Testing Head With Variable Clearance Probes

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Solution Overview

Problem

The existing testing heads for probe cards face difficulties in assembling and replacing probes due to limited clearance between probes and guide holes, especially at the lower plate, which complicates the insertion process and requires manual, costly, and time-consuming operations.

Innovation Solution

The introduction of a testing head design with variable section passage holes, facilitated by an additional sliding plate that modifies the insertion passage section, allowing for easier probe insertion and subsequent precision adjustment, enabling increased probe density and simplified maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the clearance between probe and guide hole is reduced to ensure exact positioning, then measurement precision is improved, but ease of operation deteriorates due to difficult insertion

Engineering Contradiction:
Improvepositioning precisionVSAvoidinsertion ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The passage hole is designed with variable clearance along the insertion path. The upper portion has larger clearance to facilitate easy insertion of the probe, while the lower portion has smaller clearance to ensure precise positioning. This dynamic variation in clearance resolves the contradiction between ease of insertion and positioning precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different sections of the passage hole have different clearance characteristics. The upper section provides generous clearance for easy probe insertion, while the lower section provides tight clearance for precise positioning. This local differentiation of quality allows the system to achieve both ease of operation and measurement precision in different spatial zones.

Inventive Principle:
Principle #3Local quality

2Productivity

If the number of probes per unit area is increased to perform tests on low pitch integrated circuits, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvetest capacityVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The insertion function is extracted from the guide hole structure and assigned to a separate additional plate. This additional plate with larger clearance holes facilitates easy probe insertion, while the original guide holes maintain their precise positioning function. This separation allows high probe density without increasing overall structural complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The passage hole function is segmented into two distinct components: the original guide hole in the guide plate for precise positioning, and the additional opening in the separate additional plate for easy insertion. This segmentation allows each component to optimize its specific function without compromising the other, enabling high probe density while maintaining simplicity.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If manual manipulation is used to insert probes into tightly fitted guide holes, then manufacturing precision is maintained, but loss of time increases

Engineering Contradiction:
Improveassembly precisionVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

An additional plate with larger clearance openings is introduced as an intermediary component during the assembly process. This intermediate structure allows probes to be easily inserted without manual manipulation, significantly reducing assembly time. After insertion, the additional plate can be removed, leaving the probe properly positioned in the guide hole with precise alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design enhances the ease of assembly and replacement of probes, reduces operational costs, and improves the precision of the assembled system by providing a wider clearance for easier insertion and adjustable precision post-assembly.

Implementation Method 1

each probe is axially mobile through the respective housing holes, but with some friction which, along with the inherent flexibility of the probes themselves, confers a certain overall ability to withstand compression to the testing head assembly

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The introduction of the flexible needle into the above guide holes of relatively small diameter, also in view of the need to lead this needle through two holes on plates spaced apart by a separation space, proves to be concretely difficult

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4261547A1Testing head with vertical probes for a probe card and corresponding method of assembly
Publication Date: 2023.10.18 MICROTEST SPA
  • EP4261547A1 patent drawingFigure 1
  • EP4261547A1 patent drawingFigure 2~2A
  • EP4261547A1 patent drawingFigure 3~3B

AI summary

The present disclosure relates to a testing head (1) with vertical probes for a probe card (4) comprising: - at least one pair of support and guide plates (20, 30) arranged parallel to each other in a prefixed spaced apart relation and provided with a plurality of guide and housing holes (15, 35); - a plurality of contact probes (14) housed and extended between corresponding holes (15, 35) of the guide plates (20, 30); as well as - at least one additional plate (23, 33) slidingly mounted next to one (20) or the other (30) of the guide plates (20, 30) and provided with one corresponding plurality of holes (45) of the guide plates (20, 30). The disclosure also relates to a method of assembly of said testing head (1)