Vertical Probe Pin Structure for Narrow-Pitch Buckling Control

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Solution Overview

Problem

Existing vertical probe cards face issues such as probe pin buckling, excessive pressure leading to abrasion and foreign substance generation, and increased fatigue failure due to high pressing forces required for electrical testing, especially with narrower pitch arrangements, which cause short-circuits and reduced rigidity in guide plates.

Innovation Solution

A vertical probe card design featuring probe pins with a first and second plunger, an elastic portion with uniform thickness, and a support portion to prevent buckling, allowing for a wiping operation and maintaining vertical state during overdrive, with a pitch range of 50 μm to 160 μm and lateral width of 40 μm to 200 μm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high pressing force is applied to provide sufficient overdrive for probe pins, then good electrical and mechanical contact is ensured, but excessive pressure causes abrasion of guide hole inner walls and fatigue failure of probe pins

Engineering Contradiction:

Improveelectrical and mechanical contact qualityVSAvoidprobe pin durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The probe pin is divided into functionally distinct segments: a plunger portion for contact, an elastic portion for compliance, and a support portion for structural integrity. This segmentation allows each part to optimize its function - the elastic portion absorbs pressure variations without transmitting excessive force to the guide holes, while the support portion maintains strength to prevent fatigue failure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The probe pin structure transitions from a uniform design to a variable cross-sectional design. The elastic portion has a smaller cross-section than the support portion, allowing it to deform elastically under pressure while the larger support portion resists buckling and fatigue. This parameter change enables the pin to accommodate pressure variations without excessive force transmission.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If probe pins are arranged at narrower pitch to cope with integration trends, then testing capability for modern semiconductor devices is improved, but adjacent probe pins contact each other causing short-circuits when buckled

Engineering Contradiction:

Improvetesting capability for narrow pitch devicesVSAvoidelectrical isolation between adjacent pins

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Instead of allowing the probe pin body to buckle horizontally (conventional approach), the invention inverts the compliance mechanism by restricting horizontal deformation through the support portion and allowing only vertical elastic compression. This reversal prevents adjacent pins from contacting each other while maintaining electrical compliance with the test substrate.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The probe pin exhibits asymmetric deformation characteristics: the support portion with larger cross-section resists horizontal buckling to prevent pin-to-pin contact, while the elastic portion with smaller cross-section allows vertical compression for electrical compliance. This asymmetric design enables narrow pitch arrangements without short-circuits.

Inventive Principle:

Principle #4Asymmetry

3Productivity

If guide holes are arranged at narrower pitch to accommodate probe pins, then testing of narrow pitch devices is enabled, but clearance width between guide holes is reduced making processing difficult and guide plate rigidity decreased

Engineering Contradiction:

Improvecapability to test narrow pitch devicesVSAvoidguide hole processing difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The probe pin is segmented into a support portion with larger cross-section for structural integrity and an elastic portion with smaller cross-section for compliance. This segmentation allows the pin to maintain sufficient rigidity for handling and insertion while the elastic portion provides the necessary flexibility, reducing the need for excessively large guide hole clearances.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

By varying the cross-sectional parameters along the probe pin length (larger at support portion, smaller at elastic portion), the design optimizes the balance between rigidity and flexibility. This enables narrower guide hole pitch while maintaining manufacturability and guide plate rigidity.

Inventive Principle:

Principle #35Parameter changes

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

The design effectively tests electrical characteristics without probe pin bending, reduces abrasion and foreign substance generation, and enhances probe card durability, enabling stable electrical connections and extended lifespan.

Implementation Method 1

an elastic portion (130) configured to elastically displace the first plunger (110) and the second plunger (120) in a length direction of the probe pin (100)

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12618870B2Vertical probe card

Publication Date: 2026.05.05 POINT ENG

AI summary

Proposed is a vertical probe card capable of effectively testing the electrical characteristics of a test object without a body thereof being elastically bent or curved in a convex shape in the horizontal direction by pressure applied to opposite ends thereof.