Probe Card Space Transformer Rigidity via Composite Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional probe cards face issues with warp caused by elastic force from the interposer, leading to instability in contact resistance with semiconductor wafers, especially for larger diameter wafers, and increasing manufacturing time and cost to enhance mechanical rigidity.
Innovation Solution
A probe card design that includes a flat wiring board, an interposer, a space transformer, and a probe head, where the interposer and space transformer are bonded using adhesive and/or screws, with post members for additional support, and coil spring connection terminals to improve rigidity and flatness without increasing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the space transformer is increased to improve mechanical rigidity, then the rigidity is improved, but the manufacturing time increases and cost increases
Solution Approach 1:
The patent applies composite materials by bonding a metal plate to the back surface of the space transformer base material. This combination of metal (providing rigidity) and ceramic/base material (providing electrical insulation and structural integrity) achieves the required mechanical rigidity without increasing the thickness of the space transformer itself, thereby avoiding additional manufacturing steps and cost associated with making the base material thicker or adding dummy wiring layers.
2Strength
If the number of wiring layers is increased to improve mechanical rigidity, then the rigidity is improved, but the manufacturing time increases and cost increases
Solution Approach 1:
Instead of adding dummy wiring layers to the space transformer, the patent uses a composite structure with a metal plate bonded to the back surface. This approach achieves rigidity enhancement without complicating the wiring layer structure, maintaining electrical performance while providing the necessary mechanical strength.
Solution Approach 2:
The metal plate acts as an intermediary element bonded to the back surface of the space transformer. This intermediary component provides the required mechanical rigidity and structural support without interfering with the existing wiring layers or requiring additional wiring complexity within the space transformer itself.
3Area of stationary object
If the probe card surface area is increased to accommodate more probes for larger wafers, then the number of probes increases, but the warp increases due to elastic force from interposer
Solution Approach 1:
The patent employs composite materials by bonding a metal plate to the back surface of the space transformer. This composite structure enhances the overall rigidity and reduces warp caused by elastic forces from the interposer, enabling the probe card to maintain flatness across larger surface areas required for accommodating more probes on 12-inch wafers.
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 enhances the rigidity of the space transformer at a low cost, maintaining probe card flatness and accuracy, reducing manufacturing time, and ensuring stable contact resistance across the semiconductor wafer.
Implementation Method 1
the interposer and space transformer are bonded using adhesive and/or screws
Data Source
AI summary
A probe card includes a flat wiring board having a wiring pattern corresponding to a circuit structure for generating a signal for a test, an interposer that is stacked on the wiring board and relays wirings of the wiring board, a space transformer that is stacked on the interposer and fastened thereto by an adhesive, transforms a space between the wirings relayed by the interposer, and leads the wirings out to a surface opposite a surface facing the interposer, and a probe head that is stacked on the space transformer and houses and holds a plurality of probes.