Ceramic Wiring Substrate for Probe Card Thermal Matching
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Solution Overview
Problem
Conventional probe cards face challenges due to the mismatch in thermal expansion coefficients between semiconductor wafers and wiring substrates, leading to misalignment and increased manufacturing costs, especially when requiring fine pitch wiring and high-temperature testing.
Innovation Solution
A wiring substrate with a ceramic substrate having a coefficient of thermal expansion close to that of silicone, combined with thin-film wiring sheets and zero insertion force connectors, eliminates the need for a space transformer, allowing for fine pitch wiring and improved thermal matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wiring substrate with fine pitch wiring is used, then wiring precision is improved, but manufacturing complexity increases due to the need for space transformers and multiple layers
Solution Approach 1:
The patent changes the material parameter of the wiring substrate from conventional resin-based materials to ceramic materials, enabling fine pitch wiring (100 μm or less) to be achieved directly on the substrate without requiring complex space transformers or multiple stacked layers. This material parameter change fundamentally resolves the contradiction between wiring precision and structural complexity.
2Stability of the object's composition
If the coefficient of thermal expansion of the wiring substrate is increased to match semiconductor wafer, then thermal compatibility is improved, but material selection becomes more restricted
Solution Approach 1:
The patent employs ceramic materials as the wiring substrate, which inherently possess coefficient of thermal expansion values (3.0×10−6 to 5.0×10−6/° C.) that closely match semiconductor wafers. This composite material approach provides both thermal compatibility and manufacturing feasibility, resolving the contradiction between thermal stability and ease of manufacture.
3Ease of manufacture
If conventional resin-based wiring substrate is used, then ease of manufacture is maintained, but misalignment occurs between probe tips and electrodes under temperature variation
Solution Approach 1:
The patent changes the thermal expansion parameter of the wiring substrate by using ceramic materials instead of resin-based materials. This parameter change ensures that the substrate maintains dimensional stability under temperature variation (25 to 125° C.), preventing misalignment between probe tips and electrodes while maintaining manufacturing feasibility.
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 configuration enables precise and cost-effective high-frequency signal transmission, reduces manufacturing complexity, and prevents misalignment, resulting in improved durability and reduced costs.
Implementation Method 1
the coefficient of thermal expansion (3.4×10−6/° C.) of a semiconductor wafer composed mostly of silicone is significantly smaller than the coefficient of thermal expansion (12×10−6 to 17×10−6/° C.) of a wiring substrate composed mostly of resin such as glass epoxy or polyimide
Data Source
AI summary
A wiring substrate that allows wiring at a fine pitch and has a coefficient of thermal expansion close to the coefficient of thermal expansion of silicone, and a probe card that includes the wiring substrate are provided. To this end, there are provided a wiring substrate that includes a ceramic substrate having a coefficient of thermal expansion of 3×10−6 to 5×10−6/° C. and one or more thin-film wiring sheets stacked on one surface of the ceramic substrate, and a probe head on which a plurality of conductive proves are arranged in accordance with wiring on the thin-film wiring sheet, which holds individual probes while preventing the probes from coming off and allowing both ends of each probe to be exposed, and which is stacked on the wiring substrate while one end of each probe is brought into contact with the thin-film wiring sheet.