Semiconductor Array Test Circuit With Shared Pad Switching
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Solution Overview
Problem
Large arrays of semiconductor devices pose challenges in testing due to the high number of contacts and high production costs associated with late discovery of failed devices, necessitating efficient and cost-effective testing methods.
Innovation Solution
An integrated circuit design with a plurality of devices, each including a driving circuit, individual contact pads, switches, and a shared contact pad, where a controller selectively controls the switches to couple the driving circuits to the shared pad for testing, allowing for reduced current operation in test mode and simultaneous measurement of multiple devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large arrays of semiconductor devices are tested using traditional ATE systems with individual contact pads for each device, then testing coverage and reliability can be ensured, but the number of contacts increases significantly making the system complex and costly
Solution Approach 1:
Multiple individual contact pads are merged into a single shared contact pad through the use of switches. Each driving circuit is connected to the shared contact pad via its own switch, allowing multiple devices to share a common testing contact point. This reduces the number of external contacts from N (where N is the number of devices) to just 1 shared contact pad per device group.
Solution Approach 2:
Switches act as intermediaries between the driving circuits and the shared contact pad. The switches enable selective connection of individual driving circuits to the shared contact pad during testing, allowing the testing system to access multiple devices through a single contact pad while maintaining the ability to test each device individually when needed.
2Reliability
If testing is performed late in production to ensure reliability, then quality control is maintained, but production costs increase due to failed devices not being discovered earlier
Solution Approach 1:
The testing capability is integrated into the semiconductor device array itself during the manufacturing process, allowing defects to be detected early in production rather than late. The on-chip testing circuitry enables preliminary testing of each driving circuit using the shared contact pad structure, identifying failures before they affect final production costs.
3Productivity
If automated test equipment is used to reduce human involvement and test cost, then testing efficiency improves, but the complexity of the testing system increases
Solution Approach 1:
The semiconductor device array performs its own self-testing through the integrated testing circuitry. Each driving circuit can be tested by controlling its associated switch to connect to the shared contact pad, enabling the device to test itself without requiring complex external ATE systems. This self-service capability simplifies the external testing system while maintaining high productivity.
Data Source
AI summary
In accordance with an embodiment, an integrated circuit includes a plurality of devices on the integrated circuit. Each device includes a driving circuit, an individual contact pad coupled to a first terminal of the driving circuit, and a switch having a first terminal coupled to the first terminal of the driving circuit. Also, the integrated circuit includes a shared contact pad coupled to a second terminal of each switch of the plurality of devices. The integrated circuit also includes a controller coupled to each switch of the plurality of devices, where the controller is configured to selectively control each switch to couple each driving circuit to the shared contact pad.