Multi-Layered Pad Structure for Wear-Resistant Wafer Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The correlation wafer used for testing integrated circuits often wears out or becomes damaged after multiple testing cycles, making it difficult to distinguish between tester failures and wafer integrity issues, and replacing it increases labor and cost in the manufacturing process.
Innovation Solution
A chip design featuring conductive structures with a gold first metal layer, nickel second metal layer, and gold third metal layer, stacked along a specific direction, and a passivation layer with polyimide layers, providing enhanced durability and electrical conductivity to withstand probe card testing without premature wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a single-layer pad structure is used for wafer testing, then the manufacturing process is simple, but the pad wears out quickly after multiple testing cycles
Solution Approach 1:
The pad is constructed with a multi-layer composite structure consisting of a first metal layer (e.g., copper or aluminum), a second metal layer (e.g., nickel or rhodium), and a third metal layer (e.g., gold). Each layer provides different properties: the first layer provides electrical conductivity, the second layer provides hardness and wear resistance, and the third layer provides corrosion resistance and bonding capability. This composite structure enables the pad to withstand multiple testing cycles while maintaining structural integrity.
Solution Approach 2:
The invention transitions from a single-layer (2D) pad structure to a multi-layer stacked (3D) structure. By adding the vertical dimension with multiple metal layers, the pad gains enhanced durability and functionality without significantly increasing the horizontal footprint, thus resolving the contradiction between durability and structural complexity.
2Reliability
If a multi-layer conductive structure is implemented on the pad, then the durability and conductivity are enhanced, but the manufacturing complexity increases
Solution Approach 1:
The multi-layer metal structure is pre-formed on the wafer pad before the wafer undergoes testing. This preliminary preparation ensures that the durable, multi-layer structure is already in place, eliminating the need for complex assembly operations during the testing process and simplifying the overall manufacturing workflow.
Solution Approach 2:
The invention optimizes parameters such as the thickness of each metal layer, the material composition, and the stacking sequence to achieve the desired balance between durability and manufacturability. By carefully controlling these parameters, the pad achieves enhanced reliability while remaining compatible with standard semiconductor manufacturing processes.
3Measurement precision
If the correlation wafer is frequently replaced due to wear, then the testing accuracy is maintained, but the labor time and cost increase
Solution Approach 1:
The multi-layer pad structure is designed to be self-durable, with the second and third metal layers providing inherent wear and corrosion resistance. This self-protecting structure eliminates the need for frequent replacements to maintain testing accuracy, thereby reducing labor time and costs while preserving measurement precision.
Data Source
AI summary
A chip includes pads having first connecting surfaces, and conductive structures located on the first connecting surfaces. The conductive structures are disposed on the first connecting surfaces. Each of the conductive structures includes first metal layer, second metal layer, and third metal layer. The first metal layer connects one of the pads, and the second metal layer is disposed between the first metal layer and the third metal layer. On every pad, the first metal layer, the second metal layer, and the third metal layer are stacked along first direction on the first connecting surface of the pad, and the first direction is parallel to normal direction of the first connecting surface, and the first metal layer is made of material comprising gold, and the second metal layer is made of material comprising nickel. A wafer is also provided.