Conductive Inspection Probe with Protruded Particles for Stress Relief
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Solution Overview
Problem
Conduction inspection devices, such as probe cards, face issues with cracks and voids forming in conductive materials due to compressive stress, leading to impaired conductivity and repeated test failures when used for BGA substrates.
Innovation Solution
The use of conductive particles with a specific structure, comprising a substrate particle and a conductive layer with multiple protrusions on its surface, which helps in relieving compressive stress and preventing the formation of cracks and voids, ensuring consistent conduction performance even after repeated tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive material is used in through holes, then initial conduction performance is achieved, but cracks and voids form under compressive stress leading to conductivity impairment
Solution Approach 1:
The patent changes the physical and chemical parameters of the conductive material by incorporating particles with specific properties: compressive elasticity modulus of 100-1000 GPa, hardness of 3-8 GPa, and controlled particle size distribution (0.1-10 μm). These parameter changes enable the material to withstand compressive stress while maintaining conduction performance.
Solution Approach 2:
The patent creates a composite conductive material consisting of multiple components: conductive particles (metal or metal oxide), binder resin, and optional filler particles. This composite structure combines the electrical conductivity of metal particles with the mechanical strength and stress absorption capabilities of the binder and filler, resolving the contradiction between conduction performance and compressive stress resistance.
2Productivity
If repeated compression tests are performed, then conduction testing function is maintained, but voids accumulate in conductive material causing test failure
Solution Approach 1:
The patent introduces dynamic characteristics to the conductive material through the binder resin component, which has elongation at break of 50-500%. This allows the material to dynamically absorb and dissipate compressive energy through elastic deformation during repeated tests, preventing permanent damage and void formation while maintaining continuous conduction performance.
Solution Approach 2:
The patent optimizes the binder resin content to 1-50 wt% of the total conductive material, creating a balanced composition that provides sufficient binding strength to hold conductive particles together while allowing enough flexibility to accommodate repeated compression cycles without void formation.
3Ease of operation
If hard sharp-tipped probes are used, then contact with electrode pads is achieved, but electrode damage occurs
Solution Approach 1:
The patent changes the mechanical parameters of the probe tip material by selecting conductive particles with controlled hardness (3-8 GPa) and compressive elasticity modulus (100-1000 GPa). This creates a tip that is hard enough to maintain contact with electrode pads but not so hard as to cause damage, achieving ease of operation without harmful effects.
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 solution enhances the durability and accuracy of conduction inspections by maintaining conductivity and preventing contact marks on tested components, thereby improving the reliability of the conduction inspection device.
Implementation Method 1
the conductive particles each comprising a substrate particle and a conductive layer on the surface of the substrate particle, and the conductive layer having multiple protrusions on the outer surface thereof
Data Source
AI summary
Provided is a conduction inspection device member, wherein cracks and voids are less likely to form in conductive parts, conduction performance is less likely to be impaired even when a conduction test is repeated, and contact marks are less likely to remain in the portion of the member in contact with a member to be tested. Also provided is a conduction inspection device comprising the conduction inspection device member. The conduction inspection device member comprises a substrate 13, through holes 11, and conductive parts 12. The multiple through holes 11 are arranged in the substrate 13, the conductive parts 12 are housed inside the through holes 11, and the conductive parts 12 contain conductive particles 2. The conductive particles 2 each comprise a substrate particle 21 and a conductive layer 22 on the surface of the substrate particle 21. The conductive layer 22 has multiple protrusions 23 on the outer surface thereof.