Wiring Substrate Studs with Truncated Conical Flanges
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Solution Overview
Problem
Existing wiring substrates for electronic component inspection apparatuses are prone to cracking near the peripheral edge of the stud flange when an external force is applied, leading to inaccurate inspections and potential substrate breakage.
Innovation Solution
The wiring substrate features studs with a truncated conical flange portion, where the outside surface slopes from the center to the peripheral edge, mitigating stress and preventing cracks, and is joined to the ceramic laminate using a brazing material layer to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large external force is applied to the stud along the axial direction, then the stud can securely hold the wiring substrate, but a shearing force acts between the flange and substrate causing cracks in the ceramic near the peripheral edge
Solution Approach 1:
The flange is designed with non-uniform thickness, having a thicker center portion and a thinner peripheral edge portion. This local quality variation allows the center to withstand compressive loads while the thinner peripheral edge reduces stress concentration and prevents crack initiation in the adjacent ceramic substrate.
Solution Approach 2:
The flange thickness parameter is changed from uniform to non-uniform distribution. The center portion maintains sufficient thickness for load bearing, while the peripheral edge thickness is reduced to minimize the lever arm effect and shearing force transmitted to the ceramic substrate, thereby preventing cracks.
2Reliability
If the flange thickness is increased to prevent cracks, then crack resistance improves, but the stud becomes more susceptible to bending and the brazing material layer may become insufficient
Solution Approach 1:
The flange employs local quality variation with different thickness zones: the center portion is thicker to prevent bending and provide structural stability, while the peripheral edge is thinner to reduce stress on the ceramic substrate. This localized differentiation resolves the contradiction between overall strength and crack resistance.
Solution Approach 2:
The flange thickness is varied in the radial dimension, creating a gradient structure from center to periphery. This dimensional variation allows the flange to simultaneously provide bending resistance at the center and crack prevention at the edges, effectively resolving the contradiction through spatial differentiation.
3Area of stationary object
If the distance between via conductor and flange peripheral edge is reduced, then space utilization improves, but the substrate becomes more susceptible to cracking under external force
Solution Approach 1:
The flange's non-uniform thickness creates a local quality gradient that reduces stress concentration at the peripheral edge. This allows via conductors to be positioned closer to the flange edge without increasing crack risk, as the thinner peripheral region transmits less shearing force to the substrate, enabling better space utilization.
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 effectively prevents cracks in the ceramic laminate, ensures accurate electronic component inspection, and allows for precise positioning of probe pins at a fine pitch, enhancing the reliability and accuracy of the inspection process.
Implementation Method 1
the flange portion is joined to a metal layer formed on the back surface via a brazing material layer
Data Source
AI summary
A wiring substrate for electronic component inspection apparatus includes a first laminate which is formed by stacking a plurality of ceramic layers and which has a front surface and a back surface, and a plurality of studs joined to the back surface of the first laminate Each of the studs is composed of a flange portion which is circular in bottom view, and a bolt portion which perpendicularly extends from a center portion of an outside surface of the flange portion. The flange portion has a truncated conical shape and the outside surface from which the bolt portion protrudes, such that the outside surface slopes from the proximal end side of the bolt portion toward the peripheral edge of the flange portion and gradually approaches the inside surface of the flange portion.