Selective Etching for Probe Wire Tips in Microelectronic Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for preparing test probe wires are inefficient in removing unwanted materials from densely populated arrays with varying pitches, leading to premature wear and increased replacement costs, especially as connection pads on microelectronic devices shrink in pitch.
Innovation Solution
A method involving wire body encapsulation and selective chemical etching, where the wire tips are masked and treated with a viscoelastic material and encapsulation liquid to protect the wire bodies during etching, allowing for uniform removal of outer layers without damaging the core, enabling efficient processing of arrays with pitches as low as 90 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outer layers of composite probe wires are removed by traditional methods, then the core material is exposed for electrical contact, but the wire tips wear prematurely and require frequent replacement
Solution Approach 1:
The patent applies preliminary action by performing selective chemical etching of the outer layers before the probe wires are actually used for testing. This pre-treatment exposes the durable core material at the tips while the wires are still on the probe card, preventing premature wear during subsequent testing operations and extending the operational lifespan of the probe wires.
Solution Approach 2:
The patent replaces mechanical stripping or abrasion methods with chemical etching using selective chemical solutions. This substitution allows for precise, uniform removal of outer conductive layers without mechanical stress or damage to the core material, resulting in sharper, more durable wire tips that maintain electrical contact integrity over extended periods.
2Productivity
If probe wires are densely populated with varying pitches to test complex dies, then more pads can be tested, but traditional etching methods become inefficient and cannot uniformly remove outer layers
Solution Approach 1:
The patent creates a universal etching solution that works effectively across probe wires with varying pitches and densities. The chemical etching process can be applied uniformly to entire arrays of probe wires regardless of their spacing or configuration, enabling efficient processing of high-density probe cards used for testing complex dies with multiple pads.
Solution Approach 2:
The patent utilizes parameter changes in the chemical etching process, including controlling etchant concentration, temperature, and exposure time, to achieve uniform removal of outer layers across probe wires with varying pitches. By adjusting these parameters, the process remains effective whether dealing with sparse or densely populated wire arrays.
3Manufacturing precision
If outer layers are not uniformly removed, then the core material may not be properly exposed, but aggressive removal methods can damage the wire core or surrounding pads
Solution Approach 1:
The patent introduces a chemical etchant as an intermediary substance that selectively removes outer conductive layers without directly contacting or damaging the wire core. The etchant acts as a mediator that facilitates controlled material removal through chemical reactions, allowing precise exposure of the core material while preventing mechanical damage that would occur with aggressive physical removal methods.
Solution Approach 2:
The patent applies local quality by making the etching process selective to specific outer layer materials while leaving the wire core intact. The chemical etchants are chosen to react with and remove only the outer conductive coatings (such as copper or aluminum) while being inert to the durable core material (such as tungsten or molybdenum), achieving uniform exposure of the core without damage through material-specific chemical properties.
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 extends the lifespan of test probe wires by uniformly exposing the core material, reducing wear and replacement costs, while maintaining reliable electrical contact and preventing damage to the pads.
Implementation Method 1
etching the wires to remove the outer coating at the second end of the wires
Implementation Method 2
covering the wires with an encapsulation material
Data Source
AI summary
Etching for probe wire tip is described particularly well suited to microelectronic device test. In one example, wires of a probe head are covered with an encapsulation material, the wires being attached to a test probe head substrate, each of the wires having two ends, the first end being attached to the substrate and the second end being opposite the substrate, each wire having an outer coating around a core. The wires are etched to remove the outer coating at the second end of the wires. The encapsulation material is then removed.