Probe Card Anchor Pads for Flexible Board Adhesion
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Solution Overview
Problem
The flexible wiring board in probe cards can detach from the substrate due to insufficient adhesive strength, leading to reduced contact reliability and height inconsistencies among probes, and thermal expansion of adhesive bubbles compromises flatness.
Innovation Solution
The probe card design includes anchor pads on the adhesive surface of the flexible wiring board, aligned with electrode pads, to increase adhesive surface area and control adhesive thickness, minimizing height variations and preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flexible wiring board is adhered to the substrate using adhesive, then the probe card can be assembled, but the flexible wiring board may detach from the substrate due to insufficient adhesive strength
Solution Approach 1:
The adhesive surface is segmented into multiple anchor pads distributed across the flexible wiring board. This segmentation increases the total adhesive contact area and distributes the adhesive strength requirement across multiple localized bonding points, preventing detachment while maintaining ease of assembly.
Solution Approach 2:
The anchor pads extend in the thickness dimension (protruding from the flexible wiring board surface), creating a three-dimensional adhesive interface. This dimensional change increases the effective adhesive surface area beyond what would be achieved with a flat adhesive layer, significantly improving bond strength.
2Ease of manufacture
If adhesive is applied to attach the flexible wiring board, then the probe card can be assembled, but variations in adhesive thickness cause height inconsistencies among probes
Solution Approach 1:
The adhesive is segmented into discrete portions under each anchor pad rather than a continuous layer. This segmentation allows uniform thickness control at each localized bonding point while maintaining ease of assembly, preventing height variations among probes.
Solution Approach 2:
Each anchor pad creates a localized adhesive region with controlled thickness and properties. The local quality of the adhesive layer is optimized at each anchor pad location, ensuring consistent probe heights while simplifying the overall assembly process.
3Ease of manufacture
If adhesive is used to adhere the flexible wiring board, then the probe card can be assembled, but bubbles in the adhesive expand during high-temperature testing and contract during low-temperature testing, reducing flatness
Solution Approach 1:
The adhesive is divided into small, isolated portions under each anchor pad. This segmentation limits the volume of adhesive that can form bubbles, and the distributed nature of the adhesive portions allows for better stress distribution and reduced bubble expansion effects during temperature cycling, maintaining flatness while preserving ease of assembly.
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 design enhances the secure adhesion of the flexible wiring board to the substrate, maintains probe height consistency, and improves contact reliability by reducing adhesive bubble expansion and flatness issues.
Implementation Method 1
a flexible wiring board made of an insulating film and having an adhesive surface adhered to the substrate via an adhesive
Implementation Method 2
the first anchor pads are protrusions provided on the adhesive surface of the flexible wiring board, and the spaces between adjacent first anchor pads form recesses. As a result, alternating protrusions and recesses are formed on the adhesive surface of the flexible wiring board, increasing the surface area
Implementation Method 3
excess adhesive on the first anchor pads is accommodated in the recesses, which helps control the thickness of the adhesive layer between the first anchor pads and the substrate
Implementation Method 4
The inspection of the semiconductor device is conducted by bringing the semiconductor wafer close to the probe card, allowing the tips of the probes to contact the electrodes on the wafer, and establishing electrical continuity
Data Source
AI summary
[Problem] To prevent a flexible wiring board from peeling off from a substrate.[Solution] This probe card comprises: a substrate 30 having a flat surface that faces an object 20 to be tested; a flexible wiring board 50 which is composed of an insulating film 51 and has an adhesive surface adhered to the substrate 30 via an adhesive agent 40 and a probe mounting surface on which two or more electrode pads 520 are aligned and arranged at a predetermined interval; and two or more probes 70 respectively disposed on the electrode pads 520. Two or more first anchor pads 521 are respectively formed at positions on the adhesive surface that correspond to the electrode pads 70.