Elastic Contact Bump Probe Card for High-Density Semiconductor Testing
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Solution Overview
Problem
The increasing density and reduced pitch of electrode pads on semiconductor chips make it difficult for probe needles to contact them accurately, leading to unreliable connections due to the aspect ratio between the pad size and the thickness of the passivation film.
Innovation Solution
A probe card design featuring a substrate with through holes containing elastic members and contact bumps, where the contact bumps are shaped to match the electrode pads and can adjust to accommodate variations in pad thickness, ensuring reliable contact and electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If probe needles are used to contact electrode pads, then electrical connection is achieved, but contact reliability deteriorates due to reduced pad pitch and increased aspect ratio
Solution Approach 1:
The contact projection is designed with elastic properties, allowing it to dynamically adapt its shape and position to accommodate variations in electrode pad geometry and passivation film thickness, transforming a static rigid structure into a dynamic compliant one that maintains reliable contact
Solution Approach 2:
The aspect ratio of the contact projection is specifically optimized to match the aspect ratio of the electrode pad, and the elastic modulus of the contact projection material is selected to provide appropriate compliance, thereby changing the physical parameters to achieve reliable contact under varying conditions
2Ease of manufacture
If contact projections are formed by resin molding with fixed shape, then manufacturing is simplified, but contact reliability deteriorates when pad aspect ratio varies
Solution Approach 1:
The elastic modulus and geometric parameters of the contact projection are specifically designed to provide compliance that accommodates variations in pad aspect ratio, maintaining contact reliability while preserving the simplicity of resin molding manufacturing
Solution Approach 2:
The contact projection is designed with flexible elastic properties, allowing it to deform and adapt to the actual electrode pad geometry, transforming a rigid molded structure into a compliant contact element that maintains reliability across varying pad configurations
3Productivity
If the number of electrode pads is increased to handle higher signal density, then device capability is improved, but contact accuracy deteriorates
Solution Approach 1:
The elastic contact projection dynamically adapts to the reduced pitch electrode pads, maintaining accurate contact despite the increased density, thereby enabling high signal processing capacity without sacrificing contact precision
Solution Approach 2:
The contact projection is designed with localized elastic properties and optimized geometry to achieve precise contact at each individual pad location, allowing accurate multi-point contact across high-density electrode arrays
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 probe card reliably connects to multiple electrode pads, accommodating shape changes and variations in pad thickness, enabling efficient and accurate testing of semiconductor chips with reduced testing time and improved contact precision.
Implementation Method 1
an elastic member formed in the through hole to extend to the first surface and having a first surface and a second surface opposite to the first surface, wherein the first surface of the elastic member is located on a side of the first surface of the substrate, and the second surface of the elastic member is located on an inside of the through hole
Data Source
AI summary
In one embodiment, a probe card is provided. The probe card includes: a substrate having a first surface and a second surface opposite to the first surface; a through hole formed through the substrate and extending between the first surface and the second surface; an elastic member formed in the through hole to extend to the first surface; a through electrode formed in through hole to extend to the second surface; a first trace on a surface of the elastic member to be electrically connected to the through electrode; and a contact bump on the elastic member via the first trace to be electrically connected to the first trace, wherein the contact bump is electrically connected to an electrode pad formed on a DUT (device under test) when an electrical testing is performed on the DUT using the probe card.