In Die Stepping Sort for Tight Pitch Testing
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Solution Overview
Problem
Current technologies are unable to effectively test electrical connections with pitches less than 65 μm in microelectronic packages, limiting the ability to verify the integrity of tight pitch interconnects in multi-die interconnect bridges.
Innovation Solution
A system and method utilizing a test head with probes arranged in a pattern with pitches less than 65 μm, combined with a computing device to apply test signals and receive voltage responses, allowing for the testing of individual bumps within a die, including the use of a space transformer and guide plates to maintain probe alignment and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current testing technologies are used, then testing capability is maintained for existing pitches, but testing of tight pitch connections less than 65 μm is not possible
Solution Approach 1:
The patent changes the critical parameter of probe pitch from conventional sizes to less than 65 μm, enabling testing of tight pitch connections. This is achieved through specialized probe design and configuration that maintains electrical functionality at reduced pitch dimensions.
Solution Approach 2:
The patent introduces an intermediary testing system that bridges the gap between existing testing capabilities and the required tight pitch testing. This includes specialized probe cards, positioning systems, and test architectures that enable indirect testing of EMIB interconnects through the bridge structure itself.
2Manufacturing precision
If probe pitch is reduced to less than 65 μm, then testing of tight pitch connections becomes possible, but probe alignment and rigidity become more difficult to maintain
Solution Approach 1:
The patent segments the testing system into multiple functional components: probe tips with pitch less than 65 μm, guide plates for alignment, support structures for rigidity, and positioning mechanisms. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The patent employs composite structures in the probe design, combining materials with different properties to achieve both the required pitch precision and mechanical rigidity. This may include rigid support structures with flexible tip elements or multi-layer probe card constructions.
3Reliability
If individual bumps are tested, then connection integrity is verified, but testing time increases due to stepping through repeatable blocks
Solution Approach 1:
The patent utilizes the periodic, repeatable nature of the bump pattern to implement efficient testing. By testing one complete repeatable block and then stepping to test identical blocks, the system leverages the periodic structure to reduce overall testing time while maintaining comprehensive coverage.
Solution Approach 2:
The patent applies the test results from one repeatable block as a template or copy for evaluating subsequent identical blocks. Since the bump patterns are repeatable, testing one block provides a reference that can be used to quickly evaluate other blocks, reducing the need for complete independent testing of each block.
Data Source
AI summary
An apparatus for testing a die can comprise a first printed circuit board (PCB), a space transformer, and a plurality of probes. The first PCB can be configured to connect to a second PCB. The space transformer can be attached to the PCB. The space transformer can include a plurality of traces. Each of the plurality of probes can be connected to one of the plurality of traces.