Fine-Pitch Probe Card With Spring-Pin Interposer and RDL
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Solution Overview
Problem
Current probe card designs are inadequate for fine-pitch circuit probe testing of semiconductor IC devices due to limitations in pin spacing, substrate durability, and electrical performance, leading to increased costs and reduced effectiveness in testing emerging technologies with higher integration densities.
Innovation Solution
A probe card design featuring an interposer structure with spring pins and a redistribution layer that allows for reduced pin spacing and improved elastic deformability, enabling fine-pitch testing with enhanced alignment and impedance control, and allowing for easy replacement of damaged components without thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional probe card designs are used, then manufacturing simplicity is maintained, but pin spacing cannot be reduced sufficiently for fine-pitch testing
Solution Approach 1:
The probe card is divided into a substrate and an overmold portion that are formed separately and then integrated. The overmold portion contains the probe pins and is molded over the substrate, allowing independent optimization of each component's manufacturing process while achieving fine pin spacing in the final integrated structure.
Solution Approach 2:
The probe pins are arranged in a three-dimensional configuration where the overmold portion extends vertically from the substrate surface. This vertical dimensionality allows probe pins to be positioned at precise locations with fine spacing without compromising the underlying substrate structure or manufacturing feasibility.
2Reliability
If probe pins are made more durable, then resistance to damage improves, but ease of replacement deteriorates
Solution Approach 1:
Each probe pin is segmented into a pin body and a pin head, with the pin head forming an integral part of the overmold portion. This segmentation allows the pin body to be replaced independently while leaving the pin head and overmold structure intact, combining durability with ease of repair.
Solution Approach 2:
The design enables selective replacement of damaged probe pin bodies while recovering and reusing the pin heads that remain embedded in the overmold portion. This reduces waste and lowers repair costs by retaining functional components.
3Quantity of substance
If high integration density is achieved, then component count increases, but testing effectiveness decreases due to inadequate pin spacing
Solution Approach 1:
The mold material's viscosity and curing characteristics are optimized to enable precise positioning of probe pins at very close spacings. By controlling the molding parameters and material properties, fine pin spacing is achieved without compromising pin alignment or testing reliability.
Solution Approach 2:
The probe card uses a composite structure combining a substrate material with an overmold material that has different mechanical and electrical properties. This composite construction allows the overmold portion to provide precise pin positioning and fine spacing while the substrate provides structural support and electrical connectivity.
4Ease of repair
If thermal processing is used for repair, then component replacement is possible, but substrate damage occurs
Solution Approach 1:
The repair process is segmented into mechanical removal of pin bodies without thermal processing. Since the pin heads remain embedded in the overmold portion, replacement can be accomplished through simple mechanical operations that do not subject the temperature-sensitive substrate to harmful thermal exposure.
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
Enables accurate and cost-effective fine-pitch circuit probe testing of semiconductor devices with improved alignment and reduced impedance mismatch, while facilitating easy repair and replacement of damaged components.
Implementation Method 1
improved elastic deformability
Data Source
AI summary
A probe card for use in circuit probe testing and methods of fabrication thereof. The probe card includes a circuit board, an interposer structure that is mounted to the circuit board, and a probe structure mounted to the interposer structure and including a probe substrate, a redistribution layer over the probe substrate, and a plurality of probe pins over the redistribution layer. The interposer structure may include a plurality of elastically-deformable interposer pins electrically connecting the circuit board to the probe substrate. The center-to-center spacing (i.e., pin pitch) between the interposer pins may be greater than the center-to-center spacing (i.e., a second pin pitch) between the probe pins. A probe card in accordance with various embodiments may enable circuit probe testing of a device-under-test with a pitch between adjacent probe pins that is less than 50 μm.