; a heater for heating a tip of said probe to a temperature at or above a temperature at which the bond is melted; a holder for supporting said probe, the holder comprising a clamping mechanism that is configured to provide a clamping force on the probe; an actuation device for moving up and down said holder and said probe supported in said holder; a means for applying a pull force on said holder which in turn applies a pull force to said probe; and a force measuring system for measuring a force applied to said probe during the pull test, wherein after said probe tip has been heated to a temperature at or above a temperature at which the bond is melted, said probe tip is brought into contact with the bond, the bond is melted by heating of the probe and the bond is cooled and solidified to fix the probe tip in the bond, the probe is then retracted by the pull force applying means to apply a pull force to the bond, which pull force is measured by said force measuring system.