Collapsible Probe Tower for High-Density Semiconductor Testing
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Solution Overview
Problem
The high density of contact towers on semiconductor devices limits access to probe towers during testing, leading to potential damage or electrical shorts due to the close proximity of test probes with adjacent contact bumps.
Innovation Solution
A collapsible probe tower is formed with a probe bump that exceeds the height of contact bumps for testing, which can then be reduced in height through a reflow process to prevent interference during device mounting, allowing for increased contact density and preventing electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If contact towers are arranged at high density on semiconductor devices, then productivity and device integration are improved, but access to probe towers during testing becomes difficult and risk of electrical shorts increases
Solution Approach 1:
The probe tower structure is made dynamic through the collapsible probe bump that can transition between an extended testing configuration and a collapsed mounting configuration. This allows the same structure to provide both testing access and high-density contact arrangement without conflict
Solution Approach 2:
The solution introduces a vertical dimension to the problem by extending the probe bump height above the contact tower tops during testing, creating vertical clearance that eliminates the need for lateral spacing between probe and contact towers
2Productivity
If probe towers are positioned close to contact towers to increase contact density, then productivity is improved, but the risk of electrical shorts and damage to contact bumps increases
Solution Approach 1:
The probe bump dynamically changes height based on operational phase: extended during testing to prevent shorts, collapsed during mounting to enable high density. This temporal separation of states resolves the contradiction between proximity and safety
Solution Approach 2:
The probe bump height parameter is changed between two states: a first height (extended) during testing that prevents electrical shorts, and a second height (collapsed) during mounting that enables high contact density
3Manufacturing precision
If a rigid test probe structure is used to contact test points, then manufacturing precision is improved, but the risk of damaging fine-pitch solder micro-bumps increases
Solution Approach 1:
The probe tower structure incorporates a collapsible probe bump that can dynamically adjust its mechanical properties - rigid when extended for precise testing, compliant when collapsed to avoid damage during mounting operations
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 collapsible probe tower design enables safe testing without damaging adjacent contact bumps and allows for higher contact density on semiconductor devices by reducing the clearance space between probe pads and contact bumps, preventing electrical shorts and facilitating efficient device mounting.
Implementation Method 1
heating the conductive material that forms the contact bump and the probe bump to provide a reflow
Data Source
AI summary
A collapsible probe tower device and methods of forming thereof, are disclosed. In one example embodiment, a method of forming a device includes providing a semiconductor die substrate having a contact pad and a probe pad, wherein the contact pad and probe pad are adhered to the substrate, forming a contact bump by applying a conductive material to a contact structure surface of a contact tower, wherein the contact tower includes the contact pad, forming a probe bump by applying a conductive material to a probe structure surface of a probe tower, wherein the probe tower includes the probe pad, and heating the conductive material that forms the contact bump and the probe bump to provide a first reflow, wherein after the first reflow, the height of a top surface of the probe bump exceeds the height of a top surface of the contact bump.