Convex Test Socket Preserving IC Device Shape
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Solution Overview
Problem
Conventional device testers deform IC devices due to undue pressure, especially on curved substrates, leading to uneven and flattened surfaces during testing, which can result in permanent deformation and affect subsequent assembly processes.
Innovation Solution
A thermal control unit with a test socket assembly that conforms to the profile of the IC device under test, using a pedestal assembly with a heat-conductive pedestal, temperature-control fluid circulation, and a controllable force distributor to maintain the device's original shape and apply balanced forces during testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional flat test tooling is used on curved IC devices, then testing can be performed, but undue pressure is exerted on the device causing deformation and flattening of the substrate surface
Solution Approach 1:
The patent applies curvature to the test socket and pedestal surfaces to match the curved profile of the IC device substrate. Instead of using flat surfaces, the test tooling incorporates convex or concave surfaces that conform to the natural curvature of the bonded die-substrate assembly, thereby eliminating undue pressure points and preventing substrate deformation during testing.
Solution Approach 2:
The patent changes the geometric parameters of the test tooling surfaces from flat to curved, matching the substrate profile. By adjusting the curvature radius and surface geometry of the test socket and pedestal to correspond to the IC device's curved profile, the system maintains uniform contact pressure and prevents localized stress concentrations that cause deformation.
2Reliability
If elevated pressure is applied during testing to ensure contact, then electrical connections are improved, but the device surface becomes flattened and uneven
Solution Approach 1:
The curved surfaces of the test socket and pedestal distribute the contact pressure uniformly across the substrate surface by matching its natural curvature. This eliminates stress concentrations that would otherwise cause localized flattening and unevenness, while still maintaining sufficient contact pressure for reliable electrical connections throughout the test area.
3Device complexity
If flat pedestal and pusher are used, then device testing is simplified, but uneven pressure is exerted on supported versus unsupported surfaces
Solution Approach 1:
The patent modifies the pedestal and pusher surfaces from flat to curved profiles that match the substrate geometry. This curvature adaptation ensures that pressure is distributed uniformly across the entire substrate surface, including both supported and previously unsupported areas, eliminating the uneven force distribution caused by flat tooling.
Solution Approach 2:
The curved test socket and pedestal design serves multiple functions: it maintains uniform pressure distribution across the substrate, preserves device shape, and ensures consistent electrical contact. This multi-functional approach replaces the need for separate flat tooling components while achieving superior performance across multiple parameters.
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 solution effectively preserves the original shape of IC devices during testing, minimizing deformation and ensuring proper assembly by distributing forces evenly across the device, thus preventing permanent damage and ensuring reliable electrical connections.
Implementation Method 1
a temperature-control fluid circulation block
Implementation Method 2
temperature-control fluid circulation
Implementation Method 3
a thermally-conductive heater having a fuse coupled to a heating element
Data Source
AI summary
A convex testing stack useful in association with a thermal control unit (TCU) that may be used to maintain a set point temperature for testing of a convex IC device under test (DUT) is configured to preserve the convex shape of the DUT.