Single Probe Test Device Using Scribe Line Short-Circuit Elements
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Solution Overview
Problem
As semiconductor processes advance, the increasing density of pads on chips complicates test device design, leading to higher costs, reduced reliability, and shorter lifetimes due to the need for more probes with closer pitch.
Innovation Solution
A test device and method that form short-circuit elements in scribe lines to connect multiple pads, allowing a single probe to test multiple pads by utilizing built-in switches on the chip to isolate non-testing pads, thereby reducing the number of probes required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of probes is increased to match the number of pads, then all pads can be tested, but the probe pitch becomes too close leading to higher cost, worse reliability, and shorter lifetime
Solution Approach 1:
Multiple pads are electrically connected through short-circuit elements formed in the scribe line, allowing a single probe to test multiple pads simultaneously. This merging of pad functions reduces the number of probes needed from N to 1, eliminating the probe density and reliability issues
Solution Approach 2:
A single probe is designed to perform multiple testing functions by sequentially connecting to different pad groups. The probe card becomes a multi-functional device that can test various pad combinations through the short-circuit element configurations, reducing overall device complexity
2Productivity
If the pad size is reduced and pads are distributed denser, then more chips can be manufactured per wafer, but the test device becomes more complicated with higher productive effort
Solution Approach 1:
The short-circuit elements connect multiple densely distributed pads into testable groups, allowing the test device to handle high-density pad layouts without requiring proportionally more probes. This enables maintaining high chip yield rates while managing test device complexity
Solution Approach 2:
The solution moves the complexity from the spatial dimension (probe density) to the temporal dimension (sequential testing through switching). Instead of increasing probe density in space, the system uses time-multiplexed testing where a single probe sequentially tests different pad groups controlled by switches
Data Source
AI summary
A test device uses a single probe to test plurality of pads of at least one chip, and includes a test circuit, a plurality of short-circuit elements and a plurality of probes. The plurality of short-circuit elements is formed in scribe lines around the at least one chip, where each of the plurality of short-circuit elements connects the plurality of pads, and the plurality of pads includes one testing pad and at least one non-testing pad. The plurality of probes receives a plurality of test signals generated by the at least one chip from the testing pad via the plurality of short-circuit elements, so the test circuit generates a test result according to the plurality of test signals.